Ferrari 348 Primer For New Owners

(the original enthusiast's guide)

(oh, there are a few things for our Mondial and F355 Brothers, too)

  *348 storm photo thanks to Jas

General Info (spider)



Stated Miles Per Gallon:

Observed MPG:

14/23 mpg

16.3/21 mpg

Curb Weight:

3252 lbs.


Mid-Engine/Rear Drive

Total Quantity Imported Into U.S. (1993-1995):


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1994 Ferrari 348 Spider (Spyder) 

You've got to drive this car! The Ferrari 348 Spider elicits waves, honks, stares, and constant calls from nearby motorists and pedestrians alike. Ordinary drivers morph into paparazzi, turning their digital cameras and video recorders on to film your every move as you drive by with the top down.

What really makes the 348 so special is driving it. You've warmed it up. You've checked your coolant and oil levels. Your gauges report good oil pressure, good water temperature, and good oil temperature. You shift into gear and ease out onto the highway, where a quick blip of the throttle sends you rocketing into the first safe opening on your initial merge. Your blinkers and high-beam flashers are precisely located so that using them becomes an unconscious, effortless act as you change lanes and pass slower traffic.


5-Speed Manual Synch

Just behind you, your ears reward you with the warm low tones of your factory tuned exhaust. If you think about it, you can just hear your transmission conveying your precise rpms back to you. The throaty exhaust isn't overpowering, just pleasant and "there." You can still carry on a casual conversation with your passenger, even with the top down at maximum legal freeway speeds. Wind noise and wind buffeting inside the cockpit aren't even noticeable, save for the occasional light breeze fluttering across your cheeks.

A light flick of your wrists and your 348 has flashed its high beams, signaled left, and changed lanes. A light blip on the throttle and you've passed a slower motorist by. One more light wrist flick and you're back in your driving lane with open road in front of you and smiling drivers behind you.

When you pull into a roadhouse, a crowd gathers to gawk at your car. Many point and whisper "Ferrari."

INDEX *the Index provides a one-click way to jump to major topics of interest, however, there are more topics covered than there are listed in this index. If you don't see what you need in the Index, then click on the Edit button at the top of your web browser and choose the Find option.

Ferrari 348 Primer

Starting a 348 *important for new owners!

348 Pre-Purchase Inspection

348 Post Purchase Prepping **don't miss these tips!

Emergency Roadside Kit

Maintenance Expectations (typical for 348 ownership)

Repair & Maintenance Tips

A/F Mixture

About the 348

Best Place To Sell A 348 (Manheim, et al)

Container Shipping Dimensions (for sending a 348 overseas)

ECU Codes and Check Engine Lights (CEL's)


F355 vs 348 Differences

Ferrari 348 Factory Enhancements (thanks to 348SStb and others)

How To Read Spark Plugs

Modified 348's


Resetting Your Primary (Air/Fuel) ECU's

Technical Service Bulletins (TSB's)



348's In Movies

348 Magazine Articles

348 Manuals/Paperwork

348 Pre-Purchase Inspection

348 Post Purchase Prepping

348 Repair Shops

348 Shifting Tricks

348 VINs

*FEEDBACK: How To Correct Errors On This Page or Add New Information


Ferrari 348 Primer

Although the price of used Ferraris increased across the board after the release of the 430, the Ferrari 348 Spider is still a reasonably priced exotic car. Pristine versions can be had for under $75,000.00 while 348's that have actually been used (gasp, perish the thought) by their owners will typically sell for under $60,000.00.

348's with title problems (duplicate titles, salvage titles, odometer rollbacks, and "corrected" titles) sell for even less. Modern title insurance for your 348 is available through a variety of reputable providers such as, too (so you can minimize your own risk).

Insurance through such firms as Met Life, Hagerty, Leland West, or Grundy can run as little as $800 per year for full coverage, and minor maintenance items such as changing spark plugs (OEM Champion plugs cost a mere $1.67 each) and air filters are child's play for the casual 348 owner. Upgrades to platinum Split-Fire plugs (.028 inch gapping between each point) are desired and trivial in cost. Likewise, performance enhancing K&N air filters can be had for as little as $39 via eBay. Tail lights, parking lights, driving lights, turn indicators, and other lights use common Phillips bulbs that are often for sale for under $2 at name brand retail auto parts stores such as Auto Zone.

The Ferrari 348 Spider has a dry sump for its oil system, so you only check your oil when the motor is hot; never when cold. The oil system and hoses easily hold 11 quarts of your favorite 10W40 synthetic oil (another half quart or more is further held in your oil cooler at any given time), and companies such as Z-Max offer 150,000 mile engine and transmission warranties in exchange for you adding their products religiously every 6 months (regardless of mileage at the time). Your V8 engine design also includes 4 overhead camshafts, a five main bearing crankshaft, nikasil-steel cylinder liners, and centrally mounted spark plugs.

The Ferrari 348 Spider needs to be started and briefly warmed up before casual driving, with extreme track driving not occurring within ten minutes of startup. Rpms should stay well below redline before your oil temperature reaches its operating range(though shifts into 2nd gear should be made *above*, not below, 4100 rpms when cold to avoid clunks). However, Red Line offers a synthetic "Superlight shockproof" gear oil (also rated at 70W90NS) transmission oil that will at least reduce your notchy 1st gear to 2nd gear shifts prior to the transmission warming up, if desired.

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Engine (spider - U.S. version)




3405 cc


312 bhp @ 7700 rpm


237 LB-ft @ 4200 rpm


7800 rpm






It's a three stage process. First, turn the key to run, not start, then fasten your seat belts. Engage the parking brake, clutch, and shift to Neutral. Your 348 has now had time to energize relays and various electrics. Next, turn the ignition key to Start the car. Verify that you have oil pressure (first quarter mark). Let it idle only briefly until your ABS light, BRAKE light, Check engine lights (non-Euro 348's), and Slow Down lights (if any) turn off. At this point, your idle should be down below 1100 RPMs and stable. That's Stage 1. Release the parking brake.

Now begin driving, but initially keep your RPMs well below redline (except, be sure to shift *above* 4100 rpms to go cleanly into 2nd gear when cold). This may be a good point to mention that many, but not all (typically due to wear), models of 348's require the driver to push DOWN on the gear shift in order to shift into Reverse (say, to back out of your driveway after Starting the car per the above steps). Soon you should notice that when you return to idle, that your idle is 1000 RPMs on the money, that you have oil pressure on the first quarter mark on the oil temperature gauge at idle and at mid point by or before 4,000 RPMs. When your oil temperature also reaches the first quarter mark, then Stage 2 has ended (your mainshaft inside your transmission is now warm enough to avoid cold-tranny gear
damage from hard shifts).

With good oil pressure, good oil temperature, and good water temperature, then so long as you have no caution lights on your dash, you are now good for maximum RPMs and full spirited driving.

Welcome to Stage Three. Drive on!


348 Shifting Trick: instead of simply shifting into Reverse, shift into 1st gear and while still holding down the clutch shift into Reverse (do this only when stationary!). This resets the transmission and aids shifting for the rest of your drive (smoother, faster, etc.). Think of this process as a single motion: depress clutch, shift to 1st, continue holding clutch down, shift to Reverse, now release clutch.

Should I lift my foot 100% off of the throttle to complete a normal driving shift into gear? No. 348's need a little throttle to synchronize gear-shifts (some exceptions when the car is stationary).

348's should be parked in first gear, with parking brake engaged. 348 engines should be turned off with the gearshift lever in Neutral (then shift into 1st with engine off), and they should be started with the gearshift lever in Neutral.

About the 348

Your 348 Spider revs quickly from 4,000 RPMs to 7,800. The clutch is light and delightfully precise. Downshifts are a breeze, and contrary to popular myth your downshifts on your 348 do not typically require the burdensome heel-toe-shift maneuver (though that does come into play if you are making extremely wide swings in speed/gears). If you've driven a manual transmission Corvette or Jeep Wrangler, then you'll have some vague idea about the shifting feel of the 348. Downshifting more than 1 gear at a time is not recommended if your downshift destination gear is 1st. Even at slow speeds, downshifting into 2nd gear will prove adequate for city driving, with little or no need to go all the way down to first gear (except at a full stop).

Handling on your 348 is ideal. The car is superbly balanced for its power plant and transmission. While accelerating from any speed, even parking lot velocities, or while motoring at any city speed limit rate, your 348 will carve through slalom courses and scream playfully around a makeshift skidpad with ease. However, 348's do not have power steering. You simply do not want to attempt to turn your wheels when the car is not moving. Other than when stationary or at very low speeds, your 348 has light handling that anyone can enjoy with almost no physical effort. *Note: some 348 drivers claim that adding 25mm spacers to your rear wheels improves your handling. This claim is possible, but as of yet unverified.

Your 348's convertible top is all manual, and does require some strong-arming, especially before you get to know how to work with it. The convertible top's boot cover, however, snaps into place with very little effort and gives your car a clean top-down appearance that is well worth the few seconds required to install.

The 348 has narrow seats. If you have a size 36 inch waist or smaller, you'll absolutely love sitting in the car. Larger waists may have a less favorable impression, so to speak.

The tan, cream, and gray 348 seats avoid the well-known problems of the darker blue and black Ferrari seats (e.g. showing excess wear, getting very hot while out in the Sun with the top down, etc.).

348's come with outstanding factory paint jobs that will last for years with typical care. With all of that said, however, what really makes the car so special is driving it. Have you ever finished a drive and been unable to say anything about your ride except "WOW?!"


Your 348 looks right. It sounds right. It drives right. It's even priced right.

That's not to say that she's perfect, though. A Ferrari 355 has substantially more horsepower. More still for a 360 and more again for the much newer 430. If you've been accustomed to driving anything from a 2005 Corvette to a Porsche Cayenne, then the 348's power and quickness will not awe you.

Your 348's removable rear tube sub-frame or your fuel tank has to come out to change your cam belt (the factory originally recommended changing your belt at 52.5k, checking it every 15k - later most Ferrari dealerships recommended 30,000 mile or 3 year belt changes, however), and most Ferrari dealerships suggest changing out your water pump simultaneously with your belt change. You've even got two drain plugs to deal with for your oil changes (presuming that you like to drain your oil rather than use a wet vacuum to pull it out).

Tires and brake rotors are going to cost you some Dollars, too (though workable replacement parts are available via eBay and other on-line sites).

But while your 348 isn't perfect, it's getting pretty close. Its soft-touch handling, its throaty exhaust sound (not too loud, not too soft), its outstanding good looks, perfectly balanced power, and its smooth ride over potholed streets is rather addictive.

Of course, like all Ferraris, your 348 needs to be driven. Let your 348 sit for more than 3 weeks and your seals become brittle and dry; your shocks become stiff; your tires grow flat spots; water condensates inside your gear box; your battery may even be drained.

Then again, driving this car is easy enough to do. It's NOT driving your 348 that's difficult.

The Story Behind the 348

Ferrari 348 Magazine Articles (U.S.) *Thanks, Miltonian

Ferrari 348 Spider European Magazine Review

The Beauty of Ferrari Chat Forums by No Doubt

Driving My Ferrari 348, by Mathew Pizzi

348 Challenge Race Series - Ferrari Brings Back Gentlemen's Races w/348

Reviving the Ferrari 348 Challenge Races for 2006-2007-2008-2009 (thanks Ira Schwarz and Cavillino Motors)


0-60 mph:

5.3 sec

0-100 mph:

13.15 sec

Quarter Mile:

13.25 sec @ 103 mph



Top Speed:

171 mph

Braking, 60-0 mph:

128 ft

Slalom Speed:

64 mph

  Return To Index


Ferrari 348 Maintenance, Upgrade, Aftermarket Parts, and Repair Tips:

348 Manuals/Paperwork

Owner's Manual From Ferrari *must register, takes a week or so

Owner's Manual for 1994 348 Spider U.S. (name="user" pwd="user") *thanks ben deetman

Ferrari 348 Factory Workshop Manual Volume 1 (90mb)

Ferrari 348 Factory Workshop Manual Volume 2 (90mb)

Ferrari 348 Factory Workshop Manual Volume 3 (90mb) *thanks Ben Bots

Entire Ferrari 348 Factory Workshop Manual (270MB) Click on the "Download With Premium" option button *thanks Henkie

Original Ferrari 348 Manuals, Detailed Factory Service Information, Technical Bulletins, etc.

Ferrari Certification

Ferrari owners can get a certificate of originality from Ferrari for their cars by providing VIN, engine, & some other numbers. Process is on site. Thanks, Verell

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Water Related

Your 348 is cooled by twin coolant radiators (aftermarket radiators) which each have fans that operate simultaneously based on water temp, plus one oil radiator (right side) which has its fan operate independently based upon oil temp, (Low Priced Ferrari Radiator Cooling Fans), positioned on each side of your car behind the doors in the side intake vents.

OVERHEATING: If a 348 or 355 is overheating, you will want to check that your radiator fans are coming on as your temperature increases. Check the radiator fan fuses in the passenger footwell. Swap left and right radiator fan relays there, too.

Common intermittent radiator problem that I never bother to chase until it reoccures after first replacing the fuse... ram effect water from driving in the rain or washing car will cause a heavy draw and blow a radiator fuse. Most common real problem that I have found if they continue to blow a fuse is high resistance at the relay plug in the foot box. Clean the radiator relay male pins with a scotchbrite pad then treat with Stabilant 22a (or replace with a new relay). Thanks, DaveHelms

Feel around the exterior of your radiator cap for coolant (mind that the area could be hot!). Ferrari radiator caps regularly go bad, leaking both coolant and pressure (sometimes to such an extent that your radiator fans won't even come on).

Verify that your radiator grills are not clogged with newspaper/debris.

You can short together the two contacts that connect to the two prongs on your radiator coolant switch to turn on your radiator fan(s) manually. If your radiator fan doesn't turn on via that test, replace the fan. If it does turn them on, then replace the coolant temp switch.

348 Coolant Temp Switch is Ferrari Part #158655 ($18 at DMCann)

348 Coolant Temperature Sensor (different than Coolant Temp Switch)
BOSCH Part # 0280130026 ($18) at

An engine thermostat stuck in the "bypass is open" position will overheat 348's by flowing coolant through the bypass instead of through the radiators. The radiators often won't even heat up enough to turn on the cooling fans in this case, even though the engine is overheating. Changing Your Thermostat

Conversely, an engine thermostat stuck in the "bypass is closed" position will run cold and take an enormous amount of time to reach proper operating temperature (bad for peak horsepower, emissions, and gas mileage).

Bleed your radiators/cooling system with A/C on high heat.

By the way, the left fan (355) is the most important, the right one is a backup. So if the left one is working, you have time to replace the right one, if the left one isn't working then you can switch them while you get the broken one fixed. I have done that, it works...thanks, Cavlino

The right side 355 fan is controled by a unique thermostat. It's oil temp that causes the right side fan to turn on. Left side fan is turned on by coolant temp. Left = water temp., Right = oil temp. thanks, Ferraridriver

348 Overheating Diagnosis and Repair (thanks ernie, Cavillino Motors, ferrarifixer)

If your car overheats at idle, look into your fans and your alternator - your alternator might not be providing the voltage/current the fans need to pump volumes of air through your radiator at idle. Faster Hayden fans might also help.

Use Red Line's Water Wetter (it really works).

RETORQUE your Head Bolts - air leaks here can add air to your coolant system, creating thermal hot pockets. Supposed to be done during 30K service, but its pure labor, so many shops 'skip it' to save time.

When was your thermostat replaced? Water pump bearings/seals? Replace ALL coolant hose sections with new hoses, and use high-torque hose clamps to keep the air out. You can add a 'pulling' fan to your oil radiator. If none of this works, you might want to look into getting your exhaust pipes coated in ceramic inside and out to insulate and remove exhaust heat from the engine compartment faster. *thanks, M.James 

Hose Tip: whenever you have a rubber hose that has welded itself to a metal part, e.g. a radiator hose to radiator or fuel hose to fuel line, you can take something pointy such as a screw driver or scratch awl and try to slide it between the hose and the metal part. Now spray wd 40 between the inside of the hose and the metal part. Then you work the screw driver , scratch awl around the inside of the hose/outside of the metal nipple to unstick the hose. The wd40 really helps loosen things up. Anytime you have rubber touching metal, wd 40 is of great help in getting stuff apart and putting it together. *thanks, osuav8r

I finally found a place to rewind my armature. They did a great job for $55. I thought I would post it here for reference.
Holcombe Armature Co.
905 Rockmart Rd.
Villa Rica, GA 30180
770-459-5544 thanks,
Drew Altemara




How To Pull/Change/Test the right-side 348 Radiators (thanks, ernie, BH1, and No Doubt!)

My new radiator arrived (thanks, Daniel/Ricambi) Friday afternoon and I installed the left-side radiator today. It's a pretty straight forward operation.

Loosen the wheel bolts on the left rear wheel. Now jack up the rear of the car, place a jack stand underneath the rear frame for emergency support (just in case), remove the left rear wheel and inner fender cover (6 phillips screws), remove the radiator cap by hand, drain the left radiator at its bottom right corner (use a large flathead screwdriver) into a 2 gallon catch pan, disconnect the two radiator water hoses and one small gas overflow line (use a flathead screwdriver to loosen the hose clamps on all 3) that is connected by the factory to the fan for convenience (11mm open wrench in back, 10mm socket on left two fan screws).

Now disconnect the fan power wires at the plug and from the fan itself (11mm open wrench in back, 10mm socket on right two fan screws), disconnect the fan, unscrew two screws that hold on the top radiator bracket (13mm socket), then lift slightly up (use a big flathead screwdriver if leverage is required but be careful as the top and bottom of the radiator are made of plastic) to get the radiator's two lower support pins out of the frame of the 348 in order to remove the radiator (be careful to not tear the foam backing behind the radiator that is attached to the 348's body), and replace it with the new radiator.

Reconnect everything. Add coolant until full.

I then had a nice drive (and didn't drip a drop of coolant).

Life is good.

I loosened the two radiator bleed screws on the top right black pipes up on the firewall (10mm open wrench) to attempt to bleed the system with the engine running, then tightened them back up.

I'll have to check when the car has cooled off to see if my coolant level is adequate...though the car ran at very good temps between 185 (after fans had just switched off) to 200 (until fans clicked on again).


Coolant Flush/Fill/Bleeding

I use the Prestone pre-mixed 50/50 green coolant.

The right way to flush the 348 system is to drain the system at each radiator, left and right side, remove your thermostat so that you can plug the coolant bypass hole that is underneath the normal thermostat location, and then pressurize water through your coolant fill cap opening until no more brown radiator rust comes out anywhere...

Now drain the water and refill with Prestone pre-mixed 50/50 green coolant.

And of course, remember to unblock the engine coolant bypass underneath your thermostat as you button it back up.

Now, with your ignition key turned to Run (not Start), set your heater to max high while you bleed your system (you'll just use a wrench to loosen the bleed screws on the right side of your engine bay on the black coolant pipes).


OK, some car owners install coolant filters at this point. You might consider doing the same (less debris hitting your waterpump blades, but slightly reduced coolant flow volume/speed).

Some race-car shops also replace their solid black rubber coolant hoses with transparent FEP Fluoropolymer coolant hoses...this lets you see air bubbles so that you know where your hot spots are located and when it is time to bleed your cooling system...and it helps you spot rust/debris sooner.

Just some thoughts to consider.


Leak Under Left Cockpit Footwell


Radiator Leak just behind and under your right side (passenger side on U.S.) door? Are you certain? Keep in mind that 348's and 355's have an expansion tank coolant vent/drain hose that is *supposed* to drip a little coolant just behind the passenger door after a hot run.

So look underneath your car, find that passenger-side (small) black rubber coolant vent hose, and verify that's not your "leak" before you go to a large amount of radiator removal trouble.

Also check that it isn't your radiator cap that is leaking. An improved 1.1 bar pressure radiator cap is available: Improved 348 Radiator Cap .


Products such as 40 Below and Red Line's Water Wetter will greatly lower your 348's otherwise harsh water temperature swings and extremes into a range more reminiscent of the predictably stable Jeep Grand Cherokee.

Hose Tip: whenever you have a rubber hose that has welded itself to a metal part, e.g. a radiator hose to radiator or fuel hose to fuel line, you can take something pointy such as a screw driver or scratch awl and try to slide it between the hose and the metal part. Now spray wd 40 between the inside of the hose and the metal part. Then you work the screw driver , scratch awl around the inside of the hose/outside of the metal nipple to unstick the hose. The wd40 really helps loosen things up. Anytime you have rubber touching metal, wd 40 is of great help in getting stuff apart and putting it together. *thanks, osuav8r


All that you do to inspect a water pump is rotate it (any squeal/hesitation?), yank on the pulley (any non-rotational movement?), and look at the weep hole on the bottom (is it wet?). Yes to any of the above means rebuild/replace (including the bearings, but the Ferrari waterpump rebuild kit does not include bearings).

People spend more time putting on their pants in the morning (if the engine is already removed from the car and belt removed). It's not some great mystery part. It's a pulley, an impeller, bearings, and seals. Oh, and a housing.


Hi, I am in the UK but send my water pumps to this guy, he is excellent. I had a Lamborghini Diablo pump done by him WITH new bearing, shafts and seals and it was $80 including cleaning the casing! $600 for a bearing, get real Mr Ferrari!
Mr Dick Jordan, 7105 Fountainbleau Road, Ocean Springs, MS. 39564 (228) 872-0855
European Waterpump Specialists - thanks, sulzeruk

ShanB used the water pump and gasket ($495) from Dennis McCann

John DiGiacoma at East Coast Jaguar builds (re-builds) superior 348 and 355 water a fraction (typically a mere $199) of the cost of OEM (often more than $800). These water pumps have twice the Ferrari warranty and they lower parasitic drag by using better bearings. He also uses better seals. Call him at (302) 475-7200 or 1-800-475-9257. An old example of his work is here:


Example of Professional Ferrari Techs Spreading Fear, Uncertainty, and Doubt (FUD) about aftermarket 348 water pumps with which they finally admit to having no direct experience


Common 348/355 Corrosion Points

Electrolysis is a common problem on 348's that don't regularly flush and fill said such a degree that the 3.405 liter V8's twin engine CPU's can receive and send erroneous commands and data because of your old anti-freeze. One way to delay this "electrolysis" is to ground a simple $14 Magnesium anode (zinc anodes don't work for Aluminum, by the way, so DO NOT USE Zinc on your 348) to your aluminum radiator fill tank. *Thanks TR91

( ).


 Wiper Washer(s) squirts on its own

Replace Ferrari part #50332402, the non-return valve (#21) shown here (thanks, Miltonian)

348 Windshield Wiper Washer Pump clone for $17 new


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Your 348 Sounds as though it is "mooing" like a cow when you close the left side door?!'s the fuel tank pressure relief valve. They all do it, and same thing on TR family, even 360.

It's not a problem or a blocked vent or anything, the fuel tank is designed to hold a bit of pressure (generated by engine heat) to help fuel pick up and anti evaporation within the lines on hot start.

It often gets set off when you slam the door as you get out after a hot drive. The shock of the door jars the valve off it's seat.

If thats not must be "an udder" problem that I can't think of......thanks, Ferrarifixer


Ferrari Horn

Researching Ferrari air-horns was sort of a personal interest. I was trying to find the absolute tone of the horn setup, and here's what I found:

The best way to get the authentic sound of Ferrari airhorns is to buy some from a Ferrari salvage yard. FIAMM "Serie 2000" trumpets are made of a light metal and have their own distinct tone which is not duplicated by any aftermarket FIAMM plastic horns or Stebel. Nothing does it better than the real thing.

If salvaged horns cannot be acquired, the absolute closest sound to Ferrari horns you are going to get is with FIAMM, Hella, or Stebel airhorns. The tone is just slightly higher than the Ferrari horns. Only two horn frequencies make that distinct tone: 795Hz and 840Hz. Hella sells these two horns in a package. As for the other two(FIAMM/Stebel), my search came up empty, so I ended up buying the Stebel 3 horn kit and tossed out the longest "3rd" horn (630Hz) during the install for my own car.

-Wolo Horns-
These cheap "made in china" horns are not remotely close to the Ferrari sound. They are simply noise. Thanks, RacerX_GTO


Frozen/Stripped nuts/bolts/fittings?

While doing my CV joints I decided to replace the brake pads and check the trans oil level since I was under the car anyway. I discovered that the little hex head covers on the back of both rear calipers that contain the inboard piston retraction screws are stripped out. I also noticed that the trans fill plug is frozen solid and also partially stripped. I sprayed the plug with PB Blaster and tried a breaker bar. I also tried my electric impact wrench on the plug with no luck. Any ideas on getting these items removed since I'm an amateur at this? Thanks much! - Impacto

First smack both of them head on with a hammer, all the better if it makes the hex hole slightly smaller, then tap in the allen wrench, 3/8 drive ones work best. Then try loosening them.
The last solution is to tap them off using a small chisel on the outer edge, they usually come right out this way. Thanks,

It's very common for the adjuster screw covers to strip out. They're made of plastic. Try:
1) Gripping the edge of the cover with pliars & unscrewing
2) Cut a screwdriver slot into the cover.

Getting a seized fill plug out is more of a challenge. Soak a couple of times/d for 3 or 4 days w/PB Blaster & then try with a 1/2" breaker bar.

If that doesn't get it, try heating the plug with a propane torch a couple of times & let it cool down. The difference in thermal expansion between the iron plug & the Al housing will usually break the corrosion loose when it's temp cycled. Also, the heat will drive the PB Blaster further into the threads.

Let it cool down before trying to break the plug loose. Again, more PB Blaster can't hurt.

Don't use an acetylene or oxy-mapp torch, they get hot enough to melt the Al case. Thanks,


On the brake adjuster covers, I used a sears "bolt-out" tool. Worked perfectly with minimal damage to the cover.
Then I ordered two replacements from Ferrari UK. Thanks, ClydeM


Those are all great tips for removing a stuck bolt. I've got another one, almost as good. Buy your $2.50 pack of JB Weld. Now cold weld your $4 hex wrench into the stuck bolt. Wait overnight. Then turn the formerly stuck bolt. With the bolt out, drimmel it off of your hex wrench if you want to save the wrench, otherwise, toss away both bolt and hex wrench. Thanks, No Doubt


Stripped Threads

I had never used one before --- until I stripped the threads on my oil tank. Tom Jones @ Sport Auto (Summerfield, NC) was incredibly generous and loaned me his kit on a 25-minute advance cry-for-help one Saturday. It was brainlessly simple to use, and extremely strong. Check out the page linked above to see how they work. Thanks,
Jack Russell Racing







Dripping water from your exhaust when your motor is cold? Water vapor is a natural chemical byproduct (one of many) of gasoline/oxygen combustion. Cold exhaust pipes can cause that natural water vapor in your exhaust to condesate into liquid form (i.e. dripping out of your exhaust pipes). This happens most in cold climates when your air/fuel mixture ratio is at its perfect stoichiometric ratio (great for gas mileage, but not ideal for full power so you only want this to occur at idle or very low rpms).

348's have correctly-engineered rear bumpers with cut-outs below our exhaust pipes. This prevents the exhaust water stains that are found on later model Ferraris (the easy solution for those newer cars is to extend your tail pipe tips past your rear bumper).


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Rocking Seats: If your seat rocks forward and backward as you drive, first, for safety, check the four bolts that hold the two seat track rails to your floor. You'll need a metric allen wrench, a flashlight, and some dexterity (that's a joke).

Make certain that you actually have all 4 bolts on driver and passenger seats, and verify that they are tight (and no rust, no broken rails, etc.).

If proper, then move on.

Next, check your seat back positioner. Tilt your upper seat beat all of the way forward, then all of the way back, then set it to your preferred angle and verify that it locks in place. Thanks, No Doubt

If your seat *still* rocks, then you're going to need to remove the side covers on your seats...followed by tightening 3 screws (shown as #28 in the TB/TS drawing or shown as #67 in the Spider illustration) on each side of each seat. See diagrams below. Thanks, Miltonian

TB/TS Above...Spider Below

You may also want to wrap your seat back position pin (that is retained in the latch mechanism) in shrink-wrap to further eliminate the rocking. Thanks, Rexrcr


Removing your 348 seats from the car:

Each seat has two metal tracks that are held down by 4 bolts (shown above as #58 horizontal and #69 vertical). The front two bolts are horizontal. Push the seat all of the way to the back to expose the front two bolts. Now use a metric allen wrench to unbolt them.

Then move the seat all of the way forward to expose the rear two bolts. They are vertical. Now use a metric allen wrench to unbolt them. That's it. Now your seat comes out. Thanks, No Doubt
(OK, some models of 348's have seat-belt brackets that have to be removed, too.)


Headrest Removal

OK, I went out to my garage and pulled my passenger side headrest out of my 348 Spider.

It's easy. First, you must raise your headrest all of the way up and then pry your two black bushes upward until they are both out of the seat.

I just used a flat blade screwdriver. No problem.

Next, you've got to wiggle the headrest just a bit so that the forward-facing notches on the two metal headrest posts are pushed back away from the two headrest-post latches in the seat, and as they are no longer blocked by the latches you can simultaneously lift your headrest up and out of your seat.

The only way that this works is for the bushes to first be raised up and out of the way. When they are up/out of the seat, then your two metal posts will have "wiggle" room. That will let you get around the latches.

Seat Dyes:, They not only manufacture a similar product to leatherique but also still make the lacquer based products mixed to the color You want. they're also suppliers to Mercedes, Jaguar & Bentley amongst others, I've used their products on many cars with good results for both finish and wear. Thanks, Andrewg

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FERRARI Mondial and 348 Light Bulbs/LEDs

1156 Low for Parking and License plate lights (the non "Low" versions will melt the plastic parking light lens on 348's)

1156 regular (also 12821 Phillips) for Front and Rear Turn Signals, Tail lights, Reverse lights, and Brake lights. If you choose the LED ** versions, use the correct matching color (e.g. "red" LEDs ** for tail lights) and 24 LED bulbs with WIDE angle (the versions with only 18 led "bulbs" are too dim and the versions with 30 led bulbs are too wide to fit in 348 sockets). *thanks, jrobbins

74 (or the red LED version **) for the 7 push fit bulbs in our 3rd brake light fixture (348 and 355)

Changing the 3rd Brake Light on F355's and 348's (you'll need a 2.5mm allen wrench and Type 74 bulbs --> see picture ->)

**a note on LEDs: they only work with electricity flowing in the correct direction. This means that you will have to *test* to see if each LED is installed properly (typically there is a resistor that can be seen attached to one wire LED lead, and that should commonly be placed on the top side of any Ferrari circuit plug). On the 348, install your tail light LED, test, and if it doesn't light up simply switch the location of the two power/ground wire plugs that lead into light socket. Test it again. It should then light up. It's plug-and-play easy.

Timing Advantage For LED 3rd Brakes (note when the high-mounted center 3rd brake light LEDs illuminate compared to the two lower brake bulbs)


194 Wedge lights for front and rear (exterior) side lights

125 Dome light for interior overhead light

1445 and 12910 (Phillips) work for the inside of the driver/passenger doors' lights

Most of the above can be found here

9006 for Low Beam headlights (Toshiba/GE 9012 HIR recommended)

9005 for High Beam head lights (GE Nighthawk HB3 or 9011 HIR recommended)

H1 for Fog lights (55W Ultra High Efficacy Plus 50, 55W Narva Rangepower High Efficacy Plus 30, or 55W Tungsram Gold bulbs recommended)

The 26 dash lights/LEDs are wedge fit Type 74 bulbs that push into the OEM twist fit sockets for the rear of the instrument cluster dash pod. *thanks, jrobbins


I'm also under the impression that the Sylvania 2723 is our twist-fit dash light part number. If so, then this LED should replace the entire OEM light & socket I'd guess: .

These lights and/or their LED replacement upgrades can usually be found here and here .


Driver side headlight dancing/bouncing up and down when driving at higher speeds

1) Open up the front trunk lid and look at the back of the headlight bucket (with the headlights down/off). You see the spot welds on the back of the bracket? These have been known to break and cause the headlight to go loose. Check the brackets on both sides of the bucket. If the spot welds have broken, be careful about raising the headlights. If they are crooked, they can get jammed and cause additional damage.

2) Look down at the linkage on the inner side of the bucket, and make sure that everything is attached properly.
3) On your relay panel in the front trunk, relays "H" and "I" operate the left and right headlight lifting motors. If the problem is in the relay (an electrical problem as opposed to a mechanical problem), you can swap these two relays with each other and see if the problem switches to the other side.
*thanks, Miltonian

No Doubt says: Each headlight has a rubber stop in back. That rubber stop is adjustable so that you can stop your headlight from wiggling a little as your car wears. If you are only seeing a mild "wiggle," then that's the place to check. It's the barely visible gleam on the black rubber in the lower-middle center right of Miltonian's picture above.



How to Remove Headlight and/or Motor Assembly


Cleaning Head Light Assembly/Lens


Diagnosing Pop-Up Headlight Systems

Each headlamp lifter has its own fuse and its own relay. If one light lifts properly, but not the other, then swap the two lifter relays to see if the problem switches sides. If the problem switches sides with that swap, then replace the bad relay that you've just identified.

Check both fuses.

If replacing relays/fuses fails to fix your headlamp lifting problem, then you'll need to check the headlamp assembly itself for broken welds, missing bolts, bad diodes, bad motors, and incorrect parts alignment (see below).

pic thanks to Miltonian

Note the diagram and the picture of #6 above. If your headlights pop up then drop back down, or stop at a half-way in between position, then disconnect your battery (these lights pop up on their own with a little pressure...wouldn't want to lose a finger) and verify the position of the lever bar/lifting motor and the #6 bar that connects the lifter to the headlamp. Adjust as necessary. Reconnect your battery and test.

If the above doesn't fix your problem, then disconnect your battery and test the position "sensor" diodes. These diodes can be tested in situ with a simple digital voltmeter set for resistance.

Apply the DMM leads to the Black and Grey terminals. You should get a high resistance reading with the leads one way, then switch the leads from black to grey and grey to black and you should get a low resistance reading the other way.

Two high readings or two low readings (i.e. leads used in both positions) would be a bad diode. In contrast, a good diode will have one low resistance reading and one high resistance reading. Diodes block current flow in one direction but permit it in the other, after all, so measuring with the leads one way will see low resistance...while the other way (for a working diode) will see near infinite resistance or even a complete "open" circuit.

Repeat for Black to Black/Green terminals. Common diode 1N4001 is an acceptable replacement ($0.06 at

Samy reports: The diodes are somewhere else, not inside the motor. They only prevent the 12v coming in on one wire via the switch relay from going out to the other contact of the switch relay, and only go out on the third wire which goes to another relay which put 12v onto the motor.

The switch relay is controlled by the column lightswitch. If the switch is off then the switch relay puts 12v onto one of the two lifter motor wires, and with the diodes inside the motor is a plate with some holes in it. If the contact with the 12v is on the metal surface of the plate then the 12v go out to the second relay and the lifter motor starts until the contact is over a hole in the plate (the contact moves with the motor). Thats why the headlight normally goes to the closed position by itself when the power cables are first connected.

When you turn on the light the switch relay puts 12v onto the other cable with the diode and there another contact is on the metal part of the plate and the motor runs until this contact is over a hole on the plate. One of my three contacts was damaged so my headlight only opened and never closed. Also the metal plate was damaged from rust, so I welded the plate and soldered something onto the broken contact so now it has contact and my lights lift up and go down on command.


Reverse Light Problem

Steering/Light Stalk Switch Repaired 

Turn Signals (blinkers) Not Working, But Hazard Lights Are Working

It should be Fuse nr.7 in the passenger foot rest , counted from right to left of the upper line of fuses. 10 Ampere. If it's this fuse your reverse driving light shouldn't work also. Hazard lights have an different fuse its Nr 16. Thats why these are still working. Thanks, Samy

Turn Signals and Emergency Hazards Both Failed

It was the electronic flasher unit. I replaced it with an EP36 by stant/tridon ($8 at AutoZone)
from an auto store. Same basic specs just a different package, doesn't have the tab to mount it to
the bulkhead. Thanks,



 Erratic headlight/dash light behavior (e.g. dash lights remaining on after ignition key removed):

You've got current flowing in the wrong direction in your dash. This can happen for a variety of reasons, not limited to:
crossed wiring, burned out dash bulbs, bad ground connections, bad battery ground, bad battery, bad alternator/diode, bad relay(s), bad turn signal/bright light stalk, bad ignition switch, etc.

If the car has *ever* been jump started, then yank your battery out and replace it with a new one. That may, repeat, may save your alternator and might even cure your electrical gremlins.

If your dash lights are stuck on (when you've already removed your key from your ignition), then open up your foot panel to expose your fuse/relay panel in the cockpit., remove your relays one by one until your lights go out (re-install that relay and check to see if any other relay also solves your problem, ad nausium). This should narrow down which circuit is problematic.

Next, remove the 2 phillips screws that hold your black driver dash pod to the dash. Turn the pod gently around, unplug each wiring clip, and apply Stabilant 22a liberally to the metallic connections. Repeat this process for each bulb in your dash pod, too. If you have any dash lights that are burned out or very, very dim, then replace them (preferably with LEDs because LEDs don't allow current to flow in reverse). Plug it all back up, put it back on your dash, tighten down your 2 phillips screws, and see if that solved your problem (verify that all dash bulbs/LEDs work).

Finally, apply liberal amounts of Stabilant 22a to the rotary ground disconnect switch that sits above your battery (as well as to your battery contacts themselves).

Disconnect your battery for 30 seconds. Now start up your 348 and DO NOT TOUCH THE THROTTLE until after your engine has heated up enough to turn on your radiator fans. This will give your A/F ECU's time to relearn your car...a process that generally solves many, many 348 problems (and is free to try).

By the way, your passing flashers only work when all of your lights are off. Likewise, make certain that your green "parking light" button on the center vertical console is not pressed in/activated.

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Many Ferrari 348 internal parts are industry-standard generic parts. If you buy them from a Ferrari Dealership, they will be packaged in a yellow Ferrari box and will come with a Ferrari Warranty. If you buy them from GM, ACDelco, or some other parts supplier, they will come in a wide variety of boxes. Typically the actual auto part inside any of the boxes will be identical to that sold/packaged in any other box, though the prices will vary by as much as ten times.

The Ultimate 348 OEM To Aftermarket Parts Cross-Reference

This web site recommends first trying the big 3 generic auto parts distributors (,, and If you can't find your part at one of those locations, try one of the speciality Ferrari independents (listed below). Also, keep in mind that prices vary even among different Ferrari dealerships (differing markups).

In the end, you're quite likely to wind up with the same part regardless of where you buy it or how it is packaged.

AMP Connectors For O2/Coils/Power Trans/Crank Sens/Idle-Reg/Phase Sensor Wiring (thanks, DaveHanda)

Used Ferrari Emblems/Parts

Carbon Fiber Cloth and Tape and Resin Supplies

Molds and Cloth Fiber Supplies For Fabbing Your Own Parts

Ferrari 348 Relays ~$5 each (thanks 91tr)

Low Priced Ferrari Radiator Cooling Fans

Aftermarket Radiators

Oil Cooler Thermo-Switch: Intermotor part number 50172 replaces the OEM part 123277 without any modification. OEM part costs approx £65 - aftermarket part approx £10.
Intermotor 50172 (as seen on the Volvo 300 series circa 1988)
closes - 87 degrees C, opens - 82 degrees C, M14 x 1.5 Thread

Hill Engineering part number TS-348 for about $70.
OEM 123277
The thermoswitch for the oil cooler fan should close at 90 degrees C, turning on the fan, and open again at 80 degrees C, turning off the fan.


Ferrari 348 Fuel Filters For Only $8.55!

(search for 0 450 905 601 or 71039)Also, remember to buy your new "small" ring seals (44-43-483) and buy new "large" seal rings (41-61-162) in addition to fuel-safe teflon plumbers' tape for the threaded connection ends on the pipes.

Ferrari 348 aftermarket fuel pump (python) for $156

Fuel pressure regulators are Ferrari part number 147281 (Bosch #0 280 160 731 available for $138 at, about $180 each at Ricambi or an outrageous $600+ at Ferrari dealerships. But...I'm reasonably sure that they are just AC Delco FP regulators. The AC Delco part number is 217-2119 and the GM part number is 35476530. You can get them for $81 each here if you don't mind forgoing the pretty yellow Ferrari shipping box: . The STANDARD MOTOR PRODUCTS FP Regulator # PR171 (~~$75 at should work on our 348's, as well. The AirTex Fuel Pressure Regulator (Part # 5G1020) for our 348's is only $59 at, too. These fuel pressure regulators should all be exactly the same, and interchangeable at will.

However, 1993 and later 348's (all 348 Spiders) use Bosch Fuel Pressure Regulator 0 280 160 738, instead. The difference between the 2 FPR's is the 731 regulator uses a rubber hose clamped with a hose clamp. The 738 version uses hard compression type fittings.  This is an inexpensive Bosch part, found here at RockAuto for $75.  The 0280160738 part looks like this:
0280160738 FPR for 348 Spiders


The 355 FUEL INJECTORs for the F355 2.7 MOTRONIC (BOSCH # 0280155003) are part #149316. They retail for $650+ each at Ferrari, Eurospares, etc., are just $99 at! and search for parts on the Bosch #0280155003

The 348's fuel injectors are Ferrari part #142434 (Bosch # 0280150731): $113 at RockAuto ($96 each if you want the generic STANDARD MOTOR PRODUCTS Part # FJ162), and rebuilt injectors (GB REMANUFACTURING Part # 85420117) for $30 each if you send in your old injector cores to RockAuto (or $41 each without shipping your injector cores to them). Yup. Parts that sell for more than $650 can be had new or rebuilt for as little as $30 each.


BOSCH Part # 69535
{348 Fuel Pump - Elec} ($224) at

Python Fuel Pump (Clone) $156

Fuel Pumps, MAFs, and ECUs sold new, repaired, and used

A considerably cheaper alternative to the OEM O2 sensor: O'Reilley Auto Parts carries the superior Borg Warner 4-wire factory-fit-harness O2 sensor for the 348 ($65). This BWD/BG part number is OS582.

Bosch makes a universal sensor, Part # 15727, that works perfectly on the 348. . The dealer can charge $350 a piece for OE replacements but you can get the universals for about $65 a piece. The other nice thing about them is that they are a stock item at Napa, Autozone, Rock Auto, or Advance Auto Parts. All you need to do is keep the black plastic electrical connectors from the old O2 sensors (you'll hand splice the old connectors onto the universal O2 sensor).

I've also successfully used the Walker 4 wire generic O2 sensor in my 348. You have to splice it in to the factory O2's wiring harness, but it's only $25 on eBay. Ditto for the Borg Warner 4 wire universal. has our crank sensors (Ferrari 348 part #130975) for $119 (volvo part# 1367645).

This site lists that Volvo part (1367645-7) and the Bosch part (0 261 210 029 ) as the same thing:

Our 348 crank sensors are also Fiat part # 7616269 and Kia # 0K2A6-18-891

The SECONDARY AIR VALVE / One-Way Check Valve Part No. 148494 for 348's, Mondial's, 355's, 550 Maranello, Testarossa, 512M, and F50 (typically $125+) is interchangeable with the older 308/328 part #121769 ($15 at

The $250 Ferrari 348 IDLE ADJUSTMENT REGULATOR Part No. 142432 is Bosch part #0280140505, which just happens to be VW/Audi part #034133455 (available used for as little as $59 here: , or dented for $95 here: ). But even if you have to pay $200+ for it new, it's still somewhat useful for those of us without authorized Ferrari dealerships in town to be able to walk into the local VW/Audi/Saab dealership to pick up a Ferrari 348 part.

Clone 348 Idle Adjustment Regulator for $113 new

Real 348 Idle Air Regulator $166 new:
Not only will Kingsborne custom make your Ferrari 348 spark plug wires (about $625 per set with lifetime warranty), but they'll wrap them in 1200 degree color coordinated external sleeves: . Also, will custom make your 348 wires for less than $170 per side. In addition, T Rutlands typically carries aftermarket wires for 348's in stock for around $650.

An improved cap is available: Improved 348 Radiator Cap .

$80 water pump rebuilds: Mr Dick Jordan, 7105 Fountainbleau Road, Ocean Springs, MS. 39564 (228)872-0855 European Waterpump Specialists - thanks, sulzeruk


John DiGiacoma at East Coast Jaguar builds (re-builds) superior 348 and 355 water a fraction (typically a mere $199) of the cost of OEM (often more than $800). These water pumps have twice the Ferrari warranty and they lower parasitic drag by using better bearings. He also uses better seals. Call him at (302) 475-7200 or 1-800-475-9257. An old example of his work is here:

Aftermarket Ferrari Starter Motors

I finally found a place to rewind my armature. They did a great job for $55. I thought I would post it here for reference.
Holcombe Armature Co.
905 Rockmart Rd.
Villa Rica, GA 30180
770-459-5544 thanks, Drew Altemara

This site claims to have $322 aftermarket replacement (direct fit) catalytic converters for 1992 348's

This site claims a 1990 Mondial T cat for $352 that could potentially fit 348's


Ferrari 348 aftermarket brake discs/rotors:
Brembo 25261 (front): $240
Brembo 25263 (rear) : $220

Powerslot Cryo-treated 477CSL, 477CSR (front r,l): $215
Powerslot Cryo-treated 478CSL, 478CSR (rear r,l): $311

For non-track, pure street use, the Axxis "Metal Master" brake pads are the BEST for reducing brake noise, giving good stopping power and minimizing brake dust on 348's. And they're only $56 a pair.


EMachineShop will make parts to your measurements, too also has free downloadable software, and is focused just on flat plates, therefore costs are a lot lower comparatively (thanks, snj5)

 348 Car Keys: Just about every hardware store in the U.S. carries the Silca and Ilco "X152 FT46" key blank. Cost? About $2. These blanks can be cut by the hardware store and will operate your 348 door locks and ignition. The Ilco fits Fiats and Ferraris alike. The better looking rubber headed versions cost about $8 here.

$7 Ferrari Key Chains

GT CAR PARTS 623-780-2200

"The heater stopped heating on my 1984 Mondial QV due to fault in the Bosch electrovalve (relay) in right footwell under dash. The same Bosch part for 1984 BMW 528 was $28.00 versus $170 from Ferrari dealer." Thanks, ktmrider in Modena Italy. Contact Cigarini Flavio in parts at 059 281357 or fax 059 281357
email This guy is really helpful, speaks english ok and is happy to ship stateside! You can get your parts if you have the partnumber, usually cheaper and faster than through Ferrari dealerships. Thanks, Erik R. Jonsson


Custom Ferrari Emblems
This site is now handling 348 parts because the 348 is more than 10 years out of production (1995 was the last official 348 year model), however, their web page has not yet been updated to this effect so you may have to email them or call them to inquire about a specific part:


Good morning, we are handling 348's if you can let me know what items you
require I can deal with your enquiry
Darren Alderman a.m.i.m.i
Maranello Ferrari Parts Dept
main line: 01784-436222
direct line: 01784-486634
fax line : 01784-436303
01303 814819 or 07845648259 also has a few wrecked 348s from which they will sell individual parts.

You could also have lexan covers from the 348 Competizione cut to fit for your 348 here:

Ferrari Parts Cross Reference To Industry Generic Equivilents *still a WIP

Koenig Enhancements

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Pre-1993 348 Outer Rear Wheel Bearings (SKF): new from Applied = $105 each (877-279-2799), or $113 from Ferrari of Dallas for bearing part #144807 (SKF # 62209-2RS1 or SKF 62209-2RS2), or $40 each from Gerardi Bearing Co.(Salinas, CA).

Outer rear wheel bearing hub assembly for 1993-1995 348's (and early 355's) was Ferrari part #143172 and is now #157900 (new $677 at Ferrari of Atlanta, $594 at Ferrari of Dallas, $456 at, or $368 from EuroSpares).

Early 348 front bearing removal

Early 348 rear wheel bearing replacement


Late Ferrari 348 and 355 rear hub bearing assembly pictorial replacement

Late Ferrari 348/355 Sealed Wheel Hub Bearing Grease Repacking Pictorial

Last couple of times I took the 348 out I noticed a slight noise coming from the left rear.

Stayed the same in acceleration and deceleration so could probably rule out gearbox (thank goodness), seemed to go away when turning right so sounded like a wheel bearing. I had looked at the bearings before and they looked like a "sealed for life" unit, but thought that since they were probably RS did not really matter if I stuffed them up pulling them apart.

So I put one in the press and popped it apart, came apart very easily and I then found the reason for the noise. The grease had obviously been there since leaving the factory in 93 and was dry, rock hard and pushed well back from the balls. I finished taking them apart and cleaned them up expecting to see damage to the balls, races and seals but they all cleaned up perfectly, no scores, blueing or anything.

So just repacked the bearings with high temp bearing grease put them back together and bingo problem solved.

I had taken the stake nut from the drive shaft to a CV repair shop and they matched it up (apparently a very common size as they had boxes of them). Cost $5 each.

So total cost $10 plus a bit of grease and about 2 hours, bit better than the $1300au I was bracing myself for 2 new hub/wheel bearings.

The procedure I used was:

1. Jack up car and put on axle stands and remove wheels.

2. Remove brake caliper and disk.

3. Remove park brake shoes for rear hubs, (you can work around them but it easier with them out of the way.)

4. Unstake axle nut.

5. Remove nut, (my rattle gun did not have the cajones for this so had to use a breaker bar).

6. Push the axle as far in as you can and then you can get in behind to undo the 4 hub mounting bolts.

When the stake nut is done up it pulls the flange of the CV Joint over the 4 hub mounting bolts and you cannot get a socket on them. At first I thought I had to undo the wish bones and remove the upright in order to get access to the bolts. I later worked out that by just taking off the stake nut and pushing the splined axle in with your thumb it got enough space behind to get a socket onto the bolts (that’s the really bad third picture)

7. Remove hub put in shop press and press centre out from the back.

Sorry don’t have a pic in the press but attached is a pic of the rear of the bearing notice the inner section of the assembly with the splined shaft this if the section to be pushed out. (My press is a crappy $50.00 Chinese one but did the job fine)

8. Use a brass/aluminium drift on the balls to pop the seals out.

Once you have the centre of the bearing out you will notice that one seal is internal and one is external, I find the safest way not to damage the seals is just to turn them over on a piece of clumped up rag and gently tap the bearing with a soft drift. This then pushes out the seal without damage.

9. Clean thoroughly and repack with your favourite grease.

I pulled the balls out of the plastic race and washed them all in kerosene along with the seals and the other parts some bits took a bit of scrubbing with an old tooth brush. I had some Valvoline bearing grease on the shelf so used that I am sure are much better products out there. I have been using this stuff on car and boat trailers & the loads on the back of the Ferrari are probably not as great as that.

10. When re-pressing back together DO NOT push fully home, leave say 1mm or so to go otherwise you will put too much preload on the bearing. If you leave a bit of a gap when you do up the stake nut this will pull it down and give the right preload.

The attached picture with red arrow probably shows this, notice how the inner splined section is about maybe 1 mm lower than the outer face of the bearing.

If you look at the pic below of the axle you will note that there is a small step (with silver "never seize" on it). As the stake nut is done up it will pull the inner section of the bearing down to the height of step and bingo correct pre load. If you don’t leave the gap you will soon know it the bearing will be locked up.

11. Reassemble with a new stake nut and you are good to go.
Just reverse the process to reassemble.
Hope this all make sense.

Thanks! gidge348


Pre-1994 outer Front Wheel Bearings for 348's (and for most Ferrari's made from the 1970's up through to the 348) may be able to be purchased for less than $15 here: (post 1993 cars could retrofit to these bearing by purchasing some additional older axle components).

Save 80% Or More On Bearings

The 348 uses a Porsche 911 turbo (930) CV boot. The 348's CV joint is 108 mm diameter x 40mm wide and the Porsche part # 90133229312 boot should fit it and cost about $6 per boot (no grease or clamps). Ferrari uses industry standard, third party LOBRO CV joints, supplier to VW, Audi, and Porsche among others ( ). Just take your boot to a reputable import car parts store that serves the trade, one preferably specializing in the fore-mentioned brands, and get the most senior person to match it up. They will have catalogs with the dimensions of all the boots available.

Bearing noise from the rear of your 348?? Are you sure? Parking brakes in need of adjustment sound strikingly similar to failed CV joints, bearings, and bearing assemblies (as you drive close to a parallel wall, do you hear a regular metallic rattle or drum cymbal sound?). To test: slowly apply your parking brake as you are driving. If the noise disappears, then your parking brake probably needs adjustment (much cheaper to adjust that brake than to replace the wheel hub bearing or the whole half-shaft axle CV joint assembly!). - Thanks, No Doubt.

Another bearing noise test is to simply use a grease gun to pump good, synthetic axle grease into the CV joint area beneath your outermost rubber CV boot covers (e.g. when one such rubber boot already has a split or hole in it). This too could potentially solve your bearing noise problem without having to replace an entire axle. - Thanks, FatBillyBob.

 Return To Index


Slow Down Lights

Common Causes of 348/355 "Slow Down" Warning Lights and/or Reduced Performance:

Your 348 or 355 may encounter a "half power" condition in which an entire bank of cylinders appears to be shut down. This shutdown signal originates with a thermo sensor on a cat, goes through an exhaust ECU that is located under each shock tower under the rear engine hood/bonnet, and procedes to your dash warning lights and Air/Fuel ECU's that are located behind each seat in the cockpit itself. After 5 minutes or so of showing the SLOW DOWN 1-4 and/or SLOW DOWN 5-8 warning light, your A/F ECU's will shut off on or both banks of cylinders. Your SLOW DOWN 1-4 light is located on the *right* side of your instrument cluster; your SLOW DOWN 5-8 warning light is on the *left* side.

This is because your engine's 1-4 cylinders are on the right side of your 348, and your 5-8 cylinders are on your left side.

Ernie suggests that you get some Permatex black silicone. It costs about $3 for a tube of it. Then after you have taken the car out for a nice Italian tune-up-drive (the heat will help evaporate moisture that's already penetrated these old units), jack up the rear, remove both rear wheels and inner fender liners, unbolt/unplug and pull out both of the exhaust ecu's and seal them up good with the silicone (seal everything except the electrical wires, of course). That should keep the moisture from getting inside the cat ecu (the main killer of these $400+ parts), and then it shouldn't be able to build up the condensation from sitting all night.


I bought a new $20 laser thermometer (for sale at Radio Shack and other such places). You point the laser at whatever you want to measure (e.g. catalytic converter, air conditioner vents, etc.) and it tells you the temp (up to about 420 degrees F, anyway). Well, after a normal city traffic drive plus a little idling, my 348's cats typically register 370 degrees F to 395 degrees F, give or take. Above 420 degrees my el cheapo meter just blanks out...which would be up toward the temps that might indicate a cat overheating issue (especially above 650 F).

Anyway, if you measure the temp of your cats and you get a low temp such as the above, then it probably isn't a cat overheating problem.

On the other hand, a high cat temp (glowing a dim red would be bad!) is cause for concern. It could be coming from unburned fuel (e.g. bad spark plug) entering a cat. Could be from a clogged cat.

So what ECU codes are in memory? No need to guess blindly. Swapping the exhaust ecus is a fine idea to see if your SLOW DOWN lights switch sides, but the error codes will let you be even more clever about your debugging in the first place. So the first thing to do is to pull your Check Engine codes. One of the potential codes is for cat temp being too high (would be good to know!). Another code is for a faulty/unplugged exhaust ecu. Good to know if either of those codes are in memory, among others.

You should have a red button tethered to a cable to each ECU (if not, they are cheap to buy from Ricambi America), see pic below for ECU.

Your two air/fuel ECUs are behind your seats. The 5/8 is behind the U.S. left-side driver's seat. The 1/4 ecu is behind the right side seat. You'll want to pull the codes on the same side as your SLOW DOWN light (so for the SLOW DOWN 1/4 light, you'll pull the 1/4 ecu codes).

There is a large panel behind the seats that covers the ECUs in the Spider, or two smaller panels for the 348 TS/TBs. You just put a flat-blade screw-driver onto each of the black plastic "screws" and turn 90 degrees to remove the panel(s). Then you can see the ECUs (and hopefully their cables/buttons).


NOTE: If you pull only a 4444 or 4114 code (with the engine off), then your SLOW DOWN light may be coming on due to your engine computer being turned off (cycled) by its ECU relay under your passenger footwell. When the power is turned back on, your engine ECU and exhaust ECU will perform their self-diagnostic tests, which will flash the appropriate CEL and SLOW DOWN lights (even while you are driving!). If that's the case, then no code other than the "all clear" 4444 code be saved in your engine ECU for that side of your 348, because the error codes are not kept in memory when the power to an ECU is turned off.

Swapping engine ECU relays is a typical test in that circumstance to see if the problem switches sides.

Oh, and for whatever it's worth, I highly recommend paying West Marine or an on-line store ( the $130 for one of these automatic fire extinguishers for your engine bay. It's cheap peace of mind for our high-performance, gasoline-burning machines.

Do any of your spark plugs appear fouled? Notice any misses? Backfires?

One such cause may be a bad spark plug wire (which is typically encountered at low RPMs but not at high RPMs). A bad plug wire means a bad spark burn, which means that excess fuel goes unburned and into your cats, which can overheat your cats, which leads to a Slow Down light or two prior to a failed cat (or two) or a car fire. Slow Down lights are important safety warnings.

1. Modern Ferrari spark plug wires generally do not suffer failures that will be found with an ohm meter. The problem they suffer is a breakdown in the insulation allowing them to "Leak" or short to ground or another wire. The loss is not always even complete.

It is compounded by the fact that unlike American cars where the standard has always been to elevate, insulate and separate the wires to prevent just that, the Europeans (as very well shown on the 355) tightly bundle them and cram them in a hot grounded metal area that requires an absolutely perfect wire to perform properly.

Standard repair method on 348, 355, 456, 550 for rough idle [or power loss] not immediately attributable to any other cause:
A Throw away the Champion plugs and install NGK's.
B Install new spark plug wires.
God bless coil on plug ignition. - thanks, rifledriver
Not only will Kingsborne custom make your Ferrari 348 spark plug wires (about $625 per set with lifetime warranty), but they'll wrap them in 1200 degree color coordinated external sleeves: . Also, will custom make your 348 wires for less than $170 per side. In addition, T Rutlands typically carries aftermarket wires for 348's in stock for around $650.

Another cause may be your cats, MAFs, O2 sensors, exhaust ECU's, or a bad Ground connection.

2. Catalytic Converters. 348's and 355's have dual "cats" that each have a temperature sensor and an exhaust ECU. If your 348/355 runs too rich, or if one or more of your cats becomes covered with debris or insulation or rust, or if your cats become clogged over time, then your exhaust ECU's will trigger a Slow Down warning. You have two "slow down" lights on your dashboard, one for each bank of cylinders (1-4 and 5-8) that feed each cat. These old technology, baffled cats will glow a dim red when too hot, and can cause catastrophic engine fires if allowed to continue to heat up. If you drive slower, i.e. "slow down," their temperature will often (not always) decrease.

 (left side exhaust ECU location pointed to by Miltonian's famous cue stick)


 (exhaust ECU)

The exhaust ECU's can also generate false warning signals (either from bad ECU's or from bad connections or from a bad thermo sensor). This typically happens when water has penetrated your exhaust ECU framing box(es). It could also happen if the thermocouple on the cat has its two wires shorted together, and could likewise trigger a false signal if either or both of those thermocouple wires are broken (open circuit will trigger a CEL).

In either case (real overheating or false signal), the 348 and 355 ECU's will first light up your appropriate Slow Down light (1-4 or 5-8), and if the warning from the exhaust ECU(s) continues (usually about 5 minutes), will shut off the entire offending bank of cylinders. At best, your car will then run on only four cylinders, at substantially less than half power (a "limp home" mode).

The typical repair process starts by examining the cats after a Slow Down light has been lit. If either or both cats is/are glowing a dim red or otherwise emitting a large amount of heat, then your Ferrari should NOT be driven any further and other diagnosis procedures below should be avoided or handled by professionals. At that point you will to identify which components need replacing such as O2 sensors and cats (preferably with more modern Hyper-Flow converters) before proceeding. Both O2 sensors and catalytic converters eventually fail. You may need to replace your spark plugs and/or spark plug wires and ignition coils, too (because fuel that is unburned in your cylinders will heat up your cats). You may need to clean your air filter and lean out your A/F mixture, as well. At the very least verify that the resistance measured between male pins #1 and #6 on your MAFs are identical and close to the factory pre-set 383 ohms (see section on A/F mixture adjustments/tuning). Your timing may also need adjustment, ditto for fuel pressure regulation and fuel check valves.

If your cats are NOT emitting a large amount of unusual heat, then simply switch exhaust ECU's from one side of your car to the other. This will let you test for a bad exhaust ECU. If your Slow Down warning light then changes from Slow Down 1-4 to Slow Down 5-8 (or vice versa), you have identified a bad exhaust ECU. Replace it or send it out to be repaired (e.g. to BBA-Reman).

If the Slow Down light does not switch sides after you've moved your exhaust ECU's to opposite sides of your car, then attach a clean, new, additional Ground wire to your O2 sensor (and then likewise to a Ground point on your frame) on the offending side. You may also have to replace your exhaust temperature sensors. Also, insure that your exhaust thermocouple is in proper condition. *thanks, No Doubt

To help identify which components have failed, you generally follow the same tactic of switching sides. Our 348's are set up in a mirrored fashion such that we can move components from the left side of the engine to the right side, and from the right side to the, when a problem switches sides after a component swap, then it usually means that was the offending component.

I'd suggest switching coils from left side to right side to see if the problem switches sides with a bad coil, if not, then I'd try swapping the left bank of 4 spark plug wires with the right bank of 4 wires to see if the problem switches sides...which would identify a bad spark plug wire.

Measure the resistance under the MAF cable on the male MAF #1 and #6 pins (extreme ends of the cable connection, but on the MAF itself) with the engine off. You should see identical resistance values on left and right sides (for reference, the factory pre-set value is 383 ohms).

You can then swap MAFs from left side to right to see if the problem switches sides in order to identify a bad MAF.

If none of the above helps, then the cheap thing to do would be to swap cats from left to right side to identify a failed/clogged cat (if the slow down light swaps sides then, of course).


O2 Sensors

If your 348 experiences slight surges / surging (up or down) in power while you are driving at a constant speed on level ground (but runs fine at full throttle), then you probably have one or more dying O2 sensors. Replace one or both and your surges should go away.

Failing 348 O2 sensors are the #1 cause of all Check Engine Lights (CEL's), especially code 1211, and are one of the top causes of poor idles when your car is hot (O2's are ignored when your engine is cold).


A considerably cheaper alternative to the OEM O2 sensor: O'Reilley Auto Parts carries the superior Borg Warner 4-wire factory-fit-harness O2 sensor for the 348 ($65). This BWD/BG part number is OS582. These are 4 wire O2 Sensors that DO NOT need to be spliced to your original O2 black plastic electrical connectors. They are sold with a wiring harness that is plug and play.

Bosch makes a universal sensor, Part # 15727, that works perfectly on the 1994 model year 348. . The dealer can charge $350 a piece for OE replacements but you can get the universals for about $65 a piece. The Walker 4 wire generic O2 sensor must likewise be spliced in, but it's only $25 on eBay. The other nice thing about them is that they are a stock item at Napa, Autozone, Rock Auto, or Advance Auto Parts. All you need to do is keep the black plastic electrical connectors from the old O2 sensors (you'll hand splice the old connectors onto the universal O2 sensor).

Also the plug-and-play BOSCH OEM O2 sensor itself (Bosch part # 13120 or 13240) can be had at Auto Zone for a mere $160 (and the aftermarket 348 Walker plug and play O2 sensor that requires no wire splicing is only $110)...So forget about going to the Ferrari dealer and paying through the nose for the same OEM BOSCH O2 sensor...Get one through your local Auto Zone store for less...

The original Bosch part number for the O2 sensors is, 0 258 003 103.

But when I looked up the sensor it was superseded by part number 0 258 003 222.

I also found out that a Volvo 850 uses the same O2 sensors. I got the plug and play version. I didn't feel like fooling around with splicing wires. That and the price wasn't bad, $125 each.

Keep in mind that you can see, reach, and quickly change your 348's O2 sensors with a simple hand wrench or (cut out) socket (correct tool to use is a 22mm O2 Sensor socket tool that usually costs $14 - thanks, T A - Tech), though you might want to prep your job by applying a quality penetrating oil such as "Liquid Wrench" (cold engine only) a few hours before you start unscrewing your old O2 sensors.

ALSO: Do Not Permit Silicon Spray or even WD40 near your O2 sensors: they can kill the O2 detector.

Remember to use O2-Sensor-safe anti-seize compound on the O2 Sensor threads, too...standard anti-seize compounds will emit fumes that can degrade O2 sensing ability.


How To Change 348 O2 Sensors

I just changed out one of my O2 sensors last week. I did it from the top, looking down:Wide Angle View of O2 Sensor Location
Zoomed View of O2 Sensor Location

 Unbolt the 4 nuts that hold down your air filter, then unscrew the 2 hose clamps that connect the black u-turn air tubes to each of your MAFs and pull them up/away from the MAFs a small distance. Now just unscrew the two small hose clamps that hold the two tiny air hoses at the bottom of your air filter.

This will let you rotate your entire air filter box (which itself remains closed) toward the back of the car while still connected everywhere else. You don't really have to move the air filter box out of the way, but it's a heck of a lot easier to see the two plastic O2 electrical connectors (per O2 sensor) that are under there (especially the very first time that you do this job), and you've got to get your hands on those.

With the air box removed, you will have access to the O2 sensor connections:

Black O2 Electrical Connectors

To remove the connectors all you have to do is press down on the clip that is on the top of the connector, then pull it out:Press Bar To Disconnect

 At this point, you push down on each tiny little metal bar to allow you to disconnect each of the two black plastic O2 electrical connectors under there (per O2 sensor being changed). Each connector has two wires, and then those 4 wires go into an insulator all the way down to the O2 sensor itself.

With those disconnected you can now put a special 22mm cut-out O2 removal socket onto your O2 sensor. I had purchased a 7/8th inch one years ago for a Jeep, and it fit my 348 Spider O2 sensor perfectly. Cost me $14 at NAPA way back when, and that let me use a ratchet/socket looking down from the open hood bonnet.

An open end wrench would do as well, though the leverage from the top would be difficult (simply remove a rear wheel and unscrew the black plastic "inner fender guards" if you want to use an open-ended wrench - that would let you go in from the side rather than from the top):View Through Wheelwell To Use 22mm Open End Wrench

You can always take your new O2 sensor to your local auto-parts store and try various $14 O2 sockets to insure that you get the right size tool, but it's 22mm.

I had squirted one blast of "Liquid Wrench" on the base of the old O2 in my cat the night before. A single one-handed yank on my small ratchet/O2-tool then dislodged my old O2 sensor the next day.

Unscrewed the old sensor, screwed in the new sensor, then plugged the O2 sensor in, then reconnected my air filter hoses...

...only to discover that my new O2 sensor was giving me the dreaded 1211 Lambda code, so I used Ernie's and FBB's tip of wrapping a wire around the O2 sensor's metal frame, then using a hose clamp to secure the wire to the O2 sensor-frame, then I wrapped the other end of the wire underneath a 13mm bolt on my tranny where the factory had already installed an extra ground strap for the oil temp/pressure electrics.

Reset my ECU's.

Poof! No more 1211 error code.

Honestly, if you have the 22mm O2 sensor socket tool, you could swap out the O2 sensor in 15 minutes. You don't even have to disconnect anything on the air filter or move the air filter...that just helps you do the job without snaking your arm underneath that area blindly.

Hit the old O2 with "Liquid Wrench" (accept no substitute!) the night before and it won't take anymore than 1 hand on your ratchet to break the old O2 sensor free from your 348's cat.

The Bosch sensors are packaged with O2 sensor-safe thread anti-seize compound, the cheaper (but superior performance) Borg-Warner O2 sensors ($25 each, a real bargain) don't have that anti-seize...and you need to use "Sensor Safe" anti-seize on them. Your local parts store will sell it to you for less than $1.

You'll feel great for doing the work yourself, though it might not save you much if you have high value assigned to your own time. You're probably looking at $350 total in parts/labor at a Ferrari dealership for this job, versus your time and $40 ($25 + $1 + $14) in parts to do it yourself (though you save the time of taking your car to the dealership and later picking it up).

To me, it's well worth doing yourself. In reality you are just unscrewing one 22mm bolt that just happens to be called an "O2 sensor." Thanks, No Doubt

 *a generic 22mm O2 sensor socket tool will fit your 348's O2 sensor

 Ernie's way to change O2's without the O2 sensor socket:

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 Removing The 348 Airbox
removing the inlet tubes from the air box:
airbox tube
airbox tubes

Then you need to remove the air injection tube on the bottom front of the air box, just under the mass air flow sensors.

Loosen the clamp that holds them in place, and then wiggle both of them off:airbox clamps
air injection hose

Next you will need to disconnect the mass air flow sensor from the air box. You can do this like I did by removing the little screws on either side of the mafs and leave them connected to the tubes running to the throttle bodies. Or You can loosen the claps holding them to the throttle body tubes and leave them connected to the air box. This time around I disconnected them from the air box:maf

Okay now remove the four 10mm nuts that hold the air box to the subframe, double check that everything is disconnected, and then remove the air box:unscrewing 10mm nuts
removing airbox
Thanks, ernie!

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Here is a list of what you need to check:
Gas cap.
Fuel rail connections, especially if it is a 355. If they are over tightened they can crack.
Connections on the fuel filters.
Gas tank fill hose:

Make sure that the rubber isn't cracked or leaking. Verify that both #31 (see below) hose clamps are sufficiently tight (but not choking the hose).

Gas tank overflow hose. Same deal, make sure the rubber isn't cracked or stopped up. Verify that hose clamp #35 (see above) is sufficiently tight (but not choking the hose).
Vapor lines going to the charcoal canister:
Connections on the fuel pressure regulators. Thanks, ernie

To check the connections that Ernie lists above, use your finger. Rub your finger under and around each fuel line connection (e.g. at the front and back of your fuel rails, top and bottom of your fuel filters) and then smell your finger.

When your finger smells like fuel, then you've found at least one leak. Loosen that connection (remember to place a rag underneath to catch spilled fuel), wrap the threads with 1 layer of fuel-safe yellow (not red, not blue cannister) teflon plumbers' tape (coating threads with liquid teflon is recommended for those who don’t like teflon tape), then re-tighten.

Wipe the entire area concerned with yet another (it's important not to re-use a rag here so as to avoid tainting the smell) rag, and dispose the rag so as not to confuse yourself with fuel smells.

If you don't have a fire extinguisher rated ABC, then get one before you next start the car.

Likewise, turn the ignition key to the Run, not to the Start, position to see if you can find any (more) leaks after your yellow fuel-safe teflon-tape repair above.

Once all of your connections have no fuel smell with the ignition key in the Run position, then start your car and recheck all connections again with your finger while the engine is running.

No Doubt

Try this simple thing if you still smell fuel....take the gas cap off...if the rubber gasket is in place then lubricate it well with brake NOT use any other kind of lubricant. I had a gas smell develop on my 348 Spider which the dealer could not solve even after inspecting all hoses and replacing the flapper valve near the top of the system (at considerable expense). This brake fluid "fix" was suggested by Jean Louis Lebretton of Le Mans24 in Cos Cob CT and it worked. Thanks, VinnyCar

I smelled fuel in my 348 when I first got it especially when the tank was full or when I did corners. Took a lot of trouble tracing the trouble. In the end, it was an "overflow escape valve" (not sure of the correct name) near the fuel cap that was stuck and needed to be cleared. Thanks, SFChallenge

CF355 does point out, however, that the more open cloth-type performance air filters (e.g. K&N) will naturally vent a small fuel smell after a hard run, detectable in closed areas such as a small garage. OEM paper filters don't vent gas fumes, however.

A bad spark plug, spark plug wire, coil (or coil connection), bad catalytic converter, or bad O2 sensor can also leave a detectable smell of fuel in the vicinity of the catalytic converter area.

Loose exhaust header (to manifold) bolts can emit a fuel/exhaust smell, too.

TIP: to remove the smell of fuel from your hands, rub them with fresh squeezed lemon juice.

Unique 355 Fire-Prone Areas

Unique 360 Fuel Smell Areas

Unique Testarossa Fuel Smell Areas

Unique Mondial Fire-Prone Areas


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The major electrical issues on most Ferraris are:
1. bad connections (typically fixed with Stabilant 22a)
2. Bad/insufficient grounds (e.g. most Ferrari alternators need a large dedicated ground strap)
3. Failing car battery
4. Failing alternator system
5. Corroded or burned or otherwise failing relays
6. Reverse current that is traveling backwards through dash bulbs that have burned out

Use Stabilant 22a for all of your electrical your connections. Insure that you've got an adequate ground strap for your car battery and for your alternator.

Insure that you have a decent car battery (e.g. a new Optima yellow top). Insure that your alternator is giving enough amps in its output under load.

Replace any of your electrical relays that show exterior corrosion/flaking/oxidation (for the metal ones) or heat scarring/burn marks for the plastic-shelled ones.

Common intermittent radiator problem that I never bother to chase until it reoccures after first replacing the fuse... ram effect water from driving in the rain or washing car will cause a heavy draw and blow a radiator fuse. Most common real problem that I have found if they continue to blow a fuse is high resistance at the relay plug in the foot box. Clean the radiator relay male pins with a scotchbrite pad then treat with Stabilant 22a (or replace with a new relay). Thanks, DaveHelms

Replace any failed dash bulbs with one-way LEDs.

Sam's Club sells their NASCAR battery (Optima yellow top under another label) for $99.

MOTORS: All Ferrari (electric) motors can be rebuilt by your local magneto shop (every town of any size has at least one).

I finally found a place to rewind my armature. They did a great job for $55. I thought I would post it here for reference.
Holcombe Armature Co.
905 Rockmart Rd.
Villa Rica, GA 30180
770-459-5544 thanks, Drew Altemara


 Steering/Light Stalk Switch Repaired 

 Battery Drain

It's fairly common for a parked 348 to drain the battery over a period of time of as little as two weeks, but it doesn't have to be that way. It's relatively quick and painless to track down the usual electrical culprits. First, have your favorite auto shop install an ammeter (amp-meter) inline with your battery and easily viewable (or if you know what you are doing, you can buy an ampmeter from RadioShack and install it yourself).

Now with your engine off and ignition key removed, note the amp (current) draw on your ammeter.

Next, pull out half of your relays/fuses from your fusebox in the passenger footwell. Again, note the current draw. Then remove your remaining fuses/relays and note the current draw.

At this point you should know which half of your circuits are drawing the most current when your car is supposed to be "off." Re-insert half of the fuses/relays of the group that drew the most current previously. Note the current draw and continue with this process of pulling/inserting half of a group until you have narrowed down your problem circuits.

Repeat this process for the fuses/relays under the felt liner of your luggage compartment up front. By following this process you will quickly identify your problem circuit(s), showing you which part of your 348 needs anti-corrosion fluid, wire-brushing, Stabilant 22a, and perhaps even new components.


RELAYS: The metal encased Bosch relays in the fuseboxes and ABS panel should be treated as finite service life items and routinely replaced ahead of failure. It seems as our cars age, the construction of the original relay and fusebox allows moisture and trollage to come into the relay. To illustrate the point, the inside of your relay can be estimated by the condition of metal on the outside via the surface deterioration. And in DC circuits, it does not take much outer surface change to effect/predict internal connectivity failure. Thanks, Russ Turner

NOTE: Bosch 0332014113 relays have now replaced/superceded the older Bosch 0332014140 relays (same circuit diagram on both). There seems to be a general consensus as a good idea for replacing the two old 0332014140 relays for the left and right fuel pumps (found in the passenger footwell) as well as replacing the two old 0332014140 relays for the left and right fuel injectors with the newer (and cheaper!) 0332014113 relays. They are cheap at .

Ferrari 348 Relays ~$5 each (thanks 91tr)

Breakers that can replace fuses



7 isn't used, marked as "available"

Bosch relays (as used on Ferraris and various other makes of cars) number their metal pins with a standard category system.

PIN # = Standard

15 = Switched positive output from battery
30 = Postive output direct from battery (+)
31 = Direct to battery negative ( - ), ground
31b = Return to battery negative via switch or relay
49 = Positive input for turn signal flasher
49a = Turn signal flasher trigger power to switch (54); marking used after /5
54 = Turn signal switch contact from flasher (49a); marking used on /5
85 = Relay trigger wire, generally for negative/ground winding on electromagnet
86 = Relay trigger wire, generally for positive winding on electromagnet
86a = Path to ground via neutral switch with diode (prevents "NEU" from lighting via clutch switch [contact 86] )
87 = Normally open relay output, generally
87a = Normally closed relay output
87b = Second normally open relay output on a seperate throw
D+ = Voltage Regulator/Dynamo (Alternator) positive
C or KBL = power to turn signal indicator light in gauge cluster *thanks, Airheads BMW club Joe Cuda

 Here's what you do to test the oil cooler fan - very simple (and this procedure is valid for using on other Bosch relays such as the fuel pump relays, see chart above).

Pull out fuse 15. It's the third one (see picture above) from the right in the lower row (20 amps). Make sure it isn't blown, and put it back in.

Pull out relay "O". It's the center one in the bottom row in the footwell panel.

There are five slots in the relay panel for the five terminals on relay "O". Take a jumper wire with two male spade terminals and jump the two positions shown in the picture (top center to bottom center, terminal 30 to terminal 87). It doesn't matter whether the ignition key is on or off.

As soon as these terminals are connected, the oil cooler fan should come on. If it doesn't, then there is a problem either with the wiring, the fan, or the ground. If it DOES come on by jumping the terminals, but never comes on any other time, then we can look at some other possibilities.

The thermoswitch for the oil cooler fan should close at 90 degrees C, turning on the fan, and open again at 80 degrees C, turning off the fan.

There is normally no power running to the thermoswitch or to the fan motor, so don't check for power in the back. Thanks, Miltonian


ernie and TmobileGuy: Window motors "slow down" for those last few inches? Then you need to adjust the window guide on the door. It is the little black (irregular) oblong part at the side edge of each door. When you open the door you will see two black allen screws above and to the side of the red door light. Loosen those when the window is down, then raise the window. Now tighten the two allen screws back down. Your window should now raise and/or lower a bit faster (don't expect miracles here).

Details About the 348 Interior, Leather, Vinyl, Plastic, Wiring, Radio, Speakers *Thanks to Jeff Burk

348 Door Trim Removal (Thanks, Dasadrew)

348 Door Wiring Connection Repairs (thanks sweetpotav)

 (AMP door wiring connector)

 (AMP door wiring diagram)


Erratic headlight/dash light behavior (e.g. dash lights remaining on after ignition key removed):

You've got current flowing in the wrong direction in your dash. This can happen for a variety of reasons, not limited to:
crossed wiring, burned out dash bulbs, bad ground connections, bad battery ground, bad battery, bad alternator/diode, bad relay(s), bad turn signal/bright light stalk, bad ignition switch, etc.

If the car has *ever* been jump started, then yank your battery out and replace it with a new one. That may, repeat, may save your alternator and might even cure your electrical gremlins.

If your dash lights are stuck on (when you've already removed your key from your ignition), then open up your foot panel to expose your fuse/relay panel in the cockpit., remove your relays one by one until your lights go out (re-install that relay and check to see if any other relay also solves your problem, ad nausium). This should narrow down which circuit is problematic.

Next, remove the 2 phillips screws that hold your black driver dash pod to the dash. Turn the pod gently around, unplug each wiring clip, and apply Stabilant 22a liberally to the metallic connections. Repeat this process for each bulb in your dash pod, too. If you have any dash lights that are burned out or very, very dim, then replace them (preferably with LEDs because LEDs don't allow current to flow in reverse). Plug it all back up, put it back on your dash, tighten down your 2 phillips screws, and see if that solved your problem (verify that all dash bulbs/LEDs work).

Finally, apply liberal amounts of Stabilant 22a to the rotary ground disconnect switch that sits above your battery (as well as to your battery contacts themselves).

Disconnect your battery for 30 seconds. Now start up your 348 and DO NOT TOUCH THE THROTTLE until after your engine has heated up enough to turn on your radiator fans. This will give your A/F ECU's time to relearn your car...a process that generally solves many, many 348 problems (and is free to try).

By the way, your passing flashers only work when all of your lights are off. Likewise, make certain that your green "parking light" button on the center vertical console is not pressed in/activated.


 Alternators and Voltage Regulators

348's have a battery light/picture in the bottom center/right side of the driver's instrument pod. When driving, this light may come on to indicate that the alternator has died and is no longer charging your battery. You can still drive your 348 for a few miles, but soon you will be stalled on the side of the road if you take no positive action. You were warned!

That being said, your 348 may also warn you of a failed alternator before you even leave your garage. Bee Jay reports that his 1992 348 TS had no battery light with his ignition key in Position II (Run) prior to starting up his car. Normally, your 348 will display *all* warning lights (including the battery light) with the key first turned to Position II prior to starting (this allows you to see that no bulbs have burned out).

However, with a failed alternator, at least in some cases your battery light won't illuminate for that light-test prior to starting your car. Again, consider yourself warned if you don't see your battery light prior to starting...your alternator may be bad and you may be running solely from your battery power (which will be short lived).

Also, please note that this is a known case of a time when you will *not* see the battery light come on while driving. Instead of the normal alternator warning via the battery light coming on while driving, if you don't see the battery light prior to starting, then you won't see it while driving (even if the alternator has failed). Thanks, Bee Jay!


Complete pictorial step-by-step 348 alternator removal, rebuilding, and replacement (Ernie rocks!)

(Ernie rocks!)

For the rebuilding of your 348 alternator (348 models use two different alternators based on year - Delco and NipponDenso), you might consider using some copper heat transfer compound between the rectifier heat sink and housing for better heat transfer and electrical contact.

Quicky Alternate Version: How to remove a 348/355 Alternator: I removed my alternator to replace the alternator belt.......there are no special tools required, just metric 10, 13, and 17mm tools are needed, plus an 8mm hex key.
First, disconnect the battery. That's important. Then you loosen up the belt tensioner (take note of the belt tension so you can re-tension later), remove 2 bolts on the alternator (disconnect the wires on the alternator) and down she drops. *Thanks to cf355, spaghetti_jet, Chris Fricke

F355 and 348 Alternator Issues

Mondial T, 348, and F355 Alternator Replacement

One potential Mondial T/348/355 replacement alternator, new from NAPA, part number is 13-4553. The Delco part number is 10479969. GM part number: 1101267 Cost: $144. The regulator is "made in Costa Rica" and has 35-127-7 0107-7 on it, the rectifier says CARGO 131880 M090 RD-02T A14938. The newer, cooler-running "iceberg" version is here. That unit may require the universal braket adapters sold on the same site.

JM3 reports that this (pictured) regulator is superior to OEM (INR734P REC ND):

I already had one alternator melt down, replaced it along with the battery. Now the tell-tale battery light is coming on again and the tach is going nuts at higher RPM - the signs of impending alternator doom. I just went through the archives and it looks like Elreg has the parts for the Delco. If anyone is interested in doing a Delco rebuild here are the #'s: Elreg website Rectifier: 311-618XHD Regulator: 101-670HD

"The only difference is the B+ stud is 6mm instead of 8mm. Apparently I can swap B+ studs. Other than that, a direct bolt-in." thanks, 3forty8


NipponDenso: USI part number for 348 Alternator Rebuild:
improved regulator - #
00632, 71-30003/SCP

NipponDenso: Regitar part numbers for 348 Alternator Rebuild:
regulator - #VRH2005-4A
improved rectifier - #

Voltage regulators on alternators rapidly burn up if the ground or positive connection to the battery is/are bad (hat tip: Ken and RoloCR). For 348's and F355's, the obvious first place to check is the "battery cut off" AKA "battery disconnect" switch. Both ground cables can be attached to terminals on the same side of this cut off switch in order to bypass it (in case the cut off switch is making a bad electrical connection).

After bypassing the cut off switch, check the heavy cables at both the junction box in the rear (engine bay) and under the dash in the (U.S) passenger foot box? Remove the COM bar and wire brush it, inspect the plastic housing for distortion / melting. Found problems here numerous times. Thanks, davehelms



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348 Jack Points (thanks to Jim Riggs)

Ferrari 348 aftermarket (stronger than OEM) front and rear bumpers from $1,600 are here:

And here:

Spoiler Repair

Can The Front Bumper Top Trim Piece Be Unscrewed/Removed?

An excellent example of rebuilding/repairing a broken 348 front bumper (with Kevlar and Fiberglass) is here: 348 Bumper Repair by Dave Cochran


348 Front Bumper Removal:

1)Remove the trunk liner. You will need this out so you can access the four bolts that hold on the front.
2)Take the two front tires off, then remove both front fender wells. These have to come off so that you can unplug the side maker lights, and to loosen the four bolts, two on each side, that hold the bumper in place on the sides.
3)If they are still on the car, remove the airdamn covers, that go from the bottom of the bumper to the wheel wells.
4)Now that you have all the bolts loose slide the bumper off some but not all the way. This will give you a little bit more room to get your hand up under the bumper to disconect the plugs for the fog lights and turn signals.
5)Remove the bumper. You will see two L-shaped rubber pieces, on the back of the bumper, with some metal spacers on the bolts that you just slid out. You can take those off, so they don't get lost at the shop.

A few tips. After you have the bumper off, while it is still fresh in your mind, put the screws and bolts back in the holes and on the bolts they came from. This way you don't loose any. Also when you go to put the rubber pieces back on, the L goes on upside down and the bottom of the L points out, toward the side of the car. *thanks,

Rear Bumper Removal

 photo by eric355

photos by Stevew

Do It Yourself Carbon Fiber Tutorial (thanks, Paul348)

Carbon Fiber Cloth and Tape and Resin Supplies!


Common 348 and 355 Space Frame Cracks/Breaks NOTE: These frames are *steel* on all 348's and 355's. Steel can be inexpensively welded, and additional steel plating can even be added (if desired) at the two major (in rear) weak points. In other words, spend $120 for a proper weld (just remember to disconnect your ABS ECU, Exhaust ECU's, A/C ECU, and A/F ECU's prior to applying the torch) instead of spending $12,000 for an OEM replacement space frame.

 *Eugenio's Ferrari 355 space frame crack repair. Note the black metal plate that has been welded onto the Ferrari sub-frame in the center of the picture. This is repeated on all four sides of the frame rail that had the crack. By welding this "box" around and to the cracked OEM rail, the frame gains is now stronger than it was when new!


Black body stripe

*thanks, Jack Russell Racing

You can also go to a body shop supplier , it is 3m body seam sealer . 3m numbers are 08364 or 08500. Thanks, MDShore348

Carbon Fiber Door Sill Install *thanks, F355Berlinetta


348 Racing Harness Info


Gas Tank Lid/Door Fill Cap

Won't stay closed or pops open on its own: check emergency/backup release cable just inside the engine compartment (near the gas lid, next to the left shock tower). This cable must be manually pressed back in so that no cable is exposed (see picture). When you pull out the handle in the engine compartment, it doesn't retract all the way by itself, you have to push it fully home. If it's part way out, the plunger does not extend all the way to keep the door shut, even though the electrical mechanism is working fine.

It won't work properly if the handle is part way out like this - push it in! *thanks,


GeorgW reports that mechanical re-adjusting of the door itself and the plastic plate (which connects to the plunger) can also solve the problem.

 expresscat39 reports that you can use some strong two-part epoxy to re-affix your gas lid/door if it ever falls off.



The $0.50 gas door hinge-spring fix

 (hint: it's just a mouse-trap spring)


Outer 348 Mirror Disassembly (Thanks, Miltonian!)

348/355 Mirror Mount Fix (Thanks, Terry)

From this:

To this (use a banjo bolt from a hydraulic supplier for $6):

Full Door Mirror Disassembly/Repair (thanks, Dasadrew)


Center Mirror Replacement/Move/Upgrade

I bought a mirror from Kragen (I picked one that was thinner than the original); used Goof-Off (the solvent a lot of guys on here use for the sticky parts cleaning) and a trim removal tool to gently pry off the original mirror. I pryed at the original mirror with the trim removal tool as I worked Goof-Off into the back of the OEM mounting plate. As wingfeather found out a good yank removes it. Then I cleaned the area with an alcohol wipe to remove any remaining residue. For the life of me I can't recall what bonding agent I used, it is the stuff they sell at Kragen right next to the mirrors. I also removed those annoying seatbelt turds (not sure of the technical term) in the headliner that are supposed to hold the belts up when you enter/exit the vehicle. That allowed me to place the mirror quite a ways up the windshield to greatly improve visibility. The most important thing to have on hand is a six-pack of beer to calm your nerves so you don't think about how much it will cost to replace the windshield if you muck it up...

thanks, 3forty8


Door Latch

Part #53 above (white plastic) often breaks. It's a common plastic automotive cable retaining clip (same as for all Chrysler cable latches as well as Ferrari 348, F355, and 360). It's Ferrari part #63291200. You can get it here for $0.45. Pep Boys calls it a "door lock rod clip." *thanks, Miltonian and Oper8

ernie reports that an improved version is the same clip in nylon from Audi.


You can open stuck doors on a 348 from the outside when the window is down, using a long slotted screwdriver. Look down inside the door, at the rear, in the area of the door latch, towards the outer side of the door. If you look carefully, you can see where the cable from the inner door release handle runs straight upward into the latch mechanism. If that cable is attached correctly on each end (chances are that it isn't), then when you pull UP on the inner handle, the cable pulls DOWN on the lever on the latch. By reaching inside with the screwdriver, you can push straight downward on the same lever, and the door will pop right open. I just did it on my own 348 to be sure.

Once you get the door open, you will need to remove the panels to find out why it isn't opening correctly. Chances are that the linkage has just come unattached.

*thanks, Miltonian


348 Door Wiring Connection Repairs (thanks sweetpotav)

(AMP door wiring connector)

 (AMP door wiring diagram)

348 Door Trim Removal (Thanks, Dasadrew)

348 Door "Popping" Noise

1. Open the door
2. Disconnect the wiring buckle from the door jamb (just to allow room to work)
3. Using a punch, pound the exisiting pin out, from the bottom up. It takes a little time, but just be sure not to hit any paintwork!
4. Once the pin is basically out, use a needle nose pliers to remove it entirely. My old pin looked nothing like the new one: old pin was probably a single wrap of steel and fell apart as I needle-nosed it out. New pin was several wraps of steel, and much more substantial.
5. From the top, insert new pin.
6. Using a punch tool and a carefully swung hammer, drive the new pin into the hinge.

No more popping sound!

$1.80 (replacement pin #8 in diagram below left) from Foreign Cars Italia in Greensboro. Part number 65859300, and it's fixed. -Daniel Pass

NOTE: the F355 diagram at right below uses a screw (#8) rather than the 348's pin. This screw (#8) and nut (#43) may be a desirable upgrade for 348 owners.


348 Door Vents/Grates/Louvers Removal

I've removed the door grates today and there are no screws under the door handle. Only the 4 Screws on the 62118310 grates/part itself and two 10mm Nuts on one end of the grates (inside the door to the front, by the hinges). 5 minutes of work. *thanks, Samy


348/355 Hood/Hatches/Bonnets

Both front and rear hoods/hatches/bonnets for the trunk and engine compartment have primary and secondary reserve cables to open those compartments. Thus, if one cable breaks, you can still access your front luggage or mid engine.

The reserve cable to access your engine is hidden inside your gas tank lid compartment.


For your front luggage compartment, there are *two* reserve pull cables, one on each side of the car, under the dash, near both doors. Each pull cable opens 1 front latch, so both reserve cables must be pulled to access your luggage compartment.

 pic by Notbostrom

If your latches are stuck, then try getting someone to push the bonnet/hatch down as you pull each lever. You push one side down with one hand and pull the lever with the other. And have some one push down the other side at the same time...thanks, chaa

Underhood Insulation Repair

Insulation Repair Part 2

348 Hood Struts for $30

The Sachs part number for the 355/348 engine lid and front hood struts is SG437007. has them at $26.79 $4.01 each for shipping. - thanks, DaveHanda

I still have the old Stabillis 348 hood strut, so I took it to the Audi spare shop again and bought another one. Both ball joint ends including the shaft are chrome while the original are black. The body Cylinder is black. The make is "TRIDON" and the part number is 4B5 827 552D for the rear bonnet of the Audi A6 (C5) . It cost me another $33. Be warned that it is slightly fatter than OEM 348 and extra strong even with just one. If you change both, you might bend the bonnet trying to close it! Even with just one on the rear, I have to put a hand on the cover before I pull the level as it will spring up. - thanks, William Heung 


How To Change Hood Struts

First, prop open the bonnet with a long rod. This operation entails removing the support struts, after all.

There are the main two styles of struts. You'll have one or both (if a prior owner mixed types) on your car.

One has a thin wire "lock" that holds that round ball inside the black plastic cap on the end of the strut. The very end of this wire "lock" is just a straight little tip of metal, and it pokes into the black plastic cap on the strut to lock the ball so that the strut stays installed.

If you have this type of strut, then place a flat-blade screwdriver as shown in the picture in the link above and pull the little metal lock tip out of its hole in the black plastic cap. Then put your hand on the top of the strut and yank. Wallah! One end of the strut is off. Repeat as needed.

The second type of strut has a wider wire clamp. Insert your flat-blade screwdriver as shown in the link above, then pull/pry the wide metal clamp such that it moves away from the black plastic cap 3/8" or so. Then put your hand on the top of the strut and yank. Wallah! One end of the strut is off. Repeat as needed.

Easy peasy.


 Return To Index



348 door locks can be locked via the center console lock button, unlocked via the center console unlock button, locked and unlocked via the exterior driver and passenger side door key-holes.

There are two common faults, the locks both cycling up and down, as well as the locks going into the lock position briefly and then popping back up into the unlocked position (i.e. up). The latter is typically encountered when one or both doors is not fully closed. This is a feature of the 348, not an actual "fault."

If you open a door, push the lock on the door manually and then close the door, this seems to make the lock motor do it's up and down cycling dance (at least when the lock hasn't moved all the way into the locked position). In this case unlocking the doors with the key instead of the center console button should stop the locks' dance. Thanks, porkface

Alternatively, it may be due to adjustments because if I grab the lock button on the door and yank it upwards on the upstroke so to speak, it will suddenly stay in the unlocked position instead of cycling... Thanks, jkuk


My 308 did it. Turned out that the door knob was screwed too far into the door not allowing enough movement on the relay switch which made the relay go nuts. Turned out the original owner stripped the knob & that was the only way it would stay on the threaded shaft. One new knob later & all is well.

I've had the door panel off & checked this and the amount of travel by the door knob is very limited to activate the relay.

BTW: the panel was off today because the key would turn, but the lock wouldn't move. There's a small pin in the end of the lock that fell out so turning the key turned the tumblers, but nothing else. I suspect the pin went out the door's drainage hole. Until I find a used lock (a locksmith couldn't help), I used a piece of Romex ground wire cut down to the proper size. It was malleable enough to do the job. Thanks, clydeM


A broken wire or bad connection in the door connector (very common) can cause this. It was exactly this fault (plus a crackling speaker) that made me re-wire it. Thanks, Chrisx666


I had almost the same problem, started when the wife slammed the door, can't blame her, door seems heavy and people don't realise how easy it closes. Problem wasn't electrical, it was the lock/solenoid relationship a little out of whack. The unlock signal kept repeating because it thought the door was still locked,[I think] and it was. adjusted the linkage between the lock and the solenoid and all was solved, don't have the slightest idea why. As I remember, I had to turn off the battery to get the "psychotic" action to stop, drove home and all was well until I tried to unlock the doors again, then same thing over and over. I had to disassemble the door from the outside to get to the lock and fiddle with the linkage btw the lock and solenoid. got that right and no problems since. Thanks, Markie1949


i had that happen to me too , the first "bad" thing to my car i ever experiences , and it was around a group of people , i admit it was embarrasing... i got home pulled out my tool box, but i first manually rotated the tumbler with my key .. TADA, fixed. i think the door look gets half way and it doesnt have the balls to take it to unlock or lock mode. Thanks, MDShore348


I encountered a problem with my door lock on the driver’s side. The central locking mechanism locks both doors and both doors lock with the key from the passenger’s side. When I turn the key In the drivers side door lock it would just turn without locking the door. I figured it could be tumbler problem. So today I removed the inside door panel. The "C" clip in the back of the mechanism had popped off and there was a spring and a few other parts bouncing around. Thanks, amorepresto


If one door isn't fully closed, the locks will go down for you and then pop back up. Ferrari calls it the Monica feature. Ba dum bump. It might also be a faulty lock-logic unit #3 in diagram below (Ferrari pn: 139522) under your passenger fuse panel. Thanks, No Doubt

You may have a broken plastic linkage piece on the back of the lock cylinder on the driver's door. This would explain why there is no resistance when you turn the key, and it is a fairly common problem. Be prepared for a shock when you go to purchase this piece. The inner door panel can be removed with basic tools, again, there are good instructions here. Or the outer door panel (the "strakes") can also be removed in just a few minutes, and actually gives better access IIRC. Here are the contents of the "lock repair kit", item #7000655, cost approximately $140 from the dealer. It's the little red piece that breaks. It's also at least possible that the linkage arm has simply popped out of its socket. Thanks, Miltonian

You need to remove the door panel and take a look. When I had my 91 it was just the "C" clip popped off / wore out! Total cost 19 cents and 8 hours my labor. See diagram above #31 second from the left. Thanks, AmorePresto


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Removing rear Sale Panels

 Picture thanks to JJStecher

The center section has two long studs on the back that go through the firewall and have nuts in the engine compartment. Look between the plastic coolant pipes, a couple of inches outboard of the struts for the engine lid. Once you get the nuts off, you can slide the center panel forward, then I think you can get at the screws to take off the side pieces. Thanks, Miltonian


Air Vent, Console, and Dash Removal

Repair Tips For Fixing "Sticky" or "Gummy" or "Melting" Plastic Air Vents


348 Door Trim Removal (Thanks, Dasadrew)


Interior color can be tricky, I ordered 3218 Saddle from Leatherique using the GAHH color chart and the dye was lighter than the tan interior on my 92. There is another Saddle color called 3228E II which is slightly darker. Anyway, in the end I sent them an sample cut out from the seat to make sure I get the right one. Same thing happened when I tried to get Wilton III Carpet from Hirsh - none of their samples matched - I am having GAHH send me their samples but it can be hit and miss because of the dye lots. If you are replacing everything may not be a big deal though...unless you are the Concour type! Thanks, Jagbuff





Repair glass and plastic windows/lenses

Custom Plastic "glass" Fabricator

Replacement 348 Windshields and Door Window glass:

$1,300 U.S. 348 Windshield Replacement Stories

$30 Epoxy Fix For Windshields

Custom Windshield, Fog Light Cover, and Window Fabricator 

Email Windshield Price Quotes

Top Windshield Suppliers

SafeLite Auto Glass



Do Not Use This "Glare Buster" Product On Ferrari Windshields!



 ernie and TmobileGuy: Window motors "slow down" for those last few inches? Then you need to adjust the window guide on the door. It is the little black (irregular) oblong part at the side edge of each door. When you open the door you will see two black allen screws above and to the side of the red door light. Loosen those when the window is down, then raise the window. Now tighten the two allen screws back down. Your window should now raise and/or lower a bit faster (don't expect miracles here).

348 Window Wiring Connection Repairs (thanks sweetpotav)

(AMP door wiring connector)

 (AMP door wiring diagram)

Slow 348 Window Aftermarket Fix

Slow 348 Window Aftermarket Fix - Part Two

Slow 348 Windows -> Broken Motor Mount / Door Runner Fix Thanks, JJStecher

Bosch Window Motor Repair Pictorial

348 Windshield Wipers: Bosch part number for a complete set of the 500mm blades (20 inches) including the aero wing is: 3 397 118 561
Refills only part number: 3 391 014 603 (thanks, fnu_lnu)

348 Wiper Repair Tutorial (Thanks, Miltonian)

Wiper Washer(s) squirts on its own

Replace Ferrari part #50332402, the non-return valve (#21) shown here (thanks, Miltonian)

For our Mondial T Brother's: How To Repair/Replace Mondial Rear Windows (special thanks to Hetek)

 Return To Index



Pulling The 348 or F355 Engine/Motor

ernie's famous Two-Jack Method (long version):

To drop the engine out of a 348 & 355 is just about the same.

Here are the steps.

1) Take the car to a shop that can evacuate the freon from the a/c system. You will need it empty to disconnect the a/c lines.

2) Disconnect the battery, and the ground cables to the frame.

Disconnect the ECU's located behind the seats.

Lift the car up for access to the bottom. Then remove the covers under the gas tank, and the shift linkage. For the 355 you will also need to remove the under tray and diffuser.

Disconnect the shift linkage at the gear box.

Drain the oil, using the 12mm allen bolt at the front of the engine, and the plug at the bottom of the oil tank in the rear. DO NOT use the one on the bottom of the engine.

7) Remove the rear wheels, and rear wheel well liners.

Drain the radiators using the plastic drain screw, located at the bottom right corner of each radiator tank.

9) Disconnect the cooling hoses, and heater hose attatched to the water pump. They are in the middle, upper, front part of the engine.

Disconnect the fuel filters, fuel lines, lines going to the charcoal filter, and connectors to the evaporation system.

11) Disconnect the oil line to the oil cooler, and the line from the oil tank.

12) Disconnect the
brake lines.

13) Disconnect the line to the clutch.

14) Disconnect the
Hand Brake.

15) Disconnect the
A/C lines

16) Disconnect the
speedometer/tachometer electronic connection going from transmission to the connector, between the clutch line attachment and the charcoal canister, on the body. It is on the left hand side of the engine bay.

16.5) If you are using two floor jacks, you will need to
remove the rear bumper. If you have access to a shop lift this step isn't nessesary.

16.5a) To remove the bumper first disconnect the license plate light (and for U.S. cars the side marker lights). You will then need to remove the heat sheilds. Now remove the 4 nuts, two on each side of the bumper, located near the wheel well. Then remove the 4 nuts that hold the bumper to the frame, they are by the muffler, and remove the bumper.

17) Disconnect the bolts that hold the exhaust to the frame.

18) Remove the air filter box.

19) Disconnect the
throttle cable ----->

20) Loosen the twelve bolts, but do not take them out yet, that hold the subframe to the body, located at the front bottom of the engine bay.

21) Lower the car so that the engine is sitting on the engine dolly. You can get a 1/2 ton flat moving dolly that will do the job just fine. The kind that has four caster wheels on the bottom and carpet on the sides.

22) Now that the engine is resting on the dolly, you can completely remove the twelve bolts that hold the subframe to the body.

23) Remove the nuts, three on each side, that hold the shock towers to the body. But don't remove the nut that holds the shock in place on the subframe. For 355's you will need diconnect the ride adjustment motors.

24) Remove the four bolts that hold the rear of the subframe to the body.

25) Double check to make sure you have everything disconnected properly.

26) Raise the body of the car leaving the engine resting on the dolly. As you are raising the body feed the ECU cables through the holes. Doing it this way makes it much easier.

26.5) This step is if you are using the two floor jack method. After you have the body off of the engine you will need to rotate the engine 90 degrees in order for the shock towers to clear the bottom of the cross bar that the heat sheild is connected to.  

27) Roll the engine out.

If you are going to use the two floor jack method, you will need to make sure that the floorjacks have a lift height of at least 20"-21". Other wise you will not be able to get the car high enough to roll the engine out. Also make sure the you are using jack stands and wheel stops.

Happy wrenching. (
After I had everything drained and disconnected it then took me another 4 hours to remove the engine, and then about 5 more hours to put it back in. Alot of that is double checking your triple checks.)


Tbakowski's Method:

Remove the engine lid.

Working inside the car, slide the seat forward. Remove the leather covered panels on the bulkhead,both of them. Underneith you will find the ECU's for the engine. Unbolt the ECU's from the bulkhead, disconnect the computer and unplug the yellow and white connector.

The rest of the pull is fairly basic. Remove air box assembly, and exhaust heat sheild. Drain your fluids, disconnect hoses, throttle cable, vent lines from the oil tank, clutch line, brake line, parking brake cable, there are 2 small vac lines and 2 electrical connections that must also be removed on the left side of the engine bay toward the front of the engine. They are for the e.v.a.p system, also disconnect the cables from the "jump" connection point. Oil lines must also be disconnected from the oil tank and oil cooler. Disconnect the a/c lines. Undo the exhaust from the top mounting will come out with the engine.

Remove all the inner fender sheilds, disconnect the ABS connectors (white) and remove the overflow tube from the expansion tank which is clamped to the shock tower. If you are pulling this engine on the floor..remove the rear bumper.

Undo the 4 nuts on the shock towers, and I sometimes even remove the nut on the top of the shock along with the washer. This makes it alot easier to remove when the body flexes inwards during remove of the subframe. Undo all the other mounting points (12 bolts at the front of the car 6 on each side) and 4 at the rear, once you have the subframe supported. The ones at the rear you will see when you remove the inner fender panels. One bolt hole is right beside the cat(horizontaly) And the other is right above it (verticly).

When you start to lower the engine will hear all kinds of flexing noises..don't worry..keep going. The body will flex almost a full inch inward during the removal. I use a turnbuckle brace inbetween the shock towers to keep this from happening. It makes the reinstall very need to fight with it. As you are lowering..stop often to check noting is still attached to the engine, and all is clear. you are lower the engine must also work the wiring harness out of the firewall the over top of the fuel tank. Do this by lowering the engine about 3 inches at a time, and working inside the car push the harness towrds the engine. The hole they have in the firewall is a little difficult to work with because it is small and the harness connectors barly fit through the hole. They must be put through one at a time.

Hope this helps..


Pulling The 348's Engine Part 2 (30K Major Service Step 1):

The OEM gears of the cam belt drive pullies are plastic/nylon type stuff. Aluminum gear teeth on SKF bearing internals are sold here: Forza

 Engine Out Service Pictures thanks, ericzz

Yes you do need the water pump changed. Make sure that they also change out the thermostat. There is a clip on the top of the thermostat that has a week spot. The clip is held in place by two ears that are pinched in place. Over time these can break, and the clip will go into one of the radiators. I know this first hand. It is a pain to get out because you don't know what radiator it is in. When it happened to me I found it in the radiator just above the oil cooler. Make sure that they change the straight hose that runs from the water pump to the cross over pipe, that is under the intake plenum. Have them give you a copy of the measurements of the valve clearances, before and after they adjust them. You want this so that they don't charge you for adjusting 32 valves when, let's say, only 9 valves really needed adjusting.
Also: Keep your ALL of your old parts. EVERYTHING! The old seals, old valve shims, tensioner bearings, and especially the water pump.

To take out the engine yourself using two floor jacks you have to remove the rear bumper. First, just go to Home Depot, or any hardware store, and get a 1000 pound moving dolly. They are flat with four casters, the wheels are solid rubber, and two of the sides are wrapped in carpet. It cost me a whopping $19.95, plus tax. LOL. Then all I did was jack up the rear and center the dolly under the subframe so that the frame sat on the carpeted sides. The big ones, not the little cross beams, same for the dolly. Disconnected the shift cables, fuel lines, A/C, and ECU cables. Drain the fluids (oil, coolant). Remove the 8 bolts that hold on the rear bumper. Next I removed the rear wheels and splash guards and sat the car down on the dolly. I didn't use anything to hold it in place. The engine is plenty heavy and the weight keeps it still. Remove the retaining bolts, lift the car, and *presto*, now you can roll the engine out. The dolly's are so cheap, you could get two of them if you want to feel better. I used just one, and it held up with no worries. Total Time: 4 hours. Thanks, ernie

ShanB used multi-colored zip ties to help him remember where everything connects upon replacement... He used Ernie's two jacks method above and a little care. The car really does not need to be raised very high at all and the engine rolls out quite nicely once everything is disconnected. His Total Time: 6 hours.

No Doubt says to remember to have your A/C evacuated before you start this process, and to disconnect your ECU's if you plan on rolling the engine very far...additionally suggests using painters' masking tape and a red marker to label everything that you disconnect. Coat all electrical connections on engine with Stabilant 22a, too.

FatBillyBob says that you don't have to roll the engine out; that you can change the cam belt by simply turning the engine 35 degrees while on the dolly.

Here's a tip: So far the only challenge has been removing the idler bearing without damaging either the aluminum shield behind it or the pulley bracket. The problem is that there's very little room behind the bearing and most puller jaws simply won't fit. I read Ernie's tip about using a socket to leverage against and found a good quality two jaw puller with thin tips that fit perfectly. I used a deep socket with a washer on top as internal leverage for the puller. Thanks, ShanB




Engine Service


348 Engine Service Pictures (not mine) for the "30K" Maintenance (thanks, ghardt)

Pros and Cons of Non-Standard 30K Maintenance Tricks (thanks to Markie1949 and others)

Improved 348 30K Service Parts Package

FULL 30K Major Service Parts List:

1 cam belt
1 tensioner bearing
1 idler bearing
4 front cam seals
4 front cam seal o-rings
1 rear cam seal
2 cam cover gaskets (one for each cover)
4 rear cam cover gaskets
1 water pump or water pump rebuild kit
1 thermostat
1 alternator belt
1 a/c compressor belt
8 spark plugs
2 fuel filters
1 oil filter
1 air filter
4 radiator hoses (2 going to each radiator)
2 water pump hose (1 feed/1 return)
2 heater hoses (1 feed/1 return)
1 water pump to cross over pipe hose
1 feed hose from expansion tank to radiator return tube
1 hose from expansion tank to cross over pipe
1 oil tank plug washer

If you remove the bottom cover of the oil tank you will need the gasket for that
Inspect and replace spark plug wires if needed.

The amount of valve shims can only be determined after clearances have been checked. Then you will order the size/s needed. If you car is equiped with a charcoal canister, it will need to be changed if the car has over 50,000 miles on it.
You will also need oil, water, coolant, brake fluid, and gear box oil as these are flushed out and replace with new fluids. *thanks,


 Intake Removal (thanks, ernie, Miltonian, and others)

348 Engine Tear-down Tips

PT348 - Pulley Tensioners for Ferrari 348 & Mondial T - £220.00 per set

Idler Bearing: if you haven't pulled the idler bearing off yet here is another trick. Take a long socket, I think a 12mm will fit in the hole, or is it a 13mm, anyway a long socket that will fit in the hole that the bolt cam out of. Put it in the hole then grab the back of the bearing with the puller hooks. Put the tip of the puller, the part that is the screw, on the long socket. This will put pressure on the bearing, and not the bracket that the bearing is pressed into. After you get the bearing to the top of the socket, if you need to, put another short socket into the hole and pull the bearing all the way off. If you just try to pull the bearing off without doing this you could break the bracket that holds the bearing. My bracket was busted and I had to get another one to the tune of $115.00 for a used one. *thanks, ernie


Timing Belt


Area 1

Model All 8 Cylinder models

Bulletin n° 1215

Date: May 2004

Pages: 1
SUBJECT: Timing belt for 8-cylinder engines

For your information, all 8-cylinder Ferrari models, independent of the Model Year, must
have the timing belts replaced every 30,000 miles or every 3 years, whichever comes

For information on Timing Belts for 12-cylinder engines, refer to Technical Information
Bulletin number 1003 dated October 2002.


Warning Signs of Cam (AKA "timing") Belt Failure:

 *credit to Spirot for the 308 cam cover with belt residue photo

 NOTE: belts can fail by breaking, stretching, jumping off of a pulley, or by stripping their teeth (e.g. on a siezed pulley)

348 Top Dead Center (TDC): The mark on the pully isn't very accurate. The marks on the cam are pretty good. But the best way to get a true tdc is to pull the #1 cylinder spark plug. Take the plug out of the #1 cylinder the put a gauge in the hole. You can also use a long stick. Then mark were it stops rising, and were it starts to fall again. Use the middle of those two marks for your tdc of #1. It's kinda old school, but still the best way to get a true tdc on this engine. Thanks, ernie

Speedmoore says " If you don't have a TDC stop, you can use a long rod or a long screw driver to "touch" the piston through the spark plug hole. As you come up to TDC stop as soon as the screw driver stops rising. Make a reference mark with a sharpee or paint pen. Turn again, as soon as the screw driver starts to go down, stop, make another reference mark. Do this several times to make sure you repeat your ref marks. You are doing the crank and rods, so forget about belt tension. Once you have the two marks clearly identified, make another mark exactly in the middle of those two marks and you have TDC.

When you want to be really snazy, you can take an old spark plug, knock out the center and tap threads into it. Then take a long aluminum dowel, of correct size and thread it so it can go through the hold plug and down to the piston.

A good engine builder will do this even if the crankshaft is marked as they can be stamped a tad off too."

Mitch Alsup adds that "You tap the threads so you that can stop the piston at the same point going forwards and backwards (cams out of the heads). The piston will touch the 'plug at the same crankshaft angle from both directions. Set the goinometer (degree wheel) so that it reads the forward stop and the backward stop at the same number of degrees away from TDC. This is several times more accurate than the puch marks on a standard engine."




Inspecting 348 Cam/Timing Belt - Engine In

 First, I dropped a little bolt loosener fluid onto the 4 cam belt cover allen screws (#11 in diagram at left). 10 hours later one of my allen screws was in so tight that its little plastic post connection snapped off. I don't know when or why Ferrari made the change, but my 1994 Spider has cheap, black plastic inspection covers (#6 at left)...unlike the earlier pretty, hardy, aluminum cam belt covers. Well, 12 year old black Italian engine plastic gets brittle! Be gentle.

You can see that there is a tiny amount of belt residue inside the inspection cover (at right). Just enough to cover a single finger when I wiped it off after taking the two photos of the residue (17,000 miles on this belt). My belt guide is clamped down such that only a single unfolded piece of paper will slide between the belt guide and the belt. NOTE: You will want to insure that your flat metal cam belt guide is *not* pressed down onto the actual surface of your rubber timing belt! This inspection alone is reason enough to remove your 2 "cam timing belt inspection covers" for examination.

The tension on my belt is tight. I could barely get the belt to deflect up or down a quarter of an inch in between the two cam gears/pulleys. No cracks or grooves on the belt. Teeth bottoms and teeth edges are perfect. Ferrari did a nice trick with the cam pulley ledge being outside one cam pulley and inside the other, by the way. I dig it. Belt was smooth but not slick on the outside. All in all it was worth the effort to check. I expected more residue and more visible wear. I expected less tension to still remain. There is no way that this belt has stretched any troublesome amount, based upon this inspection. Also, my cam gear pulleys had *clearly* been punched with an awl through the inspection slots in the plastic cam covers. Both punched marks aligned perfectly with the inspection slots, too. This hints at a quality non-factory belt change operation in the car's past.

When you are taking off your cam belt cap covers for "engine-in" regular belt inspections, please consider a couple of tricks:
1. tie a rope around your 5mm allen wrench. I did and that trick saved me from a fishing expedition.
2. before moving your cam cap cover, but after removing your bolts, place duct tape over each hole (just during the inspection, not for driving). This traps the washers in their holes, which you will be glad that you did because you've really got to twist, turn, and snake the cam cap cover through, over, and under a variety of hoses and wires and such...which otherwise might cause those washers to fall out and down into the nether regions of your back engine compartment (see: fishing expedition, above).
3. Definitely use bolt loosener fluid on your allen screws before attempting to remove your cam cap covers.
4. Consider some sort of bolt post reinforcement while you are doing this job (e.g. duct tape). The plastic bolt-posts are brittle and can use a gentle hand and perhaps some extra reinforcement during actual removal of the bolts.

5. DO NOT CLIMB ON TOP OF YOUR 348's ENGINE, not even to remove these cam cover inspection caps. Weight and movement *could* possibly tear or crack or otherwise weaken your brittle old head gaskets (~~ $125 each, plus pulling your engine to replace) *thanks, No Doubt


Having just finished a 348 engine out service which first off makes me no expert but a few of my opions:
1.Pulling the fuel tank is not the way to do it .I think it would be a messy, dangerous job, and the entire engine comes out very quick to do the job the right way, anyway.
2.You can both check tension and adjust the timing belt from under the car . There is a hole in the timing cover with a 17mm bolt that is for the tensioner . If you turn the engine about half a turn nice and smooth by hand and then lossen the 17mm bolt to allow the spring to take over it will correct any slack in your belt, then tighten the bolt and you have retentioned the belt . This is providing you have a good clean tensioner shaft and spring not all bound up etc. As Ferrari says you can do this once!
3.You can inspect the belt for cracks and dry-rot by removing the upper cam covers but you can not assess the life of any timing belt with a visual inspection.
4.Lots of arguments on duration of life of a belt. My car 1994 19k I just did the first belt looked great no issues just paranoid. A belt has a life span over a time period. If I had a late model car with 150k miles but only 2 years old I would not be worried, but 15 years on any belt would worry me. (thanks, ERICZZ)


 What You DO NOT Want To Hear From Your 348 re: Metallic Sound At Idle (thanks Markie1949 and Miltonian)

Cam Seal Installation

You do crank the 348 engine clock wise if you are facing the front (crank/pulleys) end of the engine. That is the direction that the engine turns when it is on. Also, the engine needs to turn clock wise to keep the tention on the internal chain. You will see the timing marks on the cam and the cam caps. They are at the front of the cam, right behind the cogged cam pully. There are also marks on the back of the cam pully, and you can see them through the little vertical holes on the back of the top caps of the cam covers. But those only give you a general idea as to were the cam actually it positioned. *thanks, ernie

Engine Timing Bearing TSB

Front Cam Seal Leak Fix Technical Service Bulletin (TSB - early 348 models)

Might as well change all the seals while you're in there. There are 4 of them and in behined the seal is an o-ring that should be changed also. To change them requires removal of the camshafts. Not difficult, but you must becareful when retightening the cam down. It takes about an hour to change both seals and o-rings on one side. Obviously you need to remove the cam covers and the timing belt must be removed to do this. But you will be doing a major anyway so no big deal.

Are you sure that it's the cam seal and not the cam cover gasket leaking? It's very common for a leak at the cam cover to be confused of a cam seal leak. I would clean the area thats dirty and then drive around a bit and re-check. Cam seal leaks on earlier 348 are common though... *thanks,


When you change out the rear cam seal, a nice trick to get the new one in is to use the 26mm socket that you used to take off the pulley on the crank, to tap the new seal in place. It fits perfect inside the seal housing, and keeps the seal from popping up on one side or the other. You can also do this with the front cam seals.

A cam area leak could also be from the cam cover gasket leaking next to the seal, thus making it appear that the seals are bad. However I had the rear cam seal go bad on me. I changed it out, only to find that somehow it got folded over. When I put the new one on, I was extra careful to be sure that it didn't get folded. No more oil leaks for this kid. Thats right my 348 DOES NOT LEAK! When I put the gaskets on, I use a pen line of silicone along both sides of the gasket. Just enough to see it barely bead when the cover was tightend down. That and a dot on both sides of each of the the o-rings. So yes, the engine can be made leak free, mine is. *thanks, ernie


Replacing Cam O-rings (and fixing oil leaks) Without Removing Engine! can be done in situ, i had it done 2 months ago. You remove the camcovers, cut the o rings out,then spend a lot of time cleaning around the opening getting all the sealant out and flush it with power clean.
To put the new ones in you cut them with a very sharp knife and feed it round till you have both ends at the top and stick it back together with super glue,put the gasket seal over the rubber and bolt everything back together.
It takes time getting it cleaned out, it's done quite a lot over here and works fine. Mine were pissing oil, now they're as clean as anything. - Thanks, Andy Hls

There is a TSB which instructs you to enlarge the cut out on the gasket for the O ring so the gasket actually has a gap there. It also instructs you to notch out the ends of the O ring grooves in the valve covers with a small round file. The gaps are then filled with silicone and prevents the O rings from being cut at the mating area. Thanks, Rifledriver



348 Head - Bolt Torque Specs

The valve clearance should be on the engine lid. For some reason I do rememebr the torque of the heads, you will need a dial indicator and the proper tool to be able to get at the head nuts.
The torque spec is: first tighten all head bolts to 60Nm or 6kgm. Then go back and tighten all nuts another 90 degrees. And thats it. Be sure to tighten them in the propper sequence else you will not get the correct clamping pressure for all cylinders and you could distort the head (worst case). Hope this helps. *thanks, tbakowsky

348 Valve Cover Nuts/ends Torque Specs

78 in-lbs....(6.5 ft-lbs.)
Best to use a 1/4" drive torque wrench.

For studs that are 6 x1.00mm thread pitch (common to most Ferrari engines), the torque figure should be the same, as the thread diameter and pitch are the same. However, the nuts and washers used on the cam journals are of a higher grade than what is typically used on the valve covers.

So...I use a slightly lower torque of 72 inch-lbs on the valve covers and end plates. It is very easy to over-torque the valve cover studs...and pull the studs out of the aluminum heads, so caution is in order. *thanks, David Feinberg

 *credit picture to Carlo Fabbrini



A very rough running 348 engine following a high-speed run can be a blown headgasket, with the roughness coming from coolant which enters one or more cylinders. *thanks, AR!


348 Leakdown and Compression Tests

348 Engine Leak Down Test Results and Compression #'s

On 348's the leak down should be <10% and compression between 180-185 for an ideal, perfect engine. Typical compression will be 160 to 180.

Leakdown of less than 15% should be an acceptable daily driver, track use if you want.

Here are a few thoughts on the matter:
1. Pull the fuel pump fuses when the tests are run. If not, fuel could leak down the walls and screw up the readings.

2. Open the throttle body plates much more than "idle" (they don't have to be wide open, but you don't want the tests to be performed with the throttles closed).

3. The compression and leakdown tests should be performed only on a *hot* engine, which is the most common situation for mechanics to insist on doing wrong. It's easier/safer to work on cold engines, after all.

Do you see dissimilar compression on one bank versus another (e.g. cylinders 1-4 have 178 while 5-8 see 148)? Timing can be off in one bank, if so.

Most people don't know that leakdown is showing the condition of each cylinder, whereas compression is showing you that your valves are opening and closing at the correct times (i.e. "timing"). You get lousy compression with your valves open, after all! Air just flows out rather than compresses inside a closed box if your valves are open at the wrong times.

How does the car perform? If you have great performance, and if you see no undue amount of exhaust smoke cold or hot, then < 15% leakdown is acceptable, < 10% is great, < 5% is race-pro-tuned.

Timing can be remedied when you do your next belt service, essentially for free, as that labor is going to be performed at that time no matter what (e.g. dialing in your cams with a degree wheel).

Look for exhaust smoke on startup when cold. Look for smoke when accelerating hard. Look for exhaust smoke when hot.

If you don't see any reasonable amount of smoke under any/all of the three, and if the car performs well, then you are probably OK to drive it as is until your next belt service.

On the other hand, smoke with those numbers would possibly mean valve/cylinder work is required, which could vary from a top end job all the way to a full engine rebuild (prohibitively expensive).

Also, bad compression and valves cause poor idling, how does it idle?

Further: both leakdown and compression tests must be run at operating temperature. That can take time and it's a PITA on a hot engine. Throttle open or closed? Makes a difference. Therefore, many folks take shortcuts - or just do the tests wrong. Make sure that the mechanic doing the tests does them correctly. The difference between hot and cold or open and closed is often as big as the sealing-capacity error you are trying to measure!

The other thing to remember is that it is not the numbers you want but rather, what the measurements tell you. A dry compression test if good, tells you that the rings AND valves are sealing (at the right time). A bad dry test should be followed by a wet test (a little oil carefully added through the plug hole to wet the rings (only)). A good wet test after a bad dry test tells you that the leak is from the rings, not the valves. A bad wet test after a bad dry test tells you that the valves are leaking - and the rings may be leaking too.

I view leak-down tests as pretty useless as they test a static condition and infer a dynamic problem. If an engine passes a dry compression test, at operating temperature with the throttles set correctly according to the manufacturer, the engine is probably healthy leaving you to answer the question, "How's it run?" - thanks, rolindsay


Generic Leakdown Test Tips

You want to first run the engine to get it hot because metal/objects expand (only accurate way for a leakdown) and initally put no additives in the cylinders to alter the leakdown test (does your Ferrari normally run with a teaspoon of oil in the cylinders?).

With engine off, next take out all spark plugs for the test. Remove your oil cap, coolant cap, and crack open your throttle.

At Top Dead Center (TDC), apply compressed air pressure via a differential pressure tester through a spark plug hole and note the reading. You should be maintaining somewhere in the area of 90% of what you put in for a nice "tight" cylinder. More importantly, all cylinders should be within 5% of each other.

When rotating a cylinder to TDC, don't go past TDC and then back. That might appear to "fix" what would otherwise show to be a leaking cylinder.

If you have excessive leakage, use your ears to locate the cause. That compressed air has to go somewhere!

Pop the oil cap off and listen for a hiss (blowby from rings or worse), pop off the coolant cap and look for bubbles (headgasket or block problem), listen at the exhaust pipe (exhaust valves/seating/guides), and finally listen to the intake with the throttle cracked/butterfly open (intake valves). This will help isolate your problem and direct you to the proper corrective action.

That's why it's important for you to be there when the leakdown test is performed!

FYI: most leakdown testers have two gauges, a pressure regulator, manifold, & hose. One gauge shows the pressure being applied, and the other shows how much pressure the cylinder is holding. The difference between the two gauges is your leakdown. So if you have 100 psi on the first and 80 psi on the 2nd gauge, then you have 20% leakdown on that cylinder.

Exhaust Popping Can Sometimes Be A Valve Problem

Valve Cover Gasket Replacement and Oil Leak Fixes (thanks to Verell, RifleDriver, GTO84, Jerrari, and others)

Snap On does sell a valve removal "Tool, Overhead Valve" #GA318A. This is an impact type tool used with a soft face hammer, magnetically retains the keepers. This tool is sometimes on "extended" backorder. A SnapOn "C" type valve removal tool as used on American V-8's will also work. I fabricated a hard rubber spacer to cover the valve face from mats in my basement gym to prevent any damage to the valve face or soft aluminum combustion chamber.

As suggested by tbakowsky: To remove the below head surface valve springs, keepers etc I bought a craftsman long socket with an OD slightly smaller than the bore in the head. Cut a long rectangular slot in the side to allow access to the keepers. Compressed the assembly, removed keepers, released, and disassembled. Reversed the procedure to assemble. Worked fine. *Thanks, Spider348

Valve Clearance: .2-.25 mm for Inlet (.008" to .010") and Exhaust are .3-.35 mm (.012 to .014")*thanks, ernie

*note: Dale says you want the Inlet down tight towards the 0.2mm mark, but Exhaust needs more cooling so run closer to 0.35mm there.

ShanB says "To adjust the valves I used a feeler gauge set to map the clearances on a diagram. I then removed the camshafts and set them aside, giving easy access to the shims - they sit atop retaining buckets and are easy to pull straight out with the cams off. I removed the shims on the (ten) out-of-spec valves and measured them - using those measurements to calculate what size shims were needed to get the clearances within spec. I replaced the "off" shims with ones of correct thickness (some swapped, some new) then re-installed the cams using new seals and o-rings. I then lined up all the cam timing marks with cylinder #1 at TDC and installed the new belt. Then I installed the drive dowels on the cam sprockets after some slight adjusting, re-checked the belt tension and cam timing by running the valve train (clockwise) and re-measured the valve clearances. One intake valve still managed to get out of spec (the new shim thickness was larger than printed) and required the use of a tool to depress the bucket to swap out that shim."

EricZZ says " I used to be a BMW tech. The shim set up for Ferrari 348 valves is just like the old bmw M3 M5 M6 engine..."

If you are going to replace the oil seals and O-rings, don't worry about the tool for the valve shims, because you will have to take the cams off in order to change the oil seals. Once you have the cams off the shims are sitting inside cups that just slide off. It is easy to take the cups out, you can do it with two fingers. But before you take the cams off make sure the you have checked all your valve clearances, and then double check them.

ernie also asks: What has me puzzled is I shot for the middle, and ended at the tight end of the specs. For example on one of the exhaust valves the clearance was .381mm. The far end of the spec is .35mm, The old shim measured 4.089mm. So I calculated that I needed a shim with a thickness of 4.14mm to put the valve right in the middle of the specs at .33mm. But when I checked the valve after I put the thicker shim in, and the cams back on, I got a measurement of .305mm for the valve now. That is were I just don't get it. My math is right, so what gives?

And FBB answers: Well a couple of possilbe things. 1) if you or the PO is smart you put the numbered side of the tablet away from the cam so you can read it. 2) you have to look at the shim number AND measure the shim. 3) make sure you measure clearance at the base circle which is perpendicular to the head deck not with the lobe point straight up perpendicular with the ground. 4) If you are using a digital caliper you have to zero it before use every time for accurate measurments. 5) if you are using a caliper you really need a caliper with comparator points because the center of the shim could wear more than the edge. 6) when you measure with a caliper you have to pinch the shim and let go of it with the other hand. If you hold the shim and measure you can "cock it" and that will through you off a tenth easy. 7) make a drawing of your head on a piece of paper and wirte down the measurements as you go. Keep the paper orientation drawing the same as the orientation of the motor. This way you don't make mistakes in transfering the data. 8) There is stiction and clearance slop upon reassembly. You have to turn the motor a few rpms to make sure everything seats home then measure.


OEM 348 Cam Profiles:

Duration (in degrees) at clearance of:
.020 .050 .100 Lobe Lift (in inches)

- Intake 242 228 205 .362
- Exhaust 242 219 194 .324
*thanks, PMA1010

FerrariFixer says that "if you're desperate for more power, get a local cam grinding specialist to remove a little base circle (need to check piston/valve clearance but I'd GUESS 0.5mm would be ok)." He also notes that just grinding the intake cams would yield the most bang for the buck (and reminds to increase valve shim thickness by amount ground off cams).


Inlet valve opening 12 degrees before TDC and Inlet valve closing 56 degrees after BDC plus Exhaust valve opening 54 degrees before BDC and Exhaust valve closing 10 degrees after TDC is the OEM setup for 300 HP

Inlet valve opening 10 degrees before TDC and Inlet valve closing 58 degrees after BDC plus Exhaust valve opening 50 degrees before BDC and Exhaust valve closing 14 degrees after TDC is the OEM setup for 320 HP

Non-Cat cars
Intake Opens 14 degrees before TDC and closes 53 degrees after BDC.
Exhaust Opens 53 degrees before BDC and closes 10 degrees after TDC.

Cat cars
Intake Opens 12 degrees before TDC and closes 56 degrees after BDC.
Exhaust Opens 54 degrees before BDC and closes 10 degrees after TDC. *thanks, 348Paul/


RexRCR says "The process is straightforward. You need a degree wheel on the crank. Set to TDC. The cam gears are two pieces with a retaining pin between them. Holes in the parts don't line up perfectly, so rotating one with respect to the other allows the cam timing to change.

I'm going off memory, it's been 11 years since I did this. I don't recall the exact specs. I believe that you can change cam position in increments of like 2 degrees, it's not infinitely adjustable. Engine out is way easier."

Tbakowsky says that "you need dial gauges which sit on the valve shim. This will show you the exact time the cam lob starts to open the valve. You can see the degrees by looking at the degree wheel. Setting it to where you want it can be a bit of a pain in the butt on the 348 because of the singal belt set set up."

SpeedMoore says "Bring it up to the timing marks on the camshaft, which will/should be on no. 1 cylinder. Remove the spark plug from no. 1 and put a TDC stop in to degree the crank in at TDC for cyl no 1. You may see a small hole at the toothed wheel for the ref and tdc sensor. This will also be in conjunction with the gap at the TDC sensor around 8:30 position. It lines up right with no 1 on tdc straight up and down in line with the cam drive sprocket. But I verify with the tdc stop. If you want to be 100%, install a degree wheel onto the crank dampner, setting 0 degrees straight up vertically and align with the case. You can use a piece of welding wire as a pointer and bolt on to point to no.1. This is certainly the only way to time if you want to adjust "retard, or advance" the cams different from factory specications.

The firing order is 1,5,3,7, 4,8,2,6....every 90 degrees

So, 1 & 4 are on the same mark as is 5 and 8 as is 3 and 2 as is 7 and 6. Make sure you are on no 1. to start off with. If the timing marks on the cams don't line up with no. 1 at TDC, you need to correct that. You should be able to put them exactly on their marks at TDC. Also make sure you replace the o-rings behind the washers of the camshaft bolts."

Take the cams out only after measuring your clearances. Keep the tappets and shims together and make sure the tappets go back in their respective bores. Write down with a sharpee your clearances and measure each with a micrometer. You may be able to move them around to get the clearances and only have to buy a few shims to get your clearances in the correct range. Hope that helps. Also, make sure you use a good sealant, like Dow Corning 730 when you install the valve covers back on. It makes a big difference on keeping oil leaks from coming back prematurely.

Mk e says "On the cams, I don't want to speak for anyone else, but the point I'm talking about is 1/2 way between opening and closing. I just put a degree wheel on the crank and an indicator on the valve. I look for about .020" inch motion opening and note the crank degrees, then I go unit it's .020 before closing and not the crank again. Split the difference and that is the lobe center. As a very general note of thumb, 110, 110, which gives a 110 lobe separation angle are a good place to start. The separation angle may drop to 105 in an NA engine and go to 114 in a boosted engine, but they're all pretty close."


Runaway Idle and Stalling:

Check the free things first...such as that there isn't something physically touching your throttle bars and cable under the hood (easy to see and touch when you open the rear bonnet lid). Verify that your throttle linkages and cables aren't covered with oil deposits and dirt.

Then apply cable grease to your throttle cable in the engine compartment and beneath your center console (it's just two screws under your ashtray and two screws on your shift gate to allow you to lift up that piece...well, that and you may want to unscrew your shift knob by twisting on it).

If that doesn't fix it, then unscrew the two or so screws that hold down your accelerator pedal box. Often there are rocks and various things that accumulate there and cause havoc.

If **that** still doesn't fix it then I'd attempt to unscrew/adjust your idle adjustment screws in the engine compartment (see section below).

Also, do check the little nonsensical things such as that your air filter isn't clogged/blocked. Add a good upper cylinder lubricant and fuel injector cleaner such as Techron to your fuel, of course, as well.

That really gives you an easy 6 separate and distinct chances to fix your idle at home before you start spending money and shop time away from your car.

And even then, I'd go for new fuel filters and new O2 sensors first before getting the Shop too hot and heavy into the car. Can't hurt to have those new parts on, and there's always the off chance that their simple replacement will fix a problem here and there.

Beyond all of that, should you still have a problem, I'd suggest applying first a good electrical contact cleaner and then second the
Stabilant 22a product to the electrical contact pins under the black data cable lines that go to both MAFs on the far side of your airbox.

I applied Stabilant 22a **everywhere** on my 348 Spider...all of the Ground connections on the chassis, all of the electrical connectors...hall effect sensor connection...fuse boxes (every fuse!)...everywhere current and/or data flows (even to the pins on my ECU's). That's yet another "can't hurt" step that tends to fix and/or prevent numerous 348 electronic issues.
*thanks, No Doubt

Engine Stalls

348 Stalls during normal drives or normal stops (thanks, Miltonian)

348 Stalls During Normal Driving, Part 2 (thanks, Ingenere)

348 Stalls at idle or when coming to a stop (thanks, vtc4198)

The master tech Tom Jones from solved my problem.
Here are his instructions!
Email 1
Adjust the air bypass screw #4 shown below. All you have to do is use a 14mm box end wrench to loosen the lock nut #3, Then use a straight blade screwdriver to turn the screw #4 out one complete turn. Now re-tighten the lock nut #3 while simultaneously holding the screw #4 in place with the screwdriver. Do this to both throttle bodies.

If that does not work.....(mine took email 2 to fix the problem)
email 2 - same as email 1 but with the ECU reset process

Turn both throttle body screws out one turn, then reset the A/F ECU's by shutting off the battery for 1 minute, turn the battery back on, without touching the throttle start the car and let it idle for 15 minutes before driving again.

One full turn on each idle air bypass screw seems to generally be considered "a lot." BT reports that as little as 3/8 turn will fix stalling issues at idle.

LolaMan reports that this has no effect on idle mixture, that is electronically controlled by the ECU's and the injector opening interval. This bypass screw just adjusts idle air bypass around the throttle plates. That's why it's important to do both sides/throttle-bodies equally, otherwise everything goes cattywompus...

FerrariOldMan says: To do this absolutely correct, you will need to block off the idle motors, not just disconnect them. Using the manometer hooked to both banks, you will open the bypass screws enough to set the idle to about 850 RPMs and watching that the banks are "balanced" i.e. drawing the same amount of air. To get it to idle this high without the idle motors active, you will need to turn the bypass screws out a lot. After this procedure is completed, you will need to reconnect the idle motors, then disconnect the battery for a short time, restart the car, and allow the ECU's to relearn their parameters (10 minutes of not touching the throttle, etc.).

To block off the idle motors, Vern Cornell used round rubber stops that you can buy at the hardware store and insert into the hose connected to the valve: "Remove the hose at the air cleaner side ie; inlet side to the valve and insert the stopper there. Don't unplug the connector that will turn on the CEL not that it will make any difference but there just no need to disconnect it."



My idle was surging and the car became impossible to drive safely. It would rev by itself up to 3-4K RPM and surge on its own even further above that.

Fearing the worst, I searched all the idle related topics in the past but spent all my time thinking it was related to the ECUs/Air Flow/Idle electronics since it occurred after an ECU reset.

Finally, I started checking the linkage itself because it seemed too stiff to me. Bottom line is it wasn't the electronics at all...the car simply had sat too long and the linkage got gunked up now that the weather has turned cold. The car's behaviour wouldn't make you think it was this simple because of the random surging.

Take a minute and lubricate the linkage horizontal shaft at both points (either side of the throttle cable) where it mounts underneath the intake plenum. Thanks, glpellegrino









One Fix For A Sticky Throttle (Thanks, Justyn)

Adjusting the 348 Throttle Linkage/Cable/Slack (thanks, Miltonian)

High RPMs at Startup? You may need to reset your ECU.

Other potential high RPM causes are:
1. floor mat is rubbing accelerator pedal (hey, don't laugh, it's happened to me)
2. throttle cable is sticking (needs grease or cleaning or there is an obstruction)
3. throttle linkage cross-bar (connects the bars that go to the tb's) joints need WD-40
4. mixture is too rich or too lean
5. idle air controllers are old or need cleaning
6. idle air passage-ways need cleaning
7. loose alternator belt is causing voltage fluctuations (Motronic 2.5 and 2.7 use the alt/batt voltage to determine the base fuel mixture)
8. obstruction in your exhaust


Low idle RPMs at startup?

1. You may have a Throttle Position Sensor (TPS) that is failing to tell your Idle Air Control Valve that your car is at idle RPMs.

 2. You may need to adjust your idle air bypass screws (see below).


348 Throttle Cable

What I thought was a snapped throttle cable on my 348 Spyder turned out to be "garage queen gunk." Actually, I drive the car frequently and I'm not worried about increasing the miles, but it has been winter in Atlanta and it has been parked for about 6/7 weeks.

I pulled the car out last weekend to warm and as I revved the engine to go into first gear, the engine revved high as if I had the gas pedal pressed to the floor (clutch was still half engaged). I immediately turned the car off and re-started with the same symptom. The gas pedal was limp with no tension whatsoever.

I opened the engine's deck lid to find the throttle cable loose and off it's guide cam. I was convinced that the cable was snapped and disassembled the housing just below the gas pedal to find that everything was intact. I went back to the engine and the linkage connected to the throttle cable was stiff and did not spring back. I inspected the coil springs on the throttle linkage to find no problems except they were oily/greasy. I sprayed both sides with WD-40 and started to work the linkage back and forth. Voila!! It sprung back and has operated like a charm since. A little WD-40 loosened the gunk around the springs. Thanks, Lumberman


Adjusting Idle Speed (2 methods)

Target Idle Speed: Ferrari shows the warm idle speed specification as 950 +/- 100 RPM (thanks, 91TR)

IDLE Adjustment, part 1: Connect a large U-tube mercury manometer (see picture above) to the intake plenum, one port on the 1-4 bank, one on the 5-8 (don't bother with vacuum gauges, doesn't work at all).

Disconnect the idle air speed motors electrical connector and block their ports into each plenum (see tips above).

Disconnect the Intake Compensation Solenoid Valve**.

Balance the airflow relative to each bank by adjusting the brass colored screw on each throttle body.

Do not touch the butterfly stop screws, the throttle bodies are factory set.

Monitor idle speed, should adjust to about 1000 rpm, adjust with airflow bleed, not butterfly.

Ensure that the exhaust is not blocked by a bad catalyst.

Measure exhaust gas content for additional clues.

Reset ECU's by disconnecting battery for about 10 seconds and allow them to "relearn".

Last car I could not flow balance at idle was a Challenge race car and turned out to require valve reseating. So, you could also try a leak down test to see what's up if the above does not work. * thanks rexrcr



Idle Adjustment, part 2:

A rough idle, exhaust burbling, exhaust popping on deceleration to idle, hesitation on acceleration from idle, and other problems are sometimes caused by the idle air bypass passages in the 348 throttle bodies (tb's) becoming clogged over time (this will happen on all 348's eventually).

When this is the cause of a problem, the solution is to clean the idle air passages.

To clean the idle air passages, first it's a good idea to check that the linkage is in sync on both tbs. When you first move the throttle cable, do both linkages move in both tb's at the exact same time?? Often, the lube has gone away in the sockets and there's some wear in one more than another. This will cause differences in the running of the banks and a little power loss. Remove the throttle linkage. Look carefully and you'll see the little clippie that retains the ball in the linkage socket. Either end first. DON"T LOSE THIS CIRCLIP.

Disconnect the throttle position sensors (tps) wires. You can probably leave them on the tb unless you've got some exterior cleaning you want to do. If you remove them, mark their exact position. If this gets messed up, it's an easy fix, so don't obsess about it.

Disconnect the air intake hoses. There will be grease and gunk in these, so it's a good time to clean them out. If you want to remove the screens from the air sensors, now's a good time to (sorry for this Ferrari heresy, guys).
Remove the four nuts (marked "tb bolt" in pics) from the tb. Wiggle it a little to free it from the gasket. There's no sealer on the gasket. Pull it off! If the gasket gets messed up, just go to the parts store and buy a sheet of bulk gasket material. Kinda thick stuff, but don't obsess over thickness, because all you're doing is sealing between two machined surfaces. Use the tb as a pattern and a razor to cut it out.

With the TB's now removed from the engine, loosen lock nut on idle bypass screw. Now screw the idle screw IN counting the exact number of turns (so that you'll know how to get it back to the right setting). Then unscrew and remove the idle bypass screws, clean out the idle air bypass passages, return bypass screws to original position by inserting and screwing them in all of the way in and then backing them out the right number of turns. Tighten the lock nut down and replace TB's on to the engine.

Cleaning can be done with any chemical you like to use to clean out grease or carbon. Just be sensitive to the fact that the outside finish of the tb is usually crinkle paint.

When you reassemble the tb's to the plenum, tighten the nuts well, but don't honk down on them. Again, all you're doing is making a seal between machined surfaces and there isn't a great deal of stresses against them.

If the linkage requires adjustment and lubrication-any grease will do-, you'll see how on the end farthest from the tb's, screwing in the threaded plugs in the ends. They should actuate at exactly the same time. You'll figure it out-not rocket science. Good luck and enjoy. Thanks, plugzit


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Engine & Underhood

How To Change 348 Fuel Pressure Regulators (to test an FPR, simply pull the vacuum hose off - the presence of fuel in the vacuum hose means that you have a bad FPR)

 Changing Your Ferrari 348 Fuel Filters

(Thanks, Miltonian and ShanB)

Remove the gas cap to eliminate any pressure in the tank and do it when the motor is cold. The filters are cleverly mounted above the exhaust so I dont want you to set the car on fire.

Replace all the copper seals on the fittings, wrap one round of special (yellow cannister, not the red cannister, not the blue cannister) gasoline-safe teflon plumbing tape around all of the the male threads, and be sure to install the filters with the arrow pointing in the direction of fuel flow (i.e. up).

When restarting have someone else start the car while you stand over the engine compartment and check for leaks. If you don't see any wipe all around each fitting with your clean finger and then smell your finger for the presence of gas. That is about the only way to find small leaks. You must have absolutely zero leakage. Thanks, RifleDriver

Air Intake Whine / Noise / Squeal / Whistle / High Pitch The 348 does something unique from 3500 to 5500 rpms; we've got Intake Compensation Solenoid Valves. The ICSV is activated between 3,500 and 5,500 RPM's. This improves torque by opening our Compensation Throttles (helmholtz resonators). And it can be a mysterious, hard-to-diagnose source of noise if the ICSV is bad, or if the ICSV tubing is too old to seal air, or if the vacuum tubing involved has a leak.

Changing Your 348 Phase Sensor On Rear of Right Intake Cam (under airbox)

1) Disconnect the battery
2) Remove the air box, for more work room
3) Unplug the sensor from the wiring loom (push down on the exposed metal wire on the black plastic electrical connector and simultaneously pull)
4) Remove the three 5/16" nuts holding the housing to the back of the head
5) Remove the 5/16" nut holding the sensor-cable/bracket to the left side of the cover
6) Pull the housing cover toward you away from the engine/cam

7) Use a flat-blade screwdriver to unscrew the 3 screws that hold the large metal half-circle to the cam, and then gently pull the half-circle off and install your new half-circle (avoids long-term magnetism issues).

ONLY IF OIL LEAKING IS DETECTED INSIDE YOUR COVER THEN: 8) Using a large socket, insert it through the front of the housing and knock out the rear cam seal. Be sure to pay attention to which way the seal is facing before you remove it, that way you can put the new one back in the correct way.

9) Use a 2.5mm allen wrench to unbolt the two bolts that hold the phase sensor to the cover that you removed in step 6, and remove the phase sensor from its Step 6 cover.

10) Install your new phase sensor into the Step 6 cover and tighten the two 2.5mm bolts.

11) Place your cover onto the 3 posts on your cam/engine and tighten its three 5/16" nuts.

12) Install your Step 5 bracket onto its interior-side cam post and tighten its 5/16" nut.

13) re-connect your black electrical cable to your phase sensor plug

That's it, no big deal. You can have the thing/s changed in about 30 minutes. Just be careful when you are putting the housing back on so that you don't goof and fold the lip of the new seal (if needed in Step 8). Thanks, ernie and No Doubt




Crank Sensors / Engine Misfires or Misses

Our 348's have two crank sensors. These components are located above the front drain for the engine oil. These crank sensors *do* go bad's more common that one of the AMP wires/pins in the black data cable connectors to them has come undone. Peel back the black rubber boot on each data cable to check the wiring.

Bad crank sensors/wiring can cause ECU errors, engine misses, engine misfires, fuel pumps to not run (a safety mechanism for crashes), etc.

AMP Connectors for Crank Sensor Wiring (thanks, DaveHanda)

Our tachometer receives its signal from the 5-8 ECU, which gets its signal from the 5-8 crank sensor (AKA "rpm sensor") that is mounted just above the forward-most, front-side-mounted engine oil drain. Both crank sensors are identified as #41 in the diagram below.

If you need the actual rpm sensor: has our crank sensors (Ferrari 348 part #130975) for $119 (volvo part# 1367645).

This site lists that Volvo part (1367645-7) and the Bosch part (0 261 210 029 ) as the same thing:

Our 348 crank sensors are also Fiat part # 7616269 and Kia # 0K2A6-18-891


Main Rear Engine Seal

pics thanks to Jack Russell Racing


Seals #1 & 2 go in facing the engine. Seal number #3 faces the tranny. If you look at the seal you will see that it is sort of cupped. The side with seals #1 & 2 would be the top of the cup, and #3 the bottom of the cup. Like in the bottom picture with the seal lying flat. You want the two seals, the side facing up in the bottom picture, facing towards the engine to keep the oil in the block. That way you will have both of them working against the pressure build up in side the engine block. When you have it in, the back of the seal, the side facing the gear box, will be nice a flush with the back of the engine cover.

There is a little trick I used when I put mine on. As you know the seals are a bit hard. You need to get them to spread open a bit in order to get it over the back of the crank. You can't just push it on. You have to have the seals spread open in the dirrection they are facing, otherwise it will leak. So to get them to open here is what you do.

Get a long funnel, like the kind you would use for automatic transmission fluid. Place the funnel facing down, with the tip up. Now take the seal and gently push it down onto the funnel until the seals have spread just enough get over the back of the crank. You don't want to open them up too much, you still want it to fit snug. The back of the crank has a little rim running around it that will help you get the seal over. So you want to open it up so the seal almost gets over the back of the crank, but not quite, yet does fit over the little rim. You'll see what I'm talking about when you take the old one off. The other thing is that I pressed the seal on the back of the block cover first, opened the seals via the funnel, then pushed it on the back of the crank. While you are at it you may as well replace the seal that runs around the inside of the cover.

Oh yeah another thing. Before you press the new seal into the cover you will want to put a little bit of high temp silicone sealant inside the bottom part of the cover, where the seal gets pressed in. Make sure you get it to go all the way around the bottom inside rim. Don't go over board with it though. All you need is just engough to make a nice seal between the cover and the cup of the seal. I don't know why these guys designed the side of the seal housing the way that they did but, how in the heck do they expect metal to seal with metal??????? There is nothing to seal the outside of the cup. So you may have it nice and snug over the crank, but it will still leak around the outside of the cup, in between the cover, because there isn't anything to keep the oil out. Anyway put some hi-temp silicone seal in there to keep it from leaking around the outside. I used Hondabond HT. I also put the Hondabond around the groove for the cover seal before I put the new cover seal in. Pressed everything on nice and careful, and no leaks to date, not one drop.

Happy wrenching. Thanks,




Normally, a hot 348 after a drive will push pressurized fuel vapors OUT of your fuel fill line when you remove the fuel cap at a gas station. If you notice the opposite behavior, air rushing IN, then read this:

Ernie’s step by step pictorial for removing the 348 fuel tank:

Changing your Ferrari 348 Fuel Tank

Do not have the 348 put on a drive-on lift; the tank is so wide that it won't clear the ramps.

thanks, Walclare
0) Remove the gas cap to relieve pressure
1) Jack up the car and remove the rock shield
2) Drain the tank
3) Disconnect the shift linkage
4) Disconnect the electrical connection on the fuel pumps, and disconnect the fuel lines
5) Disconnect the evaporation tubes
6) Remove the front part of the left rear wheel well liner, then you'll have access to disconnect the filler and over flow tubes
7) Double check that everything is disconnected
8) Support the bottom of the tank with two jacks, then remove the two support brackets
9) Lower the tank out.

I haven't had to remove the tank, but I'm pretty sure the removal would go something close to that.

Thanks, ernie

Hose Tip: whenever you have a rubber hose that has welded itself to a metal part, e.g. a radiator hose to radiator or fuel hose to fuel line, you can take something pointy such as a screw driver or scratch awl and try to slide it between the hose and the metal part. Now spray wd 40 between the inside of the hose and the metal part. Then you work the screw driver , scratch awl around the inside of the hose/outside of the metal nipple to unstick the hose. The wd40 really helps loosen things up. Anytime you have rubber touching metal, wd 40 is of great help in getting stuff apart and putting it together. *thanks, osuav8r



A/F Mixture

Your two Ferrari 348 MAF's are factory set initially at 383 Ohms resistance each. You can adjust their resistance (this resistance can be measured with the engine off by connecting an Ohm-meter to the outermost metal pins, number 1 and number 6, beneath the data signal cable on each MAF) to or from this value via a screw beneath the disposable blue cap on each MAF sensor. Adjusting the MAF resistance value will change your Air/Fuel mixture setting.

Turning this MAF screw clockwise with a flat-blade screwdriver (see photo below) thickens your air to fuel mixture ratio (per the factory workshop manual, anyway), i.e. leaning. Turning this screw clockwise will also **INCREASE** the resistance value that is measured between the outermost pins (i.e. pins #1 and #6).

Conversely, turning the mixture screw counter-clockwise should thicken your fuel to air, i.e. enriching. Turning this screw counter-clockwise will also **DECREASE** the resistance value that is measured between the outermost pins (i.e. pins #1 and #6). The lower the resistance the richer the mixture. Thanks, group77racing

If your mixture is too rich or too lean, then your ECU's will set off one or more trouble codes. Too rich (i.e. too much fuel) and your catalytic converters will run too hot (they can glow dimly red at night - FIRE DANGER). Too lean (i.e. too much air) and it will take long periods of cranking time before your engine first starts when cold, doubly-so for starting when hot. As a general rule of thumb, both MAF's should have identical resistance values, regardless of your preferred resistance value setting (typically close to the factory pre-set 383 Ohms).

In the above MAF photo, the screwdriver is touching the Air/Fuel mixture screw (AKA the "CO" screw). To the immediate right of the screwdriver is the data cable for the MAF. On top of the MAF data cable is a barely visible, thin, spring-loaded wire that is running perpendicular to the screwdriver. Simply press down on this wire to unlock the MAF data cable (useful when disconnecting the MAF data cable).

These MAF's are self-cleaning. The internal MAF sensor wire is heated to a very high degree setting a few seconds after you shut off your 348's engine (if you've driven it long enough to first get up to operating temperatures).

Inexpensive (about $190) Ferrari 348 MAF rebuilds are available here: also has a guy rebuilding Bosch parts for around $100 per MAF (and they rebuild ECU's).

New Ferrari 348 MAF For ~~ $330

The Ferrari 348 MAF part # from Bosch is: 0 280 212 018. This part is also used on some early 1990's series Saab 900 and 9000 non-turbo vehicles. The Saab MAF's (0 280 212 017 and 0 280 212 018) are set to a widely different resistance value, so you will have to reset this value by the above mixture adjustment process for your 348.

 Return To Index

Clutch and Transmission/Flywheel

Changing 348 Transmission/Tranny/Gearbox Fluid (thanks, Daniel, resnow, Miltonian)

To perform the job properly, here's what you'll need:

1. Five liters of your favorite gear oil (though you'll only use 4.2 or so), such as Redline's "SuperLight Shockproof" ** (it's yellow, helps your 2nd gear shifts when cold, and the color tells you instantly if you are leaking tranny fluid instead of brake/engine-oil/flywheel grease or if you or a mechanic might be draining the wrong fluid) or Redline's "75w90NS" or Amsoil's 75w-90 Severe gear oil

**If you are seeing condensation in your gear oil then you may want to use Red Line's special "75W90NS" instead of "Superlight shockproof" to prevent corrosion.

If you are noticing grinding or chattering then the "75W90NS" may also work better. In contrast, the regular Red Line "70W90" (a different product than "75W90NS") and "Superlight shock proof" have antislip additives that may not stick to gears as well.

Redline does make a slip additive that can be added with "75W90NS." - Thanks,

Redline’s Lightweight Shockproof gear oil (it’s blue) seems to shift as well as Redline’s SuperLight Shockproof, and offers more gear/bearing protection.


2. A fresh crush washer 10263460 for the magnetic drain plug

3. A fresh magnetized gearbox drain plug, 104280 (optional)

4. A 10mm hex wrench for opening/closing the bottom drain plug

Thanks, Pap 348
5. A 19mm (.75 inch) mambo-sized male hex wrench or 5/8 inch spark plug socket plus extension for the main fill hole plug on top (under your stock air box - labeled "C" above)

6. A 17mm female socket wrench for opening your tranny dipstick (labeled "A" in the black and white sketch above) and few assorted slotted and Phillips screwdrivers for removing the air box

7. A container to catch all the oil and a crappy car or pickup truck to transport it to a proper disposal site.

8. A nice long funnel for refilling the gear oil. Note, in case of emergency (say, you drain the gear oil but can't manage to remove the top fill plug, you *can* fill the 348 transmission via the tranny dip stick's just slow -- thanks Spider348).

* Might be a good idea at this point to remind the brothers to put a dab of anti-sieze compound onto the threads of the transmission dipstick (and main fill plug) while it is out. Those things have a reputation of being really hard to break loose sometimes. Thanks, Miltonian


 Additional Tips/Tricks Are In This 348 Gear Oil Change Thread Thanks, Pap 348


Fixing Clunky Shifts

You *can* speedshift the 348 box, but you've got to do a few non-stock things first.

Drain the old gear oil when hot, fill with automatic tranny fluid, rotate wheels in air with tranny in 5th, then drain out the auto fluid and fill with Red Line's Superlight Shockproof.

2. Lube the stick shift tower itself where it hits the metal gate, and lube the 2 levels of mechanicals below the gate with white lithium grease.

3. Install a slickshift gate or dremell down your stock gate so that your stick tower makes no 90 degree turns while changing gears.

4. When you start your 348 the first time in the morning, hold down the clutch pedal, shift into 1st gear, then press down the stick and smoothly shift into Reverse and let out the pedal to back out of your garage. Next, make your first forward motion shift be 2nd gear instead of 1st gear. This just matters for your very first motion forward. The rest of your driving day will be fine after this "reset" of your tranny.

5. Speedshift into gear only as your RPMs are **INCREASING**.



All about 348's and "355 Challenge" Flywheels -Fixes/Sources/Cooling/Issues (click here)


Transmission Shift Shaft Seal Leak

 (picture thanks to ecoloqua)

A sudden, pungent smelling puddle of fluid (see above) may be from a transmission shift shaft seal leak in your 348, F355, early TR, or Mondial T.

You can get to that 348 seal (part #55 below) easily. Easy to replace the seal, too. It's underneath the car on the transmission, right behind where the shift linkage is attached to the selector/slider. You don't even need to fool with the shift cables on the slider. The slider is held on with only ONE allen screw. Undo this one screw then move the cockpit gear shift lever into 3rd gear, and presto the slider is out of the way, with the cables still attached, and you now have access to the seal. Remove the old seal and insert the new one (a $2 part new from Ferrari - #146306). I can get to that seal in MINUTES. Thanks, ernie

I couldn't get into reverse or 2nd (86 TR). Turns out there is a rubber bushing on the shifter rod (see above) that was oil soaked, that prevented full shift rod travel. - Jeff Pintler




Transmission fluid from the drain plug (see below) means be smarter than No Doubt (that's me) by remembering to use a fresh crush washer when you tighten up your tranny drain plug (e.g. after a fluid change). That's the $0.85 fix. The flywheel grease fix is a bit more. See also: Flywheel Grease Fix *thanks, No Doubt


FlyWheel Grease Leak (or transmission fluid leak)

Fluid from the ventilated inspection cover of a 348 (see above) often means that some component (e.g. a seal, a bearing, a clutch/brake cylinder, etc.) has failed, causing clutch/brake fluid to directly leak out...or for it to cause the flywheel grease to leak out.

Fluid leakage from the perforated panel isn't terribly serious, at least it's not as bad as an engine rear main seal or something like that. Potential causes include leaking "triple seals", or leaking clutch slave cylinders, or flywheel problems. It only takes about an hour to remove the clutch housing from the back of the drive train for diagnosis of the problem. I would recommend that you carefully check the level of the brake fluid in the reservoir in the front trunk according to the description in the 348 Owner's Manual. The fluid in this tank also operates the hydraulic clutch, and if the level gets low enough (due to a possible leaking slave cylinder) then you will have trouble disengaging the clutch when you press the pedal. It's easy to check. *thanks, Miltonian

Clutch Fluid Leak: An overfilled brake/clutch reservoir will drain in the center of the car near the front bumper.

 348 Flywheel Assembly Pictorial (thanks, ernie )




AP Racing sells the 348 Clutch

Single-Disk 348 Clutch

Borg & Beck part # OCL3403000 clutches also fit (thanks ronr)

If you're doing any clutch work, here are some super-high quality items you may want to consider:
136879. Flywheel bolt for 348.
168156. Flywheel bolt for 355.



How To Change the Clutch on a Ferrari 348 (twin clutch model) using the Ferrari OEM clutch replacement kit. The instructions are provided at your own risk.

Clutch Replacement Pictorial

Step 1: Jack the car up. Step 2: Remove the muffler.

Step 3: Remove the cover nuts from the clutch housing. Step 4: Press clutch pedal to release the cover and clutch assembly from the pilot bearing.

Step 5: Remove the clutch pack nuts. Step 6: Remove the slave body.

Step 7: To install the new clutch, position the clutch pack and use the two long bolts from the starter/clutch cover to help compress the clutch pack. Place these bolts 180 degrees apart. Before you tighten, use the clutch alignment tool to align the plates to the pilot bearing. Make sure that if you're using a smooth tool that you line-up the splines of the two plates together. Eyeballing it works fine. A splined tool is not required. As the clutch pack is compressed, start the clutch pack bolts as they meet the threads then replace the starter bolts with the correct final two clutch pack bolts and torque to 20 ft-lbs.

Step 8: Place the throwout bearing/slavebody combination back on the slavebody flange shaft.

Step 9: Bleed the slave body by bleeding the clutch in the same manner as a "two man" brake bleed. Have one person open the bleed screw as the other person pushes the slavebody toward the transmission until it stops, then close the bleed screw.

Step 10: Push the clutch once again to get the slavebody to move away from the transmission then Step 9. Repeat Steps 9 & 10 until all the air is gone.

Note: You cannot simply replace the throwout bearing because it is part of the slave body. Early 348s may still have the non-updated throwout bearing/slavebody combination which can be disassembled, but parts are unavailable for them. You can have the bearing rebuilt by some bearing rebuilders. The seals of the old slavebodies may be the same size as in the new updated part. The new part comes as a kit with one seal. You need to also get the other slavebody seal and two plugs for the flange so you can place this new flange in the car. This is a typical Ferrari kit with half the required parts!

Step 11: Place the clutch cover on to the tip of the pilot bearing/transmission shaft. As the cover goes on, rotate the free rotating clutch assembly until it indexes on the small splined input shaft. Use a large rubber mallet on the cover to drive the cover on, and as this is being done turn the wheels of the car to make the large splined clutch shaft rotate so as to index with the clutch plates on the clutch assembly. Drive the rest of the cover into place. This may be somewhat difficult as it needs to interference fit over the pilot bearing. A tip is to drive the cover into place enough so the longer starter motor bolts can be threaded until just hand tight to the cover, then rubber mallet the opposite side of the cover, then tighten the bolt a bit more, then rubber mallet again until the cover is flush with the transmission case.

Step 12: Place the cover nuts and tighten. Step 13: Replace the muffler.

Step 14: Lower the car and test. (Thanks Dr. Carl!)

348 Clutch Part 2

EXTEND CLUTCH LIFE, FOR FREE! 348 clutches are shipped from the factory when new with clutch pack shims. Presuming no undue wear or damage to the clutch/pressure plate/fingers/flywheel/bearings/seals during the average duty cycle, 348 clutch life can later be extended after normal usage by simply removing these (or using shorter) clutch pack shims. Thanks, FerrariFixer

How To Change Your F355's Clutch (thanks rf128706)


348 clutch "throw out" bearing (AKA clutch release bearing, AKA clutch "thrust" bearing, AKA clutch slave cylinder) picture thanks to ShanB

Clutch Slave/thrust/release/throw-out bearing replacement pictorial

348 Clutch Slave Cylinder/Release Bearing (Thanks Fana355France)

Is your clutch slipping? My clutch plates were worn to the rivets - way past spec, so my clutch was slipping when I applied full power in any of the high gears. Well, the pressure required to operate this sort of diaphragm spring increases as the clutch plates naturally wear. Ferrari did not leave a great deal of overload tolerance on the slave cylinder throw-out bearing unit so it went pop.
Lesson: Dont ignore a slipping clutch even if it's only a tiny bit.

I have read of people having problems bleeding the clutch [after replacing the slave]. The following worked with no problems for me. I was on my own and hadn't got a pressure bleeder to hand. The system was empty so I filled it before fitting the slave. After a few minutes fluid starts to leak from the hole in the flange. Open the bleed. Push the slave on as far as it will go and fit the guide. After a minute or so fluid starts to leak from the bleed. Close the bleed and pull the slave out as far as it will go. Wait a minute or 2. Open the bleed and push the slave as far as it will go. Air bubbles out of the bleed. Do this a few times until no air comes out of the bleed.
Reassemble clutch and refit pumpkin. Most of the air is now out of the system. Loosen the bleed ever so slightly and put a clear pipe on and into a bottle of fluid. Pump the pedal a few times. If the bleed is just cracked open you will feel air going out through the bleed. Keep the reservoir topped up. When there is no air. Tighten the bleed. Mine took about 5 or 6 pumps of the pedal. No Jacking up. No spongy pedal. If anything there is less drag and gears are easier than before it went bang.

Job done. Easy.

Thanks, 348Pilot


Remove and Replace Clutch Slave + Triple Seals (thanks, Stevew)

Is your clutch throw out (thrust) bearing (this part is mated to the 348's clutch slave cylinder) going bad? The symptom of a bad t/o bearing on the 348 is a very loud sound like a slipping dynamo belt . This noise occurs either when pushing in on or releasing the clutch pedal. The noise is so loud that you need to put fingers in your ears.

Another sign of Clutch Slave Cylinder/throw out bearing failure is a puddle of clutch fluid and no ability to shift (clutch pedal goes to floor). Blue seals inside old clutch slaves can be replaced, but black seals can not always be replaced.

When removing: pay attention to seal direction/alignment; match new seals similarly.

OEM #155226 CLUTCH RELEASE (throw out) BEARING for 1993 THRU 95 348TB/S (SKF # BB1B631107) - also #177784 (shared with 355), #168594 (for twin discs), and # 176560 (for twin discs). 176560 was updated/replaced with bearing #168594.

There were at least 4 different Clutch Release (throw-out or "thrust") bearings used by Ferrari over the years on 348's. It's quite possible that any of the 4 will work for your year model 348.

*Some late model 348's shared throw out bearing/thrust bearing/slave cylinder units with the 6 speed manual 355's. Hill Engineering has a reasonably-priced, superior replacement unit for sale.

New clutch release bearings are sold without seals. You'll need to purchase: Seal #176561 OEM £8.50, Seal #176562 OEM £14.90, Seal #176563 OEM £21.30, and Seal #172499 OEM £1.90.

Can't Get Your 348 Slave/Release Bearing Re-Installed?

Lube seals with brake fluid but make sure you have the seal direction correct first (it will stick when going back on the shaft if a seal is in backward). Very carefully make sure your seal is 90 degrees to the shaft. The fit is not unlike a bearing on a shaft. Then smack it quick with a rubber mallet and it should go right down. Thanks, fatbillybob

Triple Seals

There are actually 4 seals, 3 together (left of screwdriver, below) and then one slightly larger snap ring / O Ring to the right of the screwdriver in the picture below. These are referred to colloquially as the infamous "triple seals" and should be replaced whenever changing clutches or slave cylinder (soak them in boiling water to heat up in order to get them to gently slide onto the shaft without tearing - temporarily wrap some paper around the shaft to avoid the seals dropping into the wrong gap and go smoothly over the splines).

You can put the seals onto a piece of wrapped cardboard, then slide the cardboard tube down the shaft, then slide the seal from the cardboard tube onto the shaft.
These seals can be purchased at lower prices from non-Ferrari sources as they are 3rd party seals.

pic thanks to need4speed348


While you're there, replace the "4th" O-Ring on the Clutch Shaft. Ferrari part # 104984

 thanks, kingsdare


Clutch Pedal Adjustment 

To adjust the clutch pedal "free play"-
Loosen lock nut on pedal alignment pin 4, then screw in the threaded pin to make slight contact with the clutch pedal in the rest position. Then screw in 1 more full turn. Tighten lock nut. This will take up any "slack" in the clutch pedal.

To adjust the clutch pedal "travel"-

Loosen locknut on rear pedal alignment pin 6. Screw out the threaded pin 3 turns. Press clutch pedal down exactly 126mm, then screw alignment pin in till it makes slight contact with the clutch pedal. Then screw in 1 more full turn. Tighten lock nut. Both clutch pedal stops are set. Recheck to make sure you have 126mm clutch pedal travel.

If you dont have 126mm pedal travel, then do it again to make sure you get it right. Thanks, Pap 348!



Part numbers in pic-
1-Clutch master cylinder pushrod.
2-Adjustment nut.
3-Pedal return spring.
4-Pedal alignment pin.
5-Clutch pedal.
6-Pedal travel adjustment pin.











You have to bleed your clutch lines very, very thoroughly after installing a new clutch release/slave bearing, otherwise you won't be able to get your 348 into gear when the engine is running.

After traveling from the clutch master cylinder towards the rear of the engine bay, the clutch line Tees off. One line runs vertically and then into the clutch housing, the other line runs out towards the bleed valve.

So, to bleed the clutch, one needs to be displacing fluid into the clutch slave cylinder. The only way I know how to do this is to depress the clutch pedal (several times) between each individual bleed operation. By depressing the clutch pedal, one moves the clutch (N.E. brake) fluid up this tube and into the slave.

Don't be surprised if this takes a considerable amount of tries before the clutch is working normally. Eventually, you will have pushed enough fluid into the slave and the air will be expelled. *thanks,
mitch alsup


 348 Clutch Sticking

348 Clutch design problem: It is becoming increasingly common to see 348's with broken diaphragm spring fingers. This prompted me to look further into it. I use a consultant engineer to rebuild my clutches, and between us, it hasn't taken long to work out why. The clutch diaphragm is being overthrown, due to either excessive pedal stroke, and/or oversize clutch master cylinder and/or undersized clutch slave cylinder.

Further to this, your clutch diaphragm is actually more prone to breaking if you have had "precautionary" clutch changes... often sold by dealers as a "while the belts are being done....etc"

The reason here, is that with a new clutch fitted, the diaphragm is already flexed a fair way (the fingers are flatter) before you even press the pedal, so operating a "new" clutch, overthrows the diaphragm even further than once it's worn a bit and the fingers have raised a little. This constant overthrowing gradually fatigues the diaphragm spring, until after X amount of operations and heat cycles, it begins to fail. City driving is a killer in so many ways.

The solution..... either fit a pedal stop to reduce travel, or replace the master cylinder for a smaller bore size. A smaller bore M/Cyl is the best option, as it also gives better feel and graduation during take up. *Thanks, FerrariFixer


Upgrading to the F355's 6 Speed Transmission (Thanks to Andy Hls)


A Common 348 Transmission point of failure: a common 348 racing failure (also in a 355) that another mechanic and I believe we found out why:
With a new drop gear and shaft the "fit" on the splines is tight enough that a great deal of pressure is required to fully seat the gear against the shoulder. We found evidence that at least occasionally the guys in the gear box department were getting lazy and not fully pressing on the gear...and instead were relying on the nut alone to fully seat it. Wrong! The nut will come to torque slightly before the gear is fully down so there is no clamping pressure that way. Only the size and strength of the splines keep them running as long as many of them do. Once the splines start getting a little worn and the gear starts working back and forth the nut often follows, catastrophically. If proper attention is paid at clutch replacement time it is often found and fixed before very serious damage is done, but even just replacing the input shaft and gear alone is $$$$$. Have seen this scenario many times. *thanks, RifleDriver
348 Transmission Blow Ups

348 Transmission Rebuild Secret = Lapping (re: glazed synchros impacting gear shifts): I've seen that glazing quite a bit on the iron Ferrari syncros. Most of the time when I get into a TR or 512 box for syncro problems the syncros actually have little wear but the surface is cooked looking like an overheated flywheel. It is from using an improper oil (like the Agip garbage they used to have us use) and forcing the shift much like when you hear of people complain when those boxes are cold and balky. If you force shifts in that situation that is what will happen.

Lapping the synchro surface with valve lapping compound works quite well in restoring the syncro ring. I lap all syncros new or glazed to make them fit the taper better, makes them shift great.

When you lap no break in required, Shifts great leaving the driveway the first time.

Compound between the ID of the syncro and the OD of the gear taper.

The iron syncros in Ferraris are pretty hard so I would assume you are removing some material from both but no more or less than during the break in period of the syncro.

It gets rid of a lot of the balkiness. If you have ever noticed the iron syncro boxes take many miles to really break in. I have seen TR boxes take 20k miles before they shift smooth. Lapping makes that quality of shifting happen today.

I start with a coarse valve compound and finish with a fine and just look for a consistent pattern the same as you would on a valve.

The square area on a syncro as compared to the square area on a valve is so large you have to start with a coarse grit to keep the job from turning into a career. Also wrap the syncro with a rag so the dog teeth won't rip the skin on your palm to shreds. Thanks,


The Warning Whine Sound From 348's and Mondial T's Prior To Catastrophic Transmission Damage

Using Red Line's "Superlight Shock Proof Gear Oil"; it is a yellow-colored liquid) in your 348 transmission and differential will lower your motor's oil temperature during casual driving (as well as make your shifts between 1st and 2nd gear silky smooth even when the engine is still cold). Red Line's "75W90NS" will also work to improve shifts, and it attracts less condensation than the yellow Superlight shockproof gear oil...but don't confuse the good "75W90NS" with the older "75W90" gear oil that will NOT improve your shifts. That "NS" is important.


348 Transmission Removal

Here are the steps to remove the transmission from a 348.
1) Disconnect the battery.
2) Remove the air box for more work room.
3) Block the front wheels and then jack up the rear of the car. Now place jackstands under the subframe for safety (348 Jack Points).
4) Remove the rear wheels, and then remove the rear wheel well liners.
5) Disconnect the cables on the starter.
6) Disconnect the ground strap from either the transmission case or the clutch housing.
7) Undo the connection for the speedometer sensor.
8) Disconnect the connection on the top of the transmission for the clutch/brake fluid.

9) Drain the oil out of the transmission (see pictorial above).
10) Drain the engine oil. Then disconnect the oil line from the engine block. Remove the brackets holding the oil line to the side of the transmission, and move the oil line out of the way.

11) Remove the rear bumper for better access to the muffler, and clutch housing. This step isn't totally nessesary, but it does give you much more room to work with.
12) Remove the muffler/s.
13) Disconnect the inner CV joints from the transmission (348 & 355 CV joint to tranny flange torque=57 ft/lbs)

14) Disconnect the parking brake cable (348 Hand Brake Adjustments).

15) Remove the cover for the shift linkage and then disconnect it from the transmission.

16) Remove the two cross beams on the bottom of the subframe, running under the transmission.

17) Remove the sway bar

18) Roll a floor jack under the transmission, and center the lifting point of the floorjack under the bottom inspection plate for the transmission. You can place a block of wood on top of the jack so that you don't dent the inspection plate. Now lightly support the weight of the trasmission on the floor jack.
Thanks, Pap 348

19) Loosen the 8 large nuts holding the transmission to the back of the engine block, but DO NOT remove them yet. There are 4 on the top and the 4 on the bottom.

20) Remove the 8 nuts holding the clutch housing to the back of the transmission and then remove your clutch .
21) Grab hold of the output shaft and pull the shaft to extend it. This is to disconnect it from the engine crank to give you the "wiggle room" needed to slide/pry the tranny away from the engine. You can't completely remove the shaft in this direction because of a bump in the shaft. All that you can do is extend it out far enough that the triple seals are exposed. That will disengage it from the back of the crank.

If you desire to remove it entirely, then first remove the shaft retaining clip so that you can push the shaft the long way through the whole tranny (after the tranny is out).
22) Completely remove the eight bolts holding the transmission to the engine block, and then move the O2 sensor wiring connection bracket out of the way.
23) Loosen the large bolt holding the top of the transmission to the crossbeam on the subframe.

24) Double check to make sure that everything has been disconnected properly, and make sure that the transmission is supported by the floorjack.
25) Remove the bolt holding the top of the transmission to the subframe.
26) Slide the transmission back, away from the engine, and off of the retaining bolts. It may be a little bit tough to get it to separate from the back of the engine block as there is a seal that must be broken. But it will come off. The seal is just a big o-ring that goes around the opening for the back of the crank.

27) Now carefully lower the transmission and roll it out from under the car.

pics thanks to Bmyth and FatBillyBob
Happy wrenching. (thanks, Ernie!)

 pics above by 1spdemon

The new rear main seal Ferrari part #183581:

rear crank seal installed

thanks, ferrarioldman and rifledriver


How To Bleed The 348 Clutch (fluid):

Fill your Motive Power Bleeder with some amount of DOT 4 brake fluid. Top off your Master brake/clutch fill reservoir with DOT 4 brake fluid to the fill line. Install your Motive Power Bleeder onto your Master brake/clutch fill reservoir. Pump your Motive Power Bleeder up to 10 PSI. Open your Clutch bleed nipple.

If your pumpkin is off, and if you have just changed your slave bearing, then manually push your new slave bearing in, then out a few times. Note fluid coming out of your clutch bleed nipple. Install your clutch pumpkin before continuing.*

Slowly press your clutch pedal to the floor and then release it. Close your clutch bleed nipple. Slowly press your clutch pedal to the floor again, noting any pressure/feedback on your foot, and then release it. Repeat until you have "normal" clutch pedal feel to your left foot.

Open the Motive Power Bleeder to allow it to depressurize, then remove it from your brake/clutch master reservoir. Replace the cap back onto your Master brake/clutch fill reservoir.


*You must bleed via the clutch pedal itself only with the clutch pack (pumpkin assembly) installed. If you try to bleed it with the clutch pack removed you will damage the slave/bearing assembly and snap the roll pin.

 Bleeding the clutch can fix some transmission grinding problems as well as solve some hard-shifting issues.


Other hard to shift issues (e.g. difficult 1st gear) can sometimes be solved by...

...Adjusting the shift cables:

Here is how you adjust them. Just below the shifter there is an armor cover plate which you will need to remove. This will require you to get the car up off the ground so you can get underneath. Once the plate is off you will be able to see the shifter linkage. It is just two cables that are threaded at the end with a thing that looks like a turnbuckle. As the car is driven these turnbuckle things get loose and the cable stretches/slips and becomes slack. All you have to do is put the shifter in neutral (best to hold it in Neutral with vise grips) and take out the slack by tightening the turnbuckles. While you are there grease the whole thing real good and do the same to the translator at the other end of the cables. If that is why you have a shifting problem then you will see a dramatic improvement in the way the car shifts. Mine use to be almost impossible to get into 1st gear but now it shifts like a dream. Thanks, airbarton


Ernie's Shift-cable Adjustment Method:

There are two places that you can adjust the shift linkage. The first and most common is under the engine, right were the linkage connects to the selector. The second place you can adjust it is under the bottom of the car, where the shift box is located inside the cabin. You can adjust the linkage at either location, or at both.

What you are looking to do is, make sure that the gear fully engages when you shift. You are also making sure that the stick shift goes fully into the slot in the shift gate, in ALL the slots. It is possible to have one or both of the cables either adjusted too short, meaning that the stick will be fully in the slot in the shift gate but it will not have fully engaged the gear. It is also possible to have one or both of the cables adjusted too long, meaning that the gear will be fully engage but the stick shift will not be fully in the slot in the shift gate.

Okay so here is what you do:
1) Make sure that the gear box is out of gear, and in neutral.
2) Block the front wheels so that they don't roll when you lift the car.
3) Position the floor jack under the rear of the engine subframe and lift up the rear, so that you have plenty of room to get under the car. Then you will need to place jackstands under the subframe for safety.

4) Remove the cover under the gear box where the cables connect to the linkage. You will now see the adjusters, on the shift cables, attached to the selector. The picture above is of what the adjusters look like. It is from under the shift box, but the adjuster looks the same under the engine.

5) Remove the nut and bolt holding ONE shift cable to the selector. You want to adjust ONE at a time.

6) Loosen the nut behind the adjuster, but DO NOT turn the adjuster yet.

7) This step is IMPORTANT. Remember to COUNT how many HALF turns you make in either direction. This is so that if you make the shifting worse you can put it back to where it was when you started.

8) To adjust the cable out, or make it longer, you turn the adjuster counter clock wise. Two adjust it in, or make it shorter, turn the adjuster clock wise. What ever way you adjust it, in or out, only make HALF a turn, and remember to COUNT the HALF TURNS.

9) After you have made your adjustment, attach the cable to the selector again, then drop the bolt through the hole from the top. You don't need to put the nut on yet, until the cable is adjusted to where you want it. This saves some time, because you could be taking the bolt out several times, and who wants to keep unscrewing a nut over and over.

10) Go inside the cabin and shift the gears to see if your adjustment made it better or worse.

11) Repeat steps 5-10 as needed, until you have the cable/s adjusted just right. This is where LOTS of patience comes in.

12) After you have adjusted the cable/s to where you like them, bolt everything back down.

If you are having a problem with 1st gear not going all the way in, I suggest you try adjusting the cable on the left hand side first. That is the left hand side of the car, looking at the car from the rear. Try making a half turn out, this will make the cable longer, and see what that does. It's going to be ALOT of trial and error, so be patient. Again remember to COUNT the half turns, and only adjust HALF a turn at a time. If you make thing worse you can put it back to where it was. Happy wrenching. Thanks, ernie.


Ferrari 348 Gearshift (stick) Lever Fix (thanks to need4speed348 and ernie)

You should wipe a little light lubricating oil/grease around the inside perimeter of the 348 shift gate plate as well as on the outside of the stick/lever/gearshift itself in the area where stick meets gate occasionally -- because wiping off all of the oil via shifting or by cleaning with a glass "Windex" type product (e.g. to shine the chrome) aggravates the wear of the gearshift, which can break and require replacement (see above hyperlinked thread by need4speed348 & ernie). The top of the shift gate can be oil-free (that's OK), but the inside edges shouldn't be oil-free. Thanks, 91tr



 *Ferrari gearshift after 34,000 miles of no oil/grease on gearshift or gate. You should proactively smear grease onto your gearshift in the areas where you see wear in this photo, as well as on the shift gate itself where your gearshift makes contact with your chrome gate.





The secret to the 348 gear shift (i.e. smooth shifts), in addition to using red line's gear oil, is originally shifting the car into 1st gear and while still holding the clutch down shifting from 1st gear into Reverse (vehicle not moving). This seems to reset the tranny such that you get great shifts for the rest of the day.

So before shifting into Reverse, shift into 1st gear and then into Reverse (all in one motion).

Likewise, it helps to start the car in Neutral, stop the car in Neutral, as well as to shift into 1st gear when the engine is off to "Park" the 348.


Improving the 348's handling via the transmission/differential


To get the differential out of the tranny case you do need to remove the bearing on the passenger side and then rotate the differential so that the big ring gear is facing the front of the tranny; then you can take it out. Otherwise you're gonna have to disassemble the differential inside the case, and that will be a big time pain. Thanks, ernie

Static slip is the resistance that you feel when trying to turn one wheel while the other wheel is held still.

Bearing preload is the resistance that you feel when trying to turn the differential in the gearbox casing (with crownwheel removed).

To measure static slip... With tranny out of car - First, remember to oil your differential while testing the slip. Now, set up an output shaft flange and hold it in a vice with a couple of bolts through the CV holes. Then sit the assembled 348 differential on top and put the other output shaft flange on the other side. Next, use a torque wrench to turn the free output shaft while the other is clamped still in the vice.

Adjust the torque wrench until it clicks at the point of slip..... You have just measured your static slip.... probably about 25-35 lb/ft on an old 348 differential.

Now, strip the differential again and add shims (home made is fine) to a non moving surface (behind the cone washer or first cross plate), reassemble and repeat the test to re-measure the static slip.

Set it to between 40 and 50 lb/ft and it'll feel great on the road, give better traction with no ill handling effects.

Remember to oil it while testing this!

Thanks, FerrariFixer

To measure static load/slip with tranny still in car - simply jack up only 1 rear wheel and turn that axle with your torque wrench on the 36mm hub nut (wheel off) to view the load on your torque wrench gauge. To test condition: with car in "N", hold one wheel, the other should turn only with great difficulty. Thanks, Rifledriver


Common F355 F1 Transmission Points of Failure: F1 transmissions will burn up the clutch if an F1-equipped car is put into reverse to back up an incline. F1 transmissions will drop into Neutral while driving if the transmission overheats (no warning). F1 transmissions will drop into Neutral while driving if the engine bonnet cover's latch sensor signals that it is open (even if it is really closed). F360 F1 transmissions will shift into Neutral if this output shaft breaks (see picture):

Thanks, ROLOcr

Ferrarifixer reports that the relay for the F1 pump is also a weak point.

Why is it so important to follow the proper Starting and Warm Up Procedure? Because if you don't you will have a cold gearbox where the selected gear is going to get hot quicker than the mainshaft (affecting tolerances),

potentially resulting in -------> Broken 360 transmission Photo by RifleDriver


 Return To Index


Hard Start

A common Ferrari 348 issue is a "hard start" problem. Any 348 that takes more than 20 seconds to start can be considered to have a "hard start" problem.


First, check the easy things. Is the ignition key not turning? That's often caused by the anti-theft steering wheel lock. Turn the steering wheel just a tiny amount (to relieve pressure) as you turn the ignition key to Start.

Likewise, the 348 will prevent your ignition key from turning forward if you've had a "false start." Simply turn the key back to Off/Position 0, then proceed to start your car. Fixed your problem? If not, then continue below.


There are 3 primary causes of hard to start conditions:

1. No spark. 2. Incorrect Air / Fuel Mixture (Not enough fuel. Too much fuel. Not enough air. Too much air.). 3. Incorrect Timing.

These conditions may occur at any time, or only when the car is hot, or only when the car is cold. When your 348 is hot, the Ferrari "cold start" circuitry will cease to be engaged during startup and idle, thereby causing different behavior in your car based upon engine temperature. Your "cold start" system can both mask and/or cause issues, based upon circumstances.

A fast "click, click, click" sound from your starter, but the engine not turning or starting, typically means that you aren't getting 12 volts to your starter (e.g. bad battery, circuitry problem in ignition key area, cable problem to starter, etc.).

348 Won't Start (engine won't turn over) At All - No Starter Motor (engage ignition just get a click) - Easy Repair (thanks Miltonian)

*Also, in addition to Miltonian's permanent repair solution to the starter problem, simply applying Stabilant 22A to the starter motor electrical "blade" connections, to the battery terminals, and to the ignition connections on the steering column can fix this issue at times.

Bad Starter Motor? 3 hour 348/355 Starter DIY Refurb Thanks, Terry!


Is your engine turning when you turn the key to Start, but not starting up and running properly...or is your engine not turning (e.g. "click, click, click") at all?

There is an *easy* no grease/dirt on the hands preliminary test to perform if your car only has a problem starting up when hot, delay/skip the primary tests and first perform the preliminary test (again, only for cars that have trouble starting when hot, not cold):

348 Won't Start When The Engine Is Hot (starter turns engine, but engine doesn't "catch" or run)

Preliminary Test: For a test, start the 348 when it is cold, drive it until it is warm/hot. Now turn the ignition off and as soon as the engine has stopped, immediately try to start it up again. This will make two "starts" in sum.

This test should help you pinpoint if the problem is a failing battery (cells can fail when hot that work when cold), flywheel grease issue (see primary tests below), or fuel pressure regulator/leaky fuel injector/check valve...because:

1. if the car does immediately start back up when hot per above 2nd start, then you probably have a fuel pressure issue (e.g. fuel pressure regulator/leaky fuel injector/check valve/fuel pump, etc.). This is because it takes a minute or two for even a failing pressure component to allow the fuel pressure to drop after the engine stops, so a quick restart of the engine when hot inside that first minute would cause the whole engine system to behave as though you didn't have a fuel pressure leak (faulty component hasn't had time to bleed away fuel pressure yet).

NOTE: Fuel pressure regulators are Ferrari part number 147281 (Bosch #0 280 160 731 available for $138 at, about $440 each at Ricambi or an outrageous $500+ at Ferrari dealerships. But...I'm reasonably sure that they are just AC Delco FP regulators. The AC Delco part number is 217-2119 and the GM part number is 35476530. You can get them for $81 each here if you don't mind forgoing the pretty yellow Ferrari shipping box: . The STANDARD MOTOR PRODUCTS FP Regulator # PR171 (~~$75 at should work on our 348's, as well. The AirTex Fuel Pressure Regulator for our 348's is only $59 at, too. These fuel pressure regulators should all be exactly the same, and interchangeable at will.

However, 1993+ 348's use Bosch Fuel Pressure Regulator 0 280 160 738, instead ($75 at  The difference between the 2 FPR's is the 731 regulator uses a rubber hose clamped with a hose clamp. The 738 version uses hard compression type fittings.

How To Change 348 Fuel Pressure Regulators

2. if the car has great difficulty starting back up immediately, then fuel pressure isn't the likely issue and instead you probably have a flywheel grease problem or bad battery.

2a. Listen to the transmission as the engine stops. Do you hear a pronounced rattle as if rocks were inside a tin can that was being shaken? If so, could be a Flywheel Grease (or related leaky seal) issue.

2b. Have your battery load tested.

2c. Swap how you started your 348 when hot. If you tried re-starting it with clutch depressed, transmission in gear, then swap and instead try a 3rd start when hot with clutch pedal NOT depressed but transmission in Neutral, or vice-versa. Also, be sure that you are turning your ignition key to Run, not Start, for at least two seconds before turning your key to Start (let the fuel system charge up).

Hope this helps!


Primary Hard Start Test (for both hot and cold engine hard starts) for engines that turn/crank but don't actually start running: spray starter fluid directly into the air intake and crank the ignition.

1. If the engine starts up but soon thereafter dies, then you know that you do not have a Spark problem, Flooding problem, or Timing problem. The likely cause would generally be a fuel starvation issue.


2. If the car starts and then runs flawlessly after first using starter fluid, then you probably have a weak spark issue (often caused by lack of a good ground cable from your metal frame to your transmission).


Secondary Hard Start Test: remove one spark plug and examine for spark (wear 2 pairs of *thick* gloves to avoid being shocked and place/tape the spark plug to the top of the engine) while a helper briefly cranks your ignition. This test will identify a spark problem or not.

If you don't have a spark then check the fuses under the passenger footwell labeled centr.injezione cyl 5-8 and the 1-4 (two fuses). Thanks, FBB

Undo the mounting screw at the upper right corner of the footwell fuse panel, then wiggle the panel out of the way, as shown in the picture below. Look at the wiring connector behind the fuse panel (as shown by the famous "pool cue"). Check to see if either of the nuts attaching the cable terminals are loose, or if you can detect any kind of a problem with the wires, such as burnt insulation or melted plastic. Thanks, Miltonian

Bypass the battery disconnect switch and give it a try.

Kingsdare had the same "no spark" problem; turned out the battery disconnect switch was only rated for 100 amps continuous. I replaced it with one rated for 250 amps from Summit Racing to get spark again.

Other "no spark" problem areas could be your two power transistors and your two ignition coils, as well as the circuitry for the ignition key fore of the steering wheel.


Engine starts Then Dies

Engine turns over, starts to run (1 sec max), fires a couple of times, and dies. Almost like it starts to run but can't idle and dies. Very rough when its doing it. No Check engine, No Slow down. This repeats every time.

Typical problem: MAF Connections. If a MAF is disconnected or loose, it'll shut off fuel pump as soon as 348/355 starts. Most likely MAF, but could be other. Thanks, Plugzit


If you do not have a fuel starvation issue and do not have a spark problem, then the usual remaining problem would be a Timing issue (crank sensor/crank sensor wires, phase sensor, cam alignment, ECU or ECU chip problem, etc.).

Hard-to-Start problem areas:

Air / Fuel Mixture: Too lean or too rich could cause a hard-to-start problem. Adjust via the screws beneath the blue caps on the MAFs (see the performance Tuning section on setting your A/F mixture). Also, check to insure that your air filter and intake passage ways are unclogged and free flowing. Verify that you have gasoline in your gas tank.

Fuel Pressure Regulators. Remove the vacuum line and inspect inside for fuel. No fuel inside = good. Fuel present = bad. Replace if bad. You may also need to test the fuel pressure inside the fuel rails. Replace both fuel pressure regulators if this pressure is too low.

Fuel filters: dirty fuel filters can cause hard starts as well as stalls when driving.

Vacuum lock: hot fuel rails can create a vacuum condition that impedes fuel injection. Consider insulating or shielding your fuel rails. Consider switching to higher flowing catalytic converters (emit less heat).

O2 sensors. Failed or failing O2 sensors can cause hard starts, stalls when running, runaway idle conditions, etc.

Fuel Return Valves: your 348 has one-way valves that prevent the fuel in your fuel rails from draining back into your fuel tank. Should one or more one-way valves go bad, you could experience hard starts if you attempt to start the car without charging the fuel rails back up (see section on how to start a 348).

Fuel injectors: a leaky injector can flood a warm engine (but gas evaporates by the time the engine cools off, permitting cold starts), causing hard starts when hot.


Fuel pumps: too little pressure from a dying pump will cause numerous 348 problems.

First, a few words of warning:

If you are thinking of doing that mate, please don't!!! The fuel pumps may and probably will explode! Have seen/heard it done before, causing serious injuries! Once a fuel pump has been used in tank, NEVER remove it and test it/power it up on bench (i.e. a so-called "dry" test). The little sparks from the electric pump, coupled with the fuel/vapour left inside the pump can/will make it burn/explode. DANGEROUS! If you are to test a used fuel pump removed from a car, fill a bucket/container full of fuel and drop the fuel pump in there. Make sure the fuel pump is totally 'drowned' in the container of fuel!! Honestly, don't even attempt to do that. The best way to test the fuel system is borrow/beg/steal a fuel pressure tester with flow gauge. Tee that into the fuel system and go from there mate. This checks fuel pressure and the flow gauge will tell you how much fuel flow you have. Most fuel problems will either have fuel pressure, but no flow. Or have fuel flow, but no pressure. Please try this 1st mate. Do NOT run them pumps on the bench dry buddy! Dont want you or someone else to get hurt!! - thanks, Pap 348


Before replacing a fuel pump:

Check your Crank Sensors: a bad crank sensor or connection will prevent a 348's fuel pump from running because 348's have a safety mechanism in each ecu that only allows each fuel pump to run when the engine is turning at 30 RPMs or greater.

Test the fuel pump relays. It's very easy to do the 348 fuel pump electrical checks at the footwell panel. Let's say you're checking for power to the fuel pump on the right bank (1/4). You're looking at relay "N" (3rd from the right on the lower row) and fuse 19 (6th from the left on the lower row). It's important to note that the electrical power flows through the relay, to the fuse, to the pump. It does NOT flow through the fuse, to the relay, to the pump. So the first test is to hook up your test light to fuse 19. It will show no power when the key is off, and no power when the key is in the "run" position before you start. But once you turn the key to the "start" position and the engine starts to crank, then you should have power to the fuse immediately, and from there to the pump. Once the engine starts, the power to the fuse is constant.

You can run power directly to the fuse, even if everything is shut off, by removing relay "N" from the panel, and using a jumper wire to connect terminal 30 (battery power, the top terminal) to terminal 87 (the bottom terminal, runs to the fuse). See my picture below. Once you do that, you should hear the pump running.

The same test for the left bank (5/8) uses relay "C" and fuse 8.

If you can't hear the pump running when you do this, then either:
- There is no power at terminal 30
- The fuse is blown
- There is a break in the wire between the fuse and the pump
- The pump is dead
- The pump isn't grounded

Terminals 85 and 86 on the relay use the signal from the Motronic ECU to close the contacts between terminal 30 and terminal 87.

This may sound complicated, but these are very simple steps.



Here's what you do to test the fuel pump relays, see pic above (however, the picture literally shows the oil pump fan relay being so tested).

Pull out each fuel pump fuse. Make sure it isn't blown, coat it with Stabilant 22a, and put it back in.

Pull out each fuel pump relay.

There are five slots in the relay panel for the five terminals on each relay. Take a jumper wire with two male spade terminals and jump the two positions shown in the picture (top center to bottom center, terminal 30 to terminal 87). It doesn't matter whether the ignition key is on or off.

As soon as these terminals are connected, the fuel pump should come on. If it doesn't, then there is a problem either with the wiring, the pump, or the ground. If it DOES come on by jumping the terminals, but never comes on any other time, then we can look at some other possibilities. Thanks, Miltonian

*as a general rule of thumb, the above hard-to-start issues are listed from least expensive to most costly. It is generally accepted that you should try the least expensive fixes first, working your way to the more expensive solutions only if the others fail.

348 fuel pump rebuild pictorial


348 starts cold, but won’t start up when hot? For a test, start the 348 when it is cold, drive it until it is warm/hot. Now turn the ignition off and as soon as the engine has stopped, immediately try to start it up again. This will make two "starts" in sum.

This test should help you pinpoint if the problem is a failing battery (cells can fail when hot that work when cold), flywheel grease issue (see below), or fuel pressure regulator/leaky fuel injector/check valve...because:

1. if the car does immediately start back up when hot per above 2nd start, then you probably have a fuel pressure issue (e.g. fuel pressure regulator/leaky fuel injector/check valve/fuel pump, etc.). This is because it takes a minute or two for even a failing pressure component to allow the fuel pressure to drop after the engine stops, so a quick restart of the engine when hot inside that first minute would cause the whole engine system to behave as though you didn't have a fuel pressure leak (faulty component hasn't had time to bleed away fuel pressure yet).

The Flywheel Grease Fix For Some Hard-Starting (when hot) 348 problems (Thanks to Miltonian and others)

Summary: the Hall Effect sensor on 348's tells the Motronic A/F ECU when TDC is reached in cylinder #1. This sensor is sensitive to vibration (as are the two Crankshaft Position sensors which can cause a similar hard start problem). An unbalanced flywheel (e.g. little or no grease left, broken internal damping parts, etc.) can interfere with normal operation for this sensor, which in turn causes 348 ECU's to not send a firing signal to the spark plugs. This is a spark problem that can occur when hot because the remaining grease becomes thinner with heat, allowing additional vibrations that aren't seen when cold.

One test to determine if this is your problem, simply shift into 1st gear and depress the clutch. If your 348 starts when warm this way, but does not start when warm while in Neutral, then you may need flywheel grease repacking or some other flywheel fix such as resurfacing. See also: . Another test is to pull a spark plug and examine for a spark while a partner briefly cranks your ignition.

Also, the Phase/Hall Effect (beneath right side Mass Airflow Sensor) and Crankshaft Position sensors (underneath engine near firewall) have electrical connections to the main wiring harness which further connects them to your two ECU's. All of these electrical connections should be coated with Stabilant 22a or "Corrosion Block" in order to establish better electrical contacts, reduce vibrational sensitivity, and protect against corrosion. Likewise, the power and triggering cables that go to both spark plug control units should be treated with a corrosion block, as should the fuses in the passenger footwell and driver-side trunk. Stabilant 22a alone, with no other work performed, can completely solve many 348 hard-to-start problems. Note: your 348 will start even with the Phase/Hall Effect sensor disconnected.


Light backfire (through air filter) when revving: lean mixture in one or more cylinders. This is a classic symptom of it. Because this is an injected car, you probably have a plugged injector. Pull all the injector nozzles and soak them overnight in carb cleaner. Blow them dry and inspect. Re-install. Then run a half tank of fuel with Techron fuel injector cleaner through the car. You would be surprised how well this stuff works. (Techron is the only brand most F-Owners endorse). It is very typical to get "popping" through the intake when the mixture is lean due to a clogged injector.


Misfire/Misfiring 348: often caused by crankshaft position sensors that need their electronic cable connections cleaned (then apply Stabilant 22A).

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Convertible Top

348 convertible and 348 targa tops are considered identical to 355 convertible and targa tops by most owners/mechanics/fabricators/replacement shops, however, the forward latches on the targa tops are **different** between 348 and 355 series.

U.S. 348 convertible top leather boot covers also have one difference from the 355 leather boot: a Velcro center crease for the U.S. 348's center-mounted seat/shoulder belts.

Replacement 348 Spider Cloth Convertible Tops (~~ $950) Past Cloth Top Example On eBay

How To Lower The 348 Convertible Top

Ferrari F-355 automatic top trouble-shooting:

F355 Top Stuck Half-Way (fix)

If your 355 auto-top is having problems lowering or raising, check the center bar that runs across the entire length of the top. On the manual 348, this bar must be pressed up to lower the top and pressed down to raise it. On the F355, this same bar may become stuck or wedged, requiring manual intervention.

Other problem areas for the 355 top include running out of hydraulic fluid. Check your hydraulic fluid reservoir and fill if necessary. There is also a bypass switch in the 355's center console that will lower/raise your top even if the position switch on your driver/passenger seats has malfunctioned (a typical problem).

In order to get your F355 top down you may have to resort to the emergency tools. They are located next to the parking brake (or in your tool kit). The top mechanism bolt is located behind the left-side seat. As you turn it, the top will raise or lower.

In order to bleed the F355 hydraulic top system I put the top into full down position and then held the button in the down position for about 10 seconds (with bleed screw open). Then put it up and continued to hold it for about another 10 seconds (while keeping the reservoir full of fluid). I did this twice and the top works perfectly now. Thanks, Dmoore

SACHS Part # SG437009
348 Spider soft top replacement shocks ($30) at

Ferrari 348 Spider: Boot Cover: German Canvas Ferrari 348 Spider Convertible (1993-1995)Boot Cover Made in German Canvas. (re-use tenax fasteners)Factory Colors: Black or Blue other colors... $825.00

Ferrari 348 Spider: Boot Cover: Leather Ferrari 348 Spider Convertible (1993-1995)Boot Cover Made in Leather (re-use tenax fasteners) $1,084.00

Ferrari 348 Spider: Boot Cover: Sonnendeck Canvas Ferrari 348 Spider Convertible (1993-1995)Boot Cover Made in Sonnendeck Canvas. (re-use tenax fasteners)Factory Colors: Black or Blue $750.00

Ferrari 348 Spider: Convertible Top: German Canvas Ferrari 348 Spider Convertible (1993-1995)Convertible Top Assembly Made in German Canvas With Plastic Window. Factory Colors: Black or Blue $1,017.00

Ferrari 348 Spider: Convertible Top: Sonnendeck Canvas Ferrari 348 Spider Convertible (1993-1995)Convertible Top Assembly Made in Sonnendeck Canvas With Plastic Window. Factory Colors: Black or Blue... $892.00

Protecting the 348's Cloth Top a product called 303 fabric guard can be found in marine stores; works great, doesn't stain, it's the only one recommended by raven mills (Sunbrella) fabric co. (thanks, MDShore348)

Fixing a shrunken leather convertible boot cover: I hand rubbed a bunch of LEXOL leather conditioner and then kept it inside a garbage bag for about a week. The leather came out a lot better and I still do this occasionally. I also keep it inside the house when not in use. Thanks, Spidey

 Aftermarket convertible tops will *NOT* come with the Ferrari Cavilino (prancing horse) emblem etched/embossed/branded onto the lower right corner of the plastic rear convertible top window. Thanks, No Doubt!

Special Products For Cleaning Rear Plastic/Vinyl Windows


Convertible Top Fasteners: Most have the plain (chrome) Tenax fasteners. You can get replacements at most any automotive/boat upholstery shop. They are not expensive. They are commonly used by other manufactures to secure covers for cars and boats. If you get the black style ones (I have not seen them) they may be like the ones used on the 328 covers, they had a horsey molded into the black plastic, were only available from the dealer, and were expensive.

If yours are rusty looking, I would just get fresh ones and call it good. If they are hard to install/remove, I would suggest putting a single drop of oil inside each fastener, it should help. carries them in stock.

They are easy to replace, you will need split ring pliers...insert the tips into the two holes on the back to unscrew them. (Thanks, DaveHanda)

Tenax Installation Key (thanks, davehanda)

Misc Items_: Tenax Fastener (Female) Tenax Fasteners (Female Side Only) Available in Black or Chrome (each) $8.35

Misc Items_: Tenax Fastener SET Tenax Fasteners (2 piece set, 1 male & 1-female) Available in Black or Chrome (priced for each 2pc set) $11.65

Misc Items_: Tenax Studs (Male) Tenax Fasteners (Male Side Only) Available in Black or Chrome (each) $4.15

The rear, center, mystery convertible snap: What goes there is a piece of Velcro (the "grabby" hook part) and it has the snap on it. You snap it on, and then push the top cover into hold it in place. I have the piece, but it does not work well at all. I ended up removing it and storing it away. Pretty worthless...thanks, DaveHanda

 (picture by MJSDAS)


Washing/Sealing/Re-Dying Spider Top

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3x8 Speedometer Calibration


Speedo Repair

First, determine if your speedo problem is in the speedometer gauge itself or in the remote "sender" pulse generator unit that is mounted on the tranny:

Your speedo sender pulse generator has a twist/pull plastic electronic disconnect near your left rear shock, so disconnect it (just for this test)! Once disconnected, start your car and while idling check to see if your speedometer is still winding clockwise and odometer adding miles (or still duplicating whatever bad behavior/conditions were being displayed previously)...

If yes, then the problem is inside your speedometer gauge (likely an IC failure in one of the pulse counting chips - see below for fix).

If no, then the problem is typically your pulse generator sender part.

This is a free test. With Ferraris, it's generally best to do the free tests first before buying/changing parts (maintenance costs can add up!).

The 348's old and expensive ($155) Ferrari speedometer pulse generator sender part # 116987 (mounted on transmission left side) is superceded by the Maserati part # 393650106, which retails for less than $50 at Do not use the old Ferrari part for a replacement unless you find it to be cheaper, use the new Maserati sensor (it is identical in every way except price, including the numbers stamped onto the part). You must also buy and install a new gasket/washer with either new speedo pulse generator/sensor. The gasket for it is Ferrari # 10263460.

Use a 32MM socket with a long flex handle to break the seal of the sender's crushable washer/gasket to get that sucker out of the tranny (you can do this job from the top without jacking up your 348, no less). Thanks, glpellegrino

348 Speedometer/Odometer Repair Tips

The electronic parts that comprise 348 gauges are generally inexpensive. Parts R Us carries the speedometer gauge IC (HCF4024BE) for sixty cents, for instance:

 After studying the diagram and comparing it against my 348, I've made up this chart. It's somewhat simplified, but I don't think any of the other wiring is really involved in making the speedometer work.

12 Volt battery power goes into the fuse panel on the right kick panel. When the ignition switch is turned, relay "e" closes and sends power to fuse #6. The power from fuse 6 is sent to the speedo head through one green/white wire, and to the speedo sensor on the transmission through another green/white wire (with a few stops along the way). This wire goes through the connector by the left rear shock absorber, and through the connector right next to the sensor. A red/black wire comes out of the speedo head and runs to the fuse panel on the right kick panel. It runs through the panel, but not through any fuses or relays. When it comes out, it is now a red/white wire which runs through the connector by the shock, through the connector by the sensor, and into the sensor.

The way I read it, the sensor takes its 12volt input signal and sends out a variable signal, depending on the speed it reads on the transmission gear. This signal goes to the speedo head, which compares it to another 12volt signal, and gives a reading on the needle.

The other wires on the speedo head connector are power sources for warning lights and voltage supply for the speedo illumination. I don't know what the white wire at the speedo plug is for. It shows as a blank in the diagrams. My guess would be that you snipped the wires when the ignition was turned on and ran full 12 volts through the red/white wire when the cutter contacted the wires. This must have fried something in the head. With my test light, I got power at the green/white wire on the speedo head and at the green/white wire on the sensor when I turned on the ignition. I hope this helps. *thanks,

Ferrari348Turbo says that the Transmission-mounted speedometer pulse sensor outputs a square wave. No Doubt says that means you'd need a frequency to voltage converter (e.g. AN-279/AD650 IC; calculate component values here ; this will give you an analog voltage output to drive a needle/meter) or binary up counter IC (plus a timer) to begin to translate the signal into a speed (e.g. HCF4024BE). HCF4024BE is a CMOS counter, 14 pin DIP IC that can handle analog inputs up to 24Mhz (gives a digital output of the current count of square wave input pulses).



A bouncing tachometer needle can be caused by a failing alternator (or alternator voltage regulator). Thanks, RoloCR

The tach receives its signal from the 5-8 ECU, which gets its signal from the 5-8 crank sensor that is mounted just above the forward-most, front-side-mounted engine oil drain.


Cruise control options can be added to your 348 for as little as $90:

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Air Conditioning and Heating and Fan/Clock

A/C & Heater & Fan Error Codes:

E1 - Passenger compartment temperature sensor - My E1 problem was solved when I worked Stabalant into the ground connections on the left front bulkhead behind the a/c outlet on the dash. *thanks, Markie1949
E2 - Outside temperature sensor
E3 - Cooled-heated air temperature sensor
E4 - Evaporator temperature sensor
E5 - Motor for heater valve control
E6 - Motor for air distribution control
E7 - is the code for the fan speed control unit (i.e. the power supply for the fan blower) - unless there is a poor connection to the unit it will have to be replaced. The part number is 63307200 and costs £166.00 @Ferrari, £110 at
Eurospares , $260 at Ricambiamerica. *thanks, Ferrari_Tech
E8 - Electric water pump for heating = Bosch #0 392 020 007 or Bosch #0 392 020 002, Ferrari #61787900 (new=#70000900)

E9 - Engine/oil/water Too Hot to continue running A/C (this is a protective shut-off that won't reappear when the engine is cold) *thanks, No Doubt

Diagnostic Mode

The electronic A/C & Heater control unit (ECU) has a diagnostic mode for further trouble-shooting.

 A/C Control Panel Figure 2

Turn the ignition key to Stop/Off. Hold down button #13 while turning the ignition key to Run (not Start). This enters the A/C & Heater diagnostic mode, reaffirmed by the automatic testing of the A/C & heater LEDs (they'll flash).

Once in this Diagnostic Mode, button #16 cycles between any of 4 test phases (simply press button #16 three times to enter the third phase, etc.).

Mode 1. Check LEDs. Press Button #15 to alternate the LED test pattern to verify if any LEDs are non-functional.

Mode 2. Check A/C & Heater control panel buttons. Once in this mode, simply pressing any button on the control panel will display a code in the temperature display. If a button doesn't change the display to the correct code (the actual code really doesn't matter, either a button changes the code in the display or it doesn't...but if you must have the code, it is in the Workshop Manual), then the button is defective.

Mode 3. Sensor Check. Press one of the buttons highlighted in blue in the following table. Doing so will give you a code readout in the temperature display that corresponds to the temperature/value/motor position that the desired sensor is reporting to the system. These codes are detailed in the factory workshop manual Table 7.


Mode 4. Actuator Check. This diagnostic mode allows you to select and test any of 5 sensors corresponding to the buttons on your A/C control panel shown here:

Once selected by pressing an A/C panel button from above, you may then move these actuators forward and reverse by pressing the up and down temperature arrows (buttons #2 and #4 from figure 2 above) as desired. You may also stop the actuator in any desired position by pressing the same panel button a second time (i.e. two "ups" equals "stop").

You may also press the up and down fan speed control buttons (#5 and #7 in figure 2 above) to operate your fan blower at any time during your test.


*348 AC Error Code E5


The Heater Control Valve that causes the E5 error code is supposed to be $1,000 new from Ferrari ($700 new at EuroSpares). It is made up of two removable components: a small electric motor and a plastic valve.

The silver/metal electric motor on top of the above two-part heater-control-valve is Bosch part #0 390 721 006, which is the Saab 9000 P/N 9625435 at $139.00 (always good to be able to walk into a local Saab dealership for parts when you don't have a Ferrari dealership in town). It's also available on-line for 73 Euros.

The black plastic valve second half of the above (pencil is touching it in picture) costs $10.50 new and typically fixes this error code and underlying problem. *thanks, ferrarioldman

FYI: the Ferrari part number for the two E5 parts combined is: 63306400 (#8 in diagram above)

The dealer took apart a 355 & said the valve correctly showed 5 Ohms when closed. But my new one went to infinity, so that's why they think it's bad & still creates the E5 error code. - thanks, Mike in ATL



** E6 = Motor for air distribution control.
It's item #13 on this diagram. It opens and closes the flaps on the heater box that direct air to the floor, dash vents, and defrost (NOT the fresh air circulation). The motor is located on the right side of the heater box, above the passenger's feet. You can reach up and touch it, and you can see it with a flashlight. If you turn on the ignition and push the A/C control buttons one by one, you can feel and hear the motor opening and closing the flaps. It takes about 3 seconds to go from one mode to another. If you don't hear the motor working, there's probably an electrical fault in the motor or the wiring. If you hear the motor working, but there is no change in the direction of the forced air, then there is something wrong in the flap system. Sometimes A/C problems correct themselves if you unplug power to the A/C for a few minutes, then plug it in again to reset the system. *thanks, Miltonian

E7 Fan Power Supply Pictures


348 A/C - Heater Schematics (scroll down past post #4)


348 A/C and Clock Fixes (thanks to Henkie, Chrisx666)

348 Climate Control Unit Repair (thanks to Rayman)

I AM VERY HAPPY! (thanks, Angelo348tb)

Also, keep in mind that rubbing electrical connections (especially the common ground crimp pin connections behind the left-most interior plastic air vent - see Miltonian's picture) with Stabilant 22a (available at typically fixes most A/C and clock problems.

The Hidden 348 A/C Fuse (and repair) (thanks to JRV)

 (the hidden A/C fuse is brightly lit near the center of picture by No Doubt, this is next to the ABS computer and relays, high on right side of front trunk/bonnet, under the felt liner)

 (lifting front felt liner to view hidden A/C fuse, ABS computer, et al. by Miltonian)

Complete Universal Fit Aftermarket A/C Systems

Ferrari 348 A/C Makes Loud Scream When Turned On + Fix

Ferrari 348 A/C Recirculation Flap Repair (thanks, JRV)

Ferrari 348 A/C Recirc Flap Repair II (thanks, Paul Hill)

Superior Recirc Flap Repair Kit/Part/Pin


Converting From Freon (R12) to R134a:

You first need to drain all the A/C compressor oil from the compressor and replace with the right amount of R134a compliant oil. This is very important or you will have big problems. If the system has been non-pressurized, you should replace the drier canister because it will be saturated with moisture. Then you swap out the fittings for the R134a fittings and draw a good vacuum on it to remove all the moisture and test the fittings. Once that is done, you then can fill with the right amount of R134a gas. The whole process can be done in a couple of hours if you have the tools and contrary to what people say, the Ferrari A/C system on this car works perfectly well with R134a when done right. Thanks, Birdman

I had my 348 converted during it's last service when they changed the A/c oil and the A/C gas. The engineer did tell me that although the conversion works well, that the R134a molecules are much smaller than R-12 so the system will probably need a re-charge every couple of years as the 'seals are designed for R-12.' Thanks, madjules

I had my '85 308 done over the summer. The drier was bad, so I figured it was time to convert anyway. New fittings, new drier, new oil, new Freon, and new O rings. Apparently the R134a doesn't do well with the old O rings used on the R12. No big deal, but you might as well do it while you are in there. Thanks, dpospres

Vintage Air recommends the use of a charging station when doing any type of service to your A/C system. These machines are more efficient and provide the highest level of accuracy when charging by volume.

R134a should be charged by volume, not by sight glass readings - there is no guarantee that the bubbles will disappear from the sight glass, regardless of charge, with R134. Using the manifold gauge method worked fine for R12, but R134a is extremely charge sensitive.

 photo of A/C nozzles in front trunk under left side felt liner thanks to 3forty8

As a rough rule of thumb, I try to get the temp at the vent to about 4 degrees Celsius, that is with the thermo stat at full cold and the blower fan on the lowest speed to allow the air to absorb the coolness off the evaporator. As for the head pressures, I find if I run with between 10-18 PSI on the LOW and 180-240 PSI on the HIGH it's not a bad median for a cool vent temp. The rest is just trial and error. Thanks, Pap 348


With r134, the lower the charge, the lower your temp (within reason). This site says charge r134 to 90% of full r12 pressure for your vehicle (i.e. 10% less than R12):

This site lists an r134 pressure chart:

Low Side PSI, ..Evap Temperature (F), ...High Side PSI, .....Ambient Temp (F)
16-29 .............. 33-50 ............. .............. 115-200 ............. 70-80
19-39 .............. 33-60 ............. .............. 140-235 ............. 80-90
25-43 .............. 40-65 ............. .............. 165-270 ............. 90-100
37-51 .............. 48-65 ............. .............. 210-310 ............. 100-110

A/C isn't cold? Check the basics first

1. In your front bumper, look deep into the cut-out on the U.S. (right) passenger side. Make sure there are no leaves or junk stuck on the condenser.

2. Inside the bonnet, look deep inside the airbox (right against the windscreen). Make sure the car is off, but stick your hand inside there and make sure there are no obstructions or things that fell inside. Does the recirc flap work correctly in your car? Press the button on your HVAC panel and see if it opens and closes in that airbox.

3. You might want to pull your airvents out from the dashboard and make sure the "open/close mechanism" is indeed working correctly. With the vents removed, do you get any air coming from the dash?

The system in the 348 is pretty simple, so tracking down the problem should not be too difficult. Just be sure to only stick your hand into the bumper or airbox when the car is OFF! Thanks, Jack Russell Racing


A/C Isn't Cold And You've Checked The Basics Already?!

Your 348 a/c should be more than adequate to cool your cabin. Its really easy to add "freon" to your car. All you have to do is get a coolant adding kit that has the built-in gauge. Hook it up to your car while the engine is running and the a/c is on full blast. If the pressure is fine then it is indeed just the way your car is but I bet that's not the case. You probably need to add some. Its really easy, you just screw the can onto the connector until it punctures the can, then hook it up and check pressure. If the gauge says add then all you do is very slowly unscrew the knob until you see the needle start to rise on the gauge until it gets to the red high pressure zone. You may have to do this a few times until the gauge gives a constant read where it needs to be.

I just did it today in fact to my Mondial and it blows ice cold now. Really it does! The kits usually have a sealing element as well as oil to help your a/c internals and help stop any leaking. I think mine has an extremely light leak but I intend on doing a once through when I do my next major service. It took a whole year before I noticed it blowing cool instead of cold.

Good luck.
-Nate Shark49


A/C Compressor Won't Kick In and/or Cooling Fan For Evaporator (front bumper inlet area) Won't Turn On?

Our 348's have compressors with pressure switches; not enough Freon (R12) or R134a and the compressor clutch won't engage nor will the front A/C evaporator fan turn on.

Add R12/R134a as appropriate. If your A/C system won't hold a pressure charge of R12/R134a, then have your system leak tested by A/C professions.

Ferrari 348 Aftermarket A/C Compressors, Dryers, expansion valve

Now that you know where to find aftermarket expansion valves, here are some tips on why you'll never need a new one. Yup. OK, so your dealer and your A/C specialist told you that your desiccant has exploded and your Expansion Valve is clogged and that you've got a big-ticket repair/replacement charge staring you in the face for your Ferrari 348, F355, TR, Mondial T, etc.

Laugh at them. Here's why:

UNCLOGGING A/C Expansion Valves

I have cleared these blockages many times. You will need a new receiver/drier. You will need a flushing agent (solvent) made for A/C systems, and you will need a device for which to introduce the solvent into the system. I use a flushing tool that is available from NAPA. Some are tougher than others to clear, but I haven't had one that didn't clear yet.

The flush that I use is called Dura 141 (NAPA part numbers 409517 for the gallon can and 409518 for the quart can). I use a clear hose on the output side that goes into a bucket so that I can tell when the all the yucky stuff comes out.

A quart of the solvent is poured into a high pressure aluminum bottle, sealed, and charged with about 130 lbs. of compressed air. On the bottom of the bottle is a fitting with a hose and rubber tipped air blower. Remove the lines on the receiver/drier and throw the drier away.

Attach a hose over the end of the output hose of the receiver/drier with a hose clamp and run the other end into a bucket or suitable container. Remove the low pressure hose from the A/C compressor.

Be sure to wear eye protection. Now using the blower on the hose of the solvent tank, sealing the nozzle tip into the end of the hose, you will blow the solvent into the system. After you have emptied the tank of solvent, use compressed air with reduced pressure, about 40 - 60 lbs. to blow through the system until nothing else come out of the other end. Sometimes you may have to do this a second time to remove the old oil and desiccant from the system. Install new receiver/drier, evacuate and charge system then check for leaks. The first TR that I had to clear the blockage, I removed the expansion valve. BIG job. Quickly figure out that this way works just as well. THANKS, FerrariOldMan!

Lolaman says that one symptom of a clogged expansion valve is the manifold gauges register a VACUUM on the low side when the A/C compressor comes on. He also says that after following the above flush advice (I did get a trace in my eyes and should have worn gloves), that it works like a champ for his Mondial T.

UNCLOGGING A/C Expansion Valves, Part Two

Before you do all of the above flush work try dumb old billybob's method. Here is the theory. If you have air in the system you have moisture. Pressure in the system under function causes icing and blockage in the expansion valve and no worky A/C. So unless you are getting gauge readings that say you are blocked, I would try this first: Remove the receiver dryer. Bake it in your wife's oven at 250 degrees for 1hr. Reinstall and make sure you vacuum out the system before you recharge it.

This works most of the time and is very easy. It works especially well with Ferraris because they do not make good A/C systems and they are always losing freon. So techs just recharge without vacuuming out the system to remove all moisture. O.K. I have just gone against all the experts but my method is quick and easy...try it. I rarely ever have to solvent flush. Thanks, fatbillybob


Repairing A/C metal tubes/lines

 broken A/C line on firewall - photo thanks to Luuk 348

If you [make a clean] cut [on each of] the broken ends back past the point where the tube is deformed [or cracked or broken], the break can be repaired by slipping a section of Aluminum tube that just fits over the break, & then soldering it on using A/C rated Aluminum solder & flux.

If there's a hose crimped to the tube, you may have to protect it by wrapping with wet rags or immersing in water.

Here's an Aluminum solder source: Thanks, Verell

 professionally repaired A/C line ($250) - photo thanks to Luuk 348


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ABS Errors: Perform a diagnostic test on your ABS system. Remove the front luggage compartment liner. On the right/ U.S. passenger side you will see the ABS module; it contains a series of relays and fuses. Looking at the fuse section you will notice 1 empty fuse socket. Install a 10 amp fuse. Turn on the ignition to light the ABS display. The ABS light in your dash will start to flash a code (a series of 1/2 second sequential flashes with 2 second pauses in between) after a few seconds initial delay. Count the flashes, note the two-digit code (codes can have values from 11 to 78). Reference the 348 workshop manual (also shown below) for the problem the code equates to (typically a simple bad electrical connection near the wheels or just low brake fluid in your reservoir). After the first 2 digit code is read, unplug the 10 Amp fuse (leave the key switch on) and then re-insert it so then the next code if any will be displayed. Repair the problem. Perform the ABS diagnostic test again to be certain, then remove the 10 amp fuse prior to driving.

Advanced ABS Trouble-Shooting

Teves Mark II and Mark IV ABS parts can be remanufactured here:

Also, the Mark II systems are shared with 1988 to 1992 Ford Thunderbirds (typically supercharged), whereas Mark IV ABS systems are shared with 1993 (and some later years) T-Birds. carries these "Ford" parts for somewhat less than Ferrari, by the way!

As an alternative to paying $3,565 (here) for an OEM Ferrari ABS replacement controller, BBA-Reman remanufactures Tevas and Bosch ABS ECU units (i.e. Ferrari ABS controllers) for $350. Used units (Ferrari part #131325) can also be found here: and keep in mind that this part was shared by the Mondial T and F355 (also here). Used Ferrari 348 (all years) and 1995 355 ABS ECU's come up for sale periodically on (usually for ~~ $600).

BBA-Reman also rebuilds Ferrari engine ECU's.

Fuel Injection Service also repairs ECU's 925-371-6551 as does Ron at Flashback Motor Works 404/435/6760 770/781/8989


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The Ferrari 348 first used the Motronic 2.5 A/F ECU system, but quickly upgraded all 1990 and later model 348's (and some 456's, 512's, Mondial's, 1995 F355's, and F50) to the Motronic 2.7 A/F ECU system, shared by Audi, BMW, Fiat, GM, Hyundai, Lancia, Opel, Vauxhall, and VW.

Motronic 2.5 and 2.7 systems "learn" your car. Based upon wear that is unique to your vehicle as it ages, modifications, and maintenance, the Motronic 2.5 and 2.7 systems compile air/fuel "maps" as you drive, when you idle, when your car is hot, when your car is cold, etc.

These computers must be reset so as to lose the old air/fuel maps whenever you modify your vehicle (e.g. new O2 sensor, new air filter, new exhaust system, change MAF resistance, etc.). Resetting the A/F ECU's will also cure some minor performance issues if the computers have learned something in error.

*Motronic 2.7 Fuel Mapping ECU chip picture credit to T-A Tech

These chips are marked "B57" for Bosch 57 fuel mapping (the map version is the number on the white tape). These are DIP chips, also called DIL chips. They cost about $4 in blank form. The IC industry labels these empty chips (when new) as either an M27C256B-10F1 or else an M27C256B-90F6, the only difference being the programming speed on your Eprom burner.

This eprom reader/burner will give you the hex dumps from these IC's, and can enable you to later contemplate making actual changes back to them to suit your 348: (costs about $120), which is worth it just for making backup chips (they do age/degrade and they can be burned up). Thanks, No Doubt

How To Change/Access Your A/F ECU Chips

Pelican Parts ( ) reports that Motronic ECU's can be swapped out between different makes and models of cars if certain matching conditions are met: "A little known secret is that many of the [ECU] units are exactly the same across different automotive manufacturers. The only thing that is different is the programming chip contained within the unit. If the [ECU] unit is the same version of Motronic, has the same connector on the unit, and has a removable chip, then chances are it can be a good replacement for your failed unit." Naturally it also stands to reason that both 348 ECU's must be perfectly matched in all aspects, as well.

For the later model Ferrari 348's using Motronic 2.7, the internal Motronic software is known as version M27. M27 software is found here: Potential Ferrari 348 ECU Replacements

"0 261 200 489" is the exact stock Ferrari 348 Spider ECU Bosch part number as well as the exact stock Peugeot 306 1.8 liter ECU (OEM part #REU0489) from 1995 on (available here: ).

Early model 348's used Motronic 2.5. Also, it's worth mentioning that the first year model F355 used Motronic 2.7, and then moved up to Motronic 5.2, the very system used on the 1996 and later model BMW 840i's. All Ferrari 348's are therefor convertible, with some effort, between Motronic 2.5, 2.7 (Ferrari, Peugeot), and 5.2 (Ferrari, BMW). See also for ECU testing, repair, and hot swaps for less than $200.

If you do swap identical Motronic 2.7 ECU's, you will want to likewise insure that both ECU's have either the Ferrari stock removable ROM chip in each, or that they both have the proper performance ROM chip installed for a Ferrari 348.

 Bosch Now Makes New "BX" ECU's that replace the old ones *also for MAFs

Also, may be able to help: 1.888.888.1417 (rebuilding your ECU:

How To Check A/F ECU Trouble/Diagnostic Codes

Reinitializing/Resetting A/F ECU's: When your engine is cold, disconnect your battery for 35 seconds (this can be done by turning your battery disconnect switch). Hook it back up, start your car, and let your 348 idle for 10 minutes (or until at least one radiator cooling fan kicks on). Do not touch the accelerator (before or during this 10 minute period). Do not self-activate any electronics during this time. Your ECU's are now "re-initialized." It's not that tough!

NOTE: Re-Initializing your ECU's is required whenever you change ECU chips or any major air or fuel or timing engine component. This process is also useful for solving some minor electrical/idling/performance gremlins.

Why do we reset the ECUs? To force the Motronic 2.7 "relearn" process.

All mechanical devices wear with age. Likewise, so do electronic and electrical components, especially those devices that are in high heat areas (e.g. O2 sensors in your exhaust flow).

This wear impacts performance. A dirty air filter, for instance, flows less air. A dirty fuel filter flows less fuel. Aged fuel injectors flow at different rates, etc.

Motronic 2.7 learns your car as you drive. M2.7 makes adjustments to your air/fuel mixture based on your car's individual wear/condition. Install a new muffler? M2.7 will learn this and make adjustments.

Each M2.7 engine ECU stores two different types of things:
1. error codes
2. individual vehicle fuel air maps

When you disconnect the battery on a 348, you erase both of the above. When the battery is reconnected, each M2.7 ECU shows no error codes and uses only stock factory air fuel maps.

As you drive, the above will be modified as M2.7 learns your car through feedback from its sensors (e.g. MAF, O2, coolant temp, etc.).

This is not an instantaneous process.

Until M2.7 completely relearns your car, however, your initial ignition timing and your initial fuel air maps will be giving your car fuel and spark as if you had a factory new, stock 348.

Of course, once your car is warm your O2 sensors and MAFs will enable M2.7 to gradually adjust your air fuel mixture as appropriate to your car, but again, this is not an instantaneous process. There will be time periods where your car isn't running at its peak capacity/refinement. It's also worth mentioning that your O2 sensors are always *ignored* by M2.7 when you are driving at full throttle.

Moreover, until your individual fuel air maps are completely relearned, M2.7 will have a more difficult time coping with a failed sensor (e.g. a bad O2 or MAF).

Of course, when you force M2.7 to go through the relearning process, all of the above is sped up to a small window of 10 minutes or less.

So the difference between driving after going through the relearning process versus driving without going through the forced startup relearning process amounts to:
1. better idle
2. better running
3. better revving
4. better full throttle performance
5. better cold engine and cold weather performance
6. better gas mileage...
...until M2.7 relearns your car's condition through enough driving. Of course, M2.7 does less learning but more acting when you are driving versus when it is going through the forced relearn process on a cold engine at idle, so expect it to take considerably more driving to complete the relearn process than the ~~ 10 minutes it would take to go through the forced relearn process.


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Oil Issues


Recommended street oil: Red Line's synthetic 5w40.

NOTE: The Ferrari 348 Spider has a dry sump for its oil system, so you only check your oil when the motor is hot; never when cold.

348 Oil Change: You will need to remove two drain plugs. One 12mm drain plug is located above/behind an underbody panel at the front of the engine just below the seats/ECU's on the bottom of the car. You will need a new copper crush ring for the re-assembly. The other drain plug is under the dry sump (requires a 22mm or 24 mm socket for this bolt) at the very back right side of the car beneath your oil fill reservoir (large black box with silver/chrome oil cap on top). The drain plugs, copper crush rings, and oil filter are all included in this bargain-priced oil change kit at Ricambi:

After those two drain plugs are opened, you will then want to disconnect/drain/reconnect the lower hose going to the oil cooler on the right side of your 348. Without this optional step, up to 1/2 quart of old oil may not be drained.

You will want to lift up the black airbox (four 10mm nuts) to more easily reach your old oil filter for replacement.

Write the date of your oil change, your mileage, and your oil type onto your new filter. Install your new filter, re-install your drain plugs (using new copper crush rings), reconnect your oil cooler hose if you disconnected it in the optional step, add fewer than 11 quarts of your new oil. Re-install your airbox. Start your engine and then check your oil level. Examine underneath for any leaks. Check your exhaust for any white or gray smoke (typically due to too much oil). Adjust your oil level as required.

One common motor oil-change mistake is to attempt to remove the oil pump pressure access bolt, thinking that's an oil drain. Plug "A" above is for access to the oil pump pressure adjustment bolt. DO NOT, I repeat, DO NOT mess with the oil pump pressure bolt. It has nothing to do with a proper oil change. You can remove the plug without doing any harm to the pressure adjustment bolt, but DO NOT FOOL with the adjustment bolt inside. It's set at the factory, so leave it be. I had to replace that plug on my 348 when I first got it. The morons that owned it before me had totally mangled the plug. The plug is made out of brass, and is cupped on the inside so that the adjustment bolt can fit inside it once the plug is screwed in. Thanks, ernie

22mm oil reservoir drain plug/bolt: 22mm or 24mm oil reservoir drain plug/bolt
22mm oil reservoir drain plug/bolt:

Another common motor oil-change mistake is to drain the transmission gear oil (marked "oilio cambio") instead of the engine oil. For this reason alone it makes sense to use an off-colored transmission gear oil such as Red Line's SuperLight Shockproof (yellow) for transmission fluid changes.


Official Ferrari 348 Oil Temperature Repair (thanks, nico)

Aftermarket 348 Oil Cooler Thermo-Switch Replacement (thanks to 348paul)

348 Oil Thermoswitch - OEM - #123277 for $60

Bosch relays (as used on Ferraris and various other makes of cars) number their metal pins with a standard category system.

PIN # = Standard

15 = Switched positive output from battery
30 = Positive output direct from battery (+)
31 = Direct to battery negative ( - ), ground
31b = Return to battery negative via switch or relay
49 = Positive input for turn signal flasher
49a = Turn signal flasher trigger power to switch (54); marking used after /5
54 = Turn signal switch contact from flasher (49a); marking used on /5
85 = Relay trigger wire, generally for negative/ground winding on electromagnet
86 = Relay trigger wire, generally for positive winding on electromagnet
86a = Path to ground via neutral switch with diode (prevents "NEU" from lighting via clutch switch [contact 86] )
87 = Normally open relay output, generally
87a = Normally closed relay output
87b = Second normally open relay output on a separate throw
D+ = Voltage Regulator/Dynamo (Alternator) positive
C or KBL = power to turn signal indicator light in gauge cluster *thanks, Airheads BMW club Joe Cuda

 Here's what you do to test the oil cooler fan - very simple (and this procedure is valid for using on other Bosch relays such as the fuel pump relays, see chart above).

Pull out fuse 15. It's the third one (see picture above) from the right in the lower row (20 amps). Make sure it isn't blown, and put it back in.

Pull out relay "O". It's the center one in the bottom row in the footwell panel.

There are five slots in the relay panel for the five terminals on relay "O". Take a jumper wire with two male spade terminals and jump the two positions shown in the picture (top center to bottom center, terminal 30 to terminal 87). It doesn't matter whether the ignition key is on or off.

As soon as these terminals are connected, the oil cooler fan should come on. If it doesn't, then there is a problem either with the wiring, the fan, or the ground. If it DOES come on by jumping the terminals, but never comes on any other time, then we can look at some other possibilities.

The thermoswitch for the oil cooler fan should close at 90 degrees C, turning on the fan, and open again at 80 degrees C, turning off the fan.

There is normally no power running to the thermoswitch or to the fan motor, so don't check for power in the back. Thanks, Miltonian


Ferrari 348 Oil Pressure Problem

Does your 348 require 3-4 seconds to build up oil pressure (i.e. oil pressure too low)? Oil warning lamp lights up during Startup? One potential cause is a warped non return valve on the French-built Purflux filter (OEM Ferrari). Older, problematic models had part #130623 or #191462, now superceded by improved part #197654.

Potential improvements include the MANN W930/13 filter (used on Aston Martin, Bentley, Jaguar, and Rolls). Also fitting the 348 are the Knecht / Mahle OC 238 filters and the WIX 51231 filter. Wix has consistently fared well in on-line "cut apart" filter tests, but may not be quite as tall as the Purflex OEM part. The factory-correct standpipe also needs to be verified for any of these potential replacement filters.

The Non Return Valve for the outdated part #130623 or #191462 is the thin black (warped) ring on the bottom right.
Credit for picture et al to Chris Fricke.


Does your oil pressure zoom to the Highest mark when you turn your ignition key to Position II (Run) before you even start your 348?

This typically indicates a loose or broken wire going to your oil pressure sender that is just in front of your oil filter (remove oil filter to access it). Contact cleaner on the sender's contact points is also a good idea.

Other causes of high oil pressure:

Overfilling will most certainly contribute to high oil pressure (which can pop an oil filter or blow a gasket or gum up your MAF or air filter or air intake). So can using an oil that's far too heavy than specs suggest. A clogged oil filter will pop up your pressure by up to an additional 8 psi before the bypass valve is activated in many cases, as well. Of course, oil pressure will always be higher when the oil is cold than when it warms up to operating temperature. Perhaps an oil change would be in order so that you know that you have none of the above issues?!

For completeness, other causes of (apparently) high oil pressure would be:
1. faulty, stuck, or misadjusted oil pressure relief valve
2. clogged oil passage(s)
3. faulty oil pressure sender
4. faulty oil pressure gage/wiring/power voltage/ground


Additional oil temperature cooling can be obtained by adding a simple heat sink (yes, like the kind used on the CPU chips inside your PC) to your oil filter. Installation is so easy that even doctors can do it.

Ferrari Oil Research (thanks, AEHass)

Professional Ferrari Techs Can Misdiagnose Head Gasket Failure As "Condensation"

oil sump photo by HarmonyAutoSport

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 Wheel/Tire Related

Original Equipment Front Tires 215/50-17

Original Equipment Rear Tires 255/45-17

Lots of 348 owners have complained of squirrelly handling when only replacing 2, instead of all 4, tires.

The general consensus seems to be that the 348 suspension is set so tight that the new tire chemical protection compound (which supposedly wears off in less than 200 miles) used on street tires upsets the overall grip equation.

So you can swap out rear race tires, but not rear street tires.

For 348's it seems to be that you need 4 new tires or none. This also means that 348 owners can NOT mix street tire brands front to back or side to side, nor can we mix tire brand models, so don't put Bridgestone RE540 on your front with Bridgestone S-02 on your rear.

Brands (from most expensive/popular on down)

1. Pirelli P-Zero ($152 each) / Pzero Asym ($227 ea), Bridgestone RE540 + RE55, Continental Sport Contact ($192 ea)

2. Bridgestone S-02, Dunlop Sportmaxx, BFGoodrich KD ($150), Toyo 888, Toyo TR-1 ($140), Continental Extreme Contact ($129)

3. Kumho Ecsta 712 rears ($99) / 712 Fronts ($100), Yokohama Advan A048's, Toyo/Falken 512/Hankook K104 ($89 ea) /Cooper

Tire Sizes you can run on 18" Ferrari 360 Modena Wheels when used on a Ferrari 348:
1. Front 225-40/18
2. Rear 275-35/18
This is the link to a tire adjustment size chart. thanks, GQ_Image

348 Wheel dimensions: 5x108mm bolt pattern, 17 inch diameter by 7.5 inch width front wheels, 17 inch diameter by 9 inch width rear wheels (shares bolt pattern with 355, Mondial, Testarossa, 360, 456).

Ferrari Wheel Widths + Offsets: *thanks, Auraraptor

328 ABS: 7" +38mm Front; 8" +63.5mm Rear
348: 7.5" +49mm Front; 9" +68mm Rear
355 Speedlines: 8" Front with +60mm offset, 10" Rear with +80mm offset.
360: 7.5" +31.5mm Front; 10" +39mm Rear
360 Modular wheel: 7.5" +31.5 Front; 10" +38.95mm Rear

456GT: Fronts are 8.5" wide x 17 with +50 mm; Rears are 10" wide x 17 with +24.6 mm

F512M: 8" +46mm Front; 10.5" +81.75mm Rear
F550: 8.5" +46mm Front; 10.5" +32mm Rear

Placing 360 wheels (18") onto a 348: the outboard edge of the 10" 360 rear wheel would be in the same position as if a 41.7 mm spacer had been added to the stock 348 rear wheel (and the inboard edge of the 10" 360 rear wheel would be in the same position as when a 16.3 mm spacer is added to the stock 348 rear wheel). *thanks, 91tr

348 Wheel Spacer Types/Settings/Sizes

Ideal 348 Wheel spacer Setup (thanks, henkie)

Wheel Spacers and Bolts For Different Wheels or Widths


348 lug bolts are sold for $6 at Grand Prix Tire, $108 at Ferrari dealerships. Same chrome cap on both. *thanks, JoTec

348 lug bolt thread is M14x1.5P (thanks, 91tr)

348 TS/TB stock bolts in the front are 55mm under the head.

348 Spider (all 348’s 1993+) stock front lug bolts are 55mm under the head (shank).

348 Spider rear stock lug bolts in the front are 80mm under the head.

348 stock lug bolts have 22mm heads (i.e. use a 22mm socket to remove/install). Thanks, No Doubt!

355 stock lug bolts in the front are 52mm under the head. *thanks, Jack Russell Racing


348 Tow Hook thread pitch is M16 2.0P (thanks, Dr.T348)

348 Static Versus Dynamic Wheel Balancing Caveats

Correct Positioning of 348 Wheels ---------------------------> (thanks, BT348PBG)



Checking your tire pressure automatically is easily achieved with an aftermarket tire pressure monitoring system such as APC's sensor and display unit combination (wires into the Accessory connection of your glove box light and Battery connection of your overhead dome light, or to your Accessory and Battery connection for your cigarette light and lighter).

APC units can be found on eBay for less than $75

Installing Tire Pressure Systems Onto 348's




Squeaking Ferrari Brakes Fixes

Surprisingly, the brake pads are directional. On the back of the pad, you'll notice that the squeal plate (that's my own technical term) goes all the way across one piston and only half way across the other. If they're on backwards, they squeal like crazy, so just reverse the offending pads -don't ask me how I know... thanks, plugzit

For non-track, pure street use, the Axxis "Metal Master" brake pads are the BEST for reducing brake noise, giving good stopping power and minimizing brake dust on 348's. And they're only $56 a pair.

348 Brake Pad Replacement Tutorial (thanks to Daniel Pass of Jack Russell Racing)

Yes, you can "turn down" or machine your 348's rotors. You'll also want to shop around for prices on 348 rotors. TireRack frequently runs sales for the 348 rear rotors (typically less than $100 each), for instance. Front 348 rotors tend to cost $250 each (or more) almost everywhere.


355 Brake Pad Wear Sensors/Repair

Brake Sensor Repair Part Two

The brake pad wear sensor is essentially just a bare wire. Normally it's just stuffed inside the brake pad material or packaged inside a cheap plastic connector that rides in a "U" groove in the brake pads (in either case it makes an electrical open connection, which is to say, it isn't completing the circuit). Brake pad wear causes the bare wire to eventually rub against the brake pad backing or rotor, both of which make a good electrical Ground connection, thereby completing the circuit to light up your "BRAKE" dashboard warning light. Thanks, AZFerrari

If your "BRAKE" dashboard warning light is lit, then be sure to first top up your brake fluid, shine a flashlight into the fill reservoir to look for debris (if found, bleed your brake system with fresh brake fluid - see below), and disconnect the front two brake pad wear sensors. These wear sensors can simply be unplugged from the 348's main electrical harness by pulling each one loose about 6 inches from the brake calipers, leaving the brake pads installed and leaving the actual sensors inside the brake pads for your test (then remember to reconnect them before driving!).

Now turn the ignition key to Run (not Start) to see if the "BRAKE" light turns off after the self-test. If not, then additionally disconnect the rear two brake pad wear sensors (leaving the front wear sensors off, still). Turn the ignition key to Run (not Start) to see if the "BRAKE" light turns off after the self-test.

This process will quickly narrow down where you have a worn or faulty brake pad wear sensor or brake pad.


Brake Fluid: Ferrari 348's can use DOT 3, DOT 4, or DOT 5.1 (glycol) brake fluid. There are natural and synthetic glycol's. DOT 5 or 5.0, however, is silicone brake fluid. Do not use silicone brake fluid in a Ferrari. Do not confuse DOT 5 with DOT 5.1. ATE Super Blue/Gold works well, as does the Valvoline Synthetic. Once a year is the recommended brake fluid change interval for street driven machines (this will help your ABS, pump, cylinder/seal lifespans and functionality). Also, it is acceptable to mix DOT 3 with DOT 4, or to add DOT 5.1 to DOT 4, for street driven 348's.

 Brake Fluid Leaks: An overfilled brake/clutch reservoir will drain in the center of the car near the front bumper.


Brake/Clutch Bleeding:

IF you have ABS, then your ignition needs to be on (engine off is fine, but ignition on) during the bleed so that the ABS pump can move the old fluid out and the new fluid in.

Generically, you check the Master reservoir's fluid level and fill to the top line, then turn on the ignition, then re-check the fluid level and fill to the top line if needed. At this point you connect your el cheapo Motive power bleeder (I love mine!) to the fill reservoir, insure that it has plenty of brake/clutch fluid in it, then pump it up to 10 PSI.

With the ignition still on you bleed the rear calipers from all bleed nipples (many have more than one, depending on the car), then the front calipers, then you stick your head under the Master fill reservoir and if it has one or more bleed nipples you bleed from there, too.

Check periodically that your Motive power bleeder still has plenty of brake fluid in it and that it is maintaining 10 PSI. Turn off your ignition and bleed the clutch (yes! bleed the *clutch* because it shares your same Master fill reservoir).

Now slowly let the air out of the Motive power bleeder, then disconnect it from your fill reservoir and reinstall the cap onto said Master reservoir.

NOTE: for my 348 I have to sometimes pump the brake pedal a few times to activate the ABS pump to get the first caliper's bleed nipple to flow, even with the Motive hooked up to the fill reservoir. No big deal, and your mileage may vary.

Bonus points if you place some rags beneath the Master in case of any overflow during the process.

Double bonus points if you use a different colored brake fluid so that you can see the new color come out of each caliper before you finish each bleed.

All in all it's an easy one-man job. Very satisfying (to me, at least).

No Doubt also suggests that you suck out with a hand pump the dirty brake fluid in the reservoir first, then add in your new brake fluid (preferably a different color) to keep topped up for your forthcoming brake fluid change (why pump that much "extra" dirty brake fluid through your system?!).


 348 and 355 Hand Brake / Parking Brake / Emergency Brake Dual Adjustments (thanks RF128706)

"The parking brakes in those are really quite good if adjusted correctly. The mistake many make is to just adjust the cable, even the factory made that mistake when the cars were assembled. The key is to back the cable adjuster way off then adjust the shoes inside the rear rotor in exactly the way drum brakes are adjusted. Adjust them until the rotor is firmly locked then back the adjuster off 4-6 clicks. Now adjust the cable for proper handle operation and the parking brake should hold on quite an incline." - thanks, Rifledriver

Aftermarket Parking Brake "Line lock"


Replacing the Parking Brake handle grip inside the cockpit: You'll need to get out your trusty channel locks and twist it off. I believe the factory epoxied them on. Ricambi should be able to source you a factory one or MaCarbon offers them in carbon. Thanks, JohnnyB


Ferrari 348 and F355 Brake Caliper Rebuild (early year 348 calipers were ATE or Teves, later years are Brembo)

Ferrari 348 Brake Caliper Rebuild Kit (Brembo Seal Kit Family A40)

Ferrari 348's (front and rear) share the same brake pads as the rear of Porsche 911's and Carrera 4's from 1991 through 1995, and for the rear of the Porsche 928 models from 1986.5 through 1995. Thanks, No Doubt

I don't know the answers to all of the questions about the 348 calipers, but one of my books suggests that the 348 uses pistons of 36mm and 40mm diameter, two of each, in each 4-piston caliper. I have scanned an exploded view of a 348 caliper.

It is possible for a 348 brake/caliper to start sticking when the pad is nearly worn to the backing plate, that's what happened on the left rear on my car. It was very noticeably dragging when the pedal wasn't applied, but once I installed new pads, with no other changes, the dragging completely went away. Apparently the pad was sitting slightly crooked in the caliper, and not releasing properly. I also just went through a problem with a collapsed brake hose (on my 1992 Chevy Pickup) this last weekend. I had installed new rebuilt calipers ($18 each !!!) and new pads on the front of the truck, and the left front brake was sticking badly. The hose looked fine from the outside, but internally it was almost totally blocked, and the wheel got too hot to touch after a test drive. The new hose cured it.

This test procedure will work as a good first check. If the brake is binding and you can get it loose just by opening the bleeder and releasing pressure, then it's at least possible that the hose is partially plugged. It could still be another problem (master cylinder, pedal linkage, etc.), but a problem in those other areas should effect all of the brakes, not just one corner. Thanks, Miltonian

Try opening the bleeder on a stuck caliper. If this releases the brake, then it's the hose to that brake that's the problem. -thanks, 2NA









Rotor Replacement

For the caliper bolts the torque is 64/Nm (6.4/Kgm). For the bolts holding the rotors in place use 20/Nm (2Kgm).

Keep it simple. Remove the wheel. Remove the caliper. Remove the bolts that hold the caliper in place and then move the caliper out of the way (you should use a coat hanger to hang the caliper so you don't mess up the brake lines), and you may need to hit it with a soft hammer to get it to come loose.

Now unbolt the rotor retaining bolts and remove the rotor (if stuck, do not strike the braking surface - use a soft hammer on the inner surface or better still use a puller). Resurface or exchange with new rotors and then replace the rotors before re-installing the calipers.

If you are having braking problems such as shimmying/shaking, consider using 600 grit sandpaper to resurface/clean your hubs while you have the rotors off.

If your rotors were difficult to remove, consider using a *thin* coating of anti-seize compound on the hub (making certain to get no anti-seize compound in any of the wheel lug bolt holes).

Ferrari 348 aftermarket brake discs/rotors:
Brembo 25261 (front): $240
Brembo 25263 (rear) : $220

Powerslot Cryo-treated 477CSL, 477CSR (front r,l): $215
Powerslot Cryo-treated 478CSL, 478CSR (rear r,l): $311



 Are Your Brakes Still Being Applied Even When You Aren't Pressing On The Brake Pedal?!

1. Could be stuck pistons in the calipers (time for new calipers or for a rebuild, see above)

2. Could be worn/stretched/aged brakes lines about to fail (e.g. swollen rubber lines, if any)

3. Could also be a failing master cylinder. One master cylinder and brake booster failure test is to cautiously see if the braking problem occurs when you press the clutch pedal along with the brake pedal, and releases from braking only when the clutch pedal and brake pedal are *both* released (rather than ceases braking just when the brake pedal alone is released). Replace both the master cylinder and the brake booster.

Brakes almost gone(car wont stop)- brake pedal super soft ? What's going on?

Driving home today. kinda hot. not too bad . heat was right up the middle of the gauge. about 2 miles from home i notice that when the car feels like the brakes are on when i driving and when i shift gears the car slows down. Kinda like if you drove the car with the e brake on slighty. so a slugish feel. Also i felt like if i was coasting to a stop light in 2nd and took my foot off the brake the car would almost instantly come to a stop with out me using the brake. at this point i made it to the parking garage and noticed that the break pedal felt gummy almost if this sounds right ? the travel on the pedal is a lot farther than usual and the brake's almost would not stop the car. so when pumping the brakes the pedal would slowly come back to where it should be.

after this i parked the car and let it cool down. it was very hot. even the front rims were hot.

You've got one or more calipers/brakes sticking while you are driving. See above. This creates a lot of heat (can start a fire), slows down your performance, and boils your brake fluid. Could be from a failed brake booster, or from a sticking master cylinder, or from aged/clogged/swollen brake lines, or from a caliper/piston issue, etc.

Once your brake fluid boils, you get the gummy pedal or pedal going to the floor without feeling much in the way of braking.

You'll need to correct the calipers/brakes/booster/master/lines that are sticking/failing, plus fill with all new brake fluid and bleed all four corners plus your master cylinder.



Installing Stainless Steel Brake Lines


Use jack-stands for safety and use chock blocks in front and behind your *front* tires because with the rear lifted, you have no parking brake holding a 348. First, loosen the lug bolts on your wheel (right rear in this case), then jack up that side/end of your car, then remove the lug bolts and remove the wheel.

Now put your 11mm brake-line wrench onto the engine side of the brake-line to rubber brake hose connection ...(and you do *not* have to remove the inner fender liners for this job).

Next, put your 17mm brake-line wrench on the underside of the rubber brake line fitting.

Hold both wrenches and loosen the top metal fitting nut with your 11mm wrench. Once disconnected, tape or plug the line, if desired, to minimize brake fluid dripping (no big deal if you don't, though).

Remove your wrenches and grab your channel lock, next.

Clamp your channel lock onto the retaining clip that holds the rubber brake line to the post shown in the pictures here.

Simply pull this retaining clip off of the brake line. The pictures here show the clip.

At this point, half of your rubber brake hose is disconnected.

Place your 9/16" or 14mm brake-line wrench onto the caliper-side of your rubber brake hose and loosen, then remove the whole rubber brake line hose. Old rubber and new stainless steel brake lines are also shown:


Install your new stainless steel brake line with your 11mm and 17mm wrenches, then push the retaining clip onto that connection (in the machined groove), and use your 9/16" or 14mm wrench to install the caliper-side of your new brake line, as well.

Now bleed your brake fluid for this caliper, check for any leaks, correct if any are noticed, and reinstall your wheel (hand tighten your lug bolts). Lower your car and then tighten your lug bolts to spec or as desired.

Repeat for each other wheel.


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How To Remove The 348 Steering Wheel Pictorally (click here)
1. Pull Fuse #8 in the front trunk
2. Use both hands to pull off the center leather section of the 348 steering wheel.
3. Gently disconnect both of the electrical connectors to the center horn button.
4. Dab Liquid Wrench on the base thread area of each of the 6 hex screws in the center of the steering wheel.
5. Unscrew each of the 3mm hex screws.

Momo steering wheel (direct fit, no adapter needed) for 348 This 350mm outer-diameter Momo size is the most "common" (pre-airbag) Ferrari model size and has 6 mounting holes equally-spaced on a 70mm inner bolt circle with a 55mm center hole for your yellow/black prancing horse horn button.

An alternative to the 350mm size would be the 365mm size found on the Testarossa and Mondial models (before the Mondial had power steering, anyway). The larger 365mm size has an interesting advantage in that it makes the 348's manual steering lighter (which owners accustomed to cars with power steering might appreciate on the street), though of course ingress and egress is somewhat more complicated.

Steering Wheel Spacers (about $40) will likewise move the wheel closer to you. By moving the steering wheel closer to you, the steering wheel angle/rake/plane shifts. That shift allows easier ingress/egress to and from your 348 seats. It's counter-intuitive, but bigger drivers need the steering wheel to be *closer* to their chest not only to make it easier to enter into a 348, but also for a more natural, less-tense driving position. The hotlinked Hill Engineering spacer (above) brings your steering wheel 1 inch closer. has a 1 1/4 inch spacer as well as a 2 inch spacer. These are easy, screw on/off non-destructive modifications to your Ferrari 348. From the factory, your steering wheel could be adjusted up or down; these aftermarket spacers let you further adjust the steering wheel closer to your chest, or to return it back to its original position next to your dash (as desired), giving you one more way to personalize your car.

Steering/Light Stalk Switch Repaired 

Creaking sound from steering wheel

My steering started making a noise a few months ago. Steering the car itself was fine, but when I would turn the steering wheel I'd hear a noise.

So I pulled off the steering wheel and sprayed silicon grease on everything that I could reach. Then I lifted the front trunk felt liner and sprayed the steering rack joints that I could see. Ditto for crawling under the dash and spraying the silicon grease on the steering joints that I could see when I looked up.

The noise disappeared.

Part 2

The silicon spray did help a bit but I decided to change the bushings anyway. Ordered the them from Eurospares and did as follows.

1 Removed the carpet in the trunk to get access to the holes for the bushings.

2 Raised the front of the car and removed the front cover plate got get access from underneath the car.

3 Removed the bolts holding the bushings.

4 Removed the old bushings and put new one in. This is a bit tryicky but after fiddling about for a while I managed to get them into place. Access from both sides is neccessarry to get them correctly in to place.

5 Torqued the bolts and tested everything.

6 Put the carpet back in and the cover plate.

Over all the change too me about 1 hour to complete. No more noise :-) thanks, johan6504



348 Steering (clunk/brief dead feel) Resolved (thanks, mdraeger)

My 348 gts suffers the same steering dead ahead feel I've heard other fchaters discuss. Then, gradually, over a period of time a slight clunk over bumps got bad enough to investigate. It appeared to be the passenger side inner tie rod joint. The outer ball joints were fine. So I pulled out the rack and stripped it down. Both rods were fine, the cause was a worn rack bush. It crumbled into several pieces and fell out. I machined a new bush from silicon impregnated industrial nylon. The original was about 8mm wide but I made the new one 25mm wide. I reinstalled the pinion 180 degrees from original and threw the rack back in the car. Result? 1, dead ahead feeling gone. 2, clunking and kick back gone. 3, steering is slightly lighter and just so much nicer to drive. Cost $00.00 + 5 hours having fun with the fcar. I really should have done this months ago.

You can still check the steering rack bushes while it's in the car. Maybe you should check them before you rip it out? Remove the steering rack boot and then see if there is movement in the rack bushes. Give it a firm shake, where the steering rack end screws on. Won't be hard to see if they are worn. can even jack the front up and shake the wheel left to right and see if there is any movement there. Thanks, Pap 348

Did not even hafta remove the rack. Upon inspection everything was fine except the pinion had 15/1000's of end shake. Adjusted the endplay & put her at 3/1000's. She is tight! My mission is now complete. Handles perfectly now. Thanks, chrmer3


Steering Rack Removal/Re-greasing/Rebuilding/Repairing

In the Owners Handbook:
"The steering does not need any particular maintenance. If no leaks are verified, neither a replacement nor a replenishment of the semi-liquid grease is required. If the leaks are verified, the steering gear has to be drained completely from the grease contained in it, whereafter 120cc of the prescribed semi-liquid grease have to be filled up."

The chart says it uses 4 fl.oz. (120cc) of BP Energrease FGL (G 4937). It doesn't show how to drain it or fill it. Thanks, Miltonian

...make sure the problem is not the brake master overflow hose dumping fluid on the rack. I have seen this and it has fooled some people. Thanks, fatbillybob


Rack removal:
1) take pickle fork off tie rod ends
I unthreaded as I intend to re-use old ones.
2) take interior carpet out
only had to pull away from front bulkhead
3) take wheels off
4) unbolt 4 bolts to rack
I also had to remove driver side sway arm bush and bracket and cage bolts and disconnect sway bar from lower A arm in oder move sway bar forward to get necessary clearance for box to clear opening in wheel well.
5) disconnect from the inside helicopter joint on the floor under the brake area
6) slide rack out either wheel well
May need to remove center undertray to gain access to air con hoses that may get hung up on rack mounts. (I did) ...and a new 348 steering rack from Randy at Conti was around $700.00

thanks, hzimmer

Mark 328 points out that Reyes Alternators in Orange, Ca said they could rebuild 348 steering racks for $170.00.
Their number is 714-633-4208. The owners name is Leonardo Reyes.



Starting Point For 348 Power Steering Conversion

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To alleviate common high speed handling issues:

Remove your used tires and install/balance perfectly new tires of the same type and brand, with the factory correct sizes on factory issued wheels. You now own a Ferrari. Stop being cheap.

Insure that your tires are inflated to the correct air pressure (32 lbs to 35 lbs depending on brand/model).

Examine your rear sub-frame (and springs) for cracks/breaks in the frame metal.

Examine your wheel hubs/bearings, especially at the rear. Can you wiggle a wheel when elevated and shaken by hand? Do you hear a noise from the bearings when you hand turn a wheel?

Examine your suspension bushings for wear, undue noise/play, and loose bolts.

If your rear shocks squeak/groan at slow speeds over small bumps, then replace them. Check your disc brakes, including parking brake drums, for any catching.

Install 20mm or 25mm spacers only in the rear of your early model 348. Ideal 348 Wheel spacer Setup (thanks, henkie)

Are you leaking any slick fluids in front of any of your tires?

Check your ride height. Do you have more than 11 cm clearance above the ground to your front bumper?

Have your car aligned (camber and toe-in) by a knowledgeable Ferrari shop.

Now get your car itself weighed/balanced on all four wheels (AKA "corner weighting"). Adjust the individual ride height of each shock and properly balance the car.

For extreme track speeds (e.g. 160+ mph), the 348 SS lip spoiler is recommended. Add it or a larger race version to the bottom of your front bumper.

When set up right, 348's are extremely stable and predictable at high speeds.

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Creaking sound from your 348's suspension? Check for loose pivot bolts at your rubber bushing locations, which can become loose enough over time to add new noises (though typically don't pose a direct safety hazard).

348/355 Bushing Replacement

How To Change Your F348 Shocks *thanks, Rexrcr, No Doubt

Interactive How To Change Your F348 Shocks *thanks, Rexrcr, No Doubt

348 Shock "Re-Valving"

Part #'s for 348 Shocks:

Front - Ferrari Bilstein 141857 (Late Front)
Rear - Ferrari Bilstein
141858 (Late Rear)

Hint: an oily wet, black rubber bushing on top of your shocks typically means that your shocks are going bad and need to be rebuilt.



Front Shocks 146290
Front Springs 151881
Rear Shocks
155188 or 146291 (early rear)
Rear Springs 148786

If you're doing any suspension work, here are some super-high quality items you may want to consider:
141860. Shock, lower ringnut (348, 355, 512TR, 512M).
155086. Shock, upper ringnut; Spring perch (348, 355, 512TR, 512M).

Aftermarket Shocks


How To Remove a 348/355 CV Joint/Axle/half-shaft to Replace a CV Boot

I changed the inner cv boot and thought I would post the results for those who might wish to attempt this repair as it was a little more involved than I thought. The half-shaft/axle end attached to the wheel is splined, with a nut on the end. You will need to remove the rotor to get to it, but that's no biggie.

0) Mark both the inboard and outboard axle positions with relation to the transmission hub & rotor with White-Out
1) loosen 6 bolts on inner cv boot with 13mm 12 point socket and a breaker bar (you can loosen 2 bolts at a time, raise car & rotate wheels and repeat procedure). 348 & 355 CV joint to tranny flange torque=57 ft/lbs
Next (and not before),
2) remove wheel.

2b) Remove the axle/hub nut

2c) Remove caliper. There are two bolts that hold the caliper in place; remove those and then move the caliper out of the way (you should use a coat hanger to hang the caliper so you don't mess up the brake lines), and you may need to hit it with a soft hammer to get it to come loose.

2d) Remove rotor and axle-boot heat shield (355's). Wheel-side pics
3) remove catalytic converter (due to limited clearence with the exhaust manifold in removing the axle later on.... this must certainly be moved out of the way for the 355).

4) remove the top knuckle long bolt (about 9" long and attaches knuckle to the upper a-arm).
5) remove the bolt which attaches the lower shock to the upper knuckle & disconnect the sway bar nut at the upper knuckle.

Note: without disconnecting the 355's knuckle you will not have the clearence to pull the axle out.

6) Pull the knuckle down and out and remove the axle out of the hub bearing & remove the axle.

Thoroughly clean the cv joint with brake cleaner, dry and regrease with cv joint grease and install new boot and plate covers.

There is still a (355) clearance problem with re-installing the axle with the exhaust manifold outlet pipe...which can easily cut the new inner cv rubber boot- one solution is to remove the starter motor- but what I did was wrap the inner cv boot with rubber (used a 10"x12" piece of trailer tire inner tube) and duct tape & gently "rolled" the axle past the "sharp" exhaust manifold outlet.

7) reverse steps 1-6 (line up your Step 0 White-Out marks and replace your hub/axle/central nut with a new duplicate) and you're done. The torque number for the central nut is 250/Nm (25/Kgm). For the caliper bolts they are 64/Nm (6.4/Kgm). For the bolt holding the rotor in place 20/Nm (2Kgm). As for the bolts that hold the CV joint to the trany flange I don't know for sure, but they may be 57 ft/lbs. I just tightend those down as hard as I could by hand. Thanks, cf355

photo by pino of 108mm aero boot installed

A few notes that I would throw in are:
a) remove the airboxes on 355's to allow better access to the CV joint bolts (57 ft/lbs is the proper torque for these bolts)
b) If you have the wheel off, you can still remove/tighten the CV joint bolts by using the screwdriver in the rotor trick.
c) Instead of using the factory inner boots, I was able to use the "aerodynamic race boots" for the 108mm joint. Thanks, pino

Complete Pictorial For 308 CV Boot RnR


How To Remove Center Hub Nut

That detent is the hub nut locking device. You first have to get a small pin punch and tap that out so the nut will then turn. If you dont, you will sit there all day battling away. Thanks, Pap348

Next, soak the axle nut threads with liberal amounts of Liquid Wrench for an hour or so, stick a screwdriver through the one open hole (and/or apply parking brake if connected/working) so that the hub assembly won't turn as you apply force, then use a large breaker bar on your ratchet handle to move that 36mm bad boy (be sure that you are turning/loosening in the correct direction in case some Ferrari hub nuts might have left-handed threads).


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The 348 exhaust has a secondary air injection system. It will come on for few seconds at start up even when warm. It cuts off at 4000 rpm's even when cold. This may make a minute change in exhaust sound. Thanks, DrT348


Early 348 models have two mufflers. Newer 348 models have one muffler.


Water dripping from 348 exhaust muffler tailpipes typically indicates a 348 that is running too rich.


Exhaust Smoke

There are numerous causes of Ferrari exhaust smoke. Two of the main causes, however, are overfilling your oil #1, and valve train damage #2.

The first time 348 owner typically makes the mistake of checking the car's oil level when the engine is not running. This usually gives a false reading of "no oil" on the dipstick because the Ferrari 348 has a race track dry sump oil system (check only when hot/running). Seeing "no oil" on the dipstick, the new owner usually panics...adding quart after quart, liter after liter of oil. Then the new owner starts the car and sees white smoke or gray smoke, thinking that major engine damage was done while there was "no oil" in the car.

In reality, the extra oil that was added probably just needs to be drained or vacuumed out. The air filter and dual MAFs may need to be wiped clean (an overfull condition causes the dry sump system to pump oil back up into the air intake), too. Once the extra oil is removed and the airfilter is wiped clean, the 348 tends to run with no exhaust smoke (and there is seldom any permanent damage done from this overfilling mistake). Welcome to the 348 Brotherhood.


But when new exhaust smoke is accompanied by a metallic engine rattle, then major valve drain damage is the odds-on cause. Should the 348 timing belt stretch or break or lose a tooth or jump a tooth or a cam gear come into contact with some foreign object (even momentarily), the pistons will strike some or all valves. This damage will generally manifest itself with exhaust smoke and a rattle while the engine is running that wasn't there before the damage. Often the engine will still run and the car will still drive, however (not recommended).


Exhaust Popping

Could be a burnt exhaust valve. An easy cheap check if you don't have a compression tester (around $20 or so at parts store) is to disconnect plug wires one by one, til you find the one that stops the exhaust popping when disconnected. BE SURE TO USE INSULATED PLIERS AND GLOVES OR YOU'LL GET A SURPRISE! Alternatively, disconnect the wires to each injector one by one (its a good time to check your injectors anyway-a bad injector will cause a lean condition in that cylinder, thus extra heat= burnt valves). Unburnt fuel getting by an exhaust valve at compression may burn in the exhaust (pop), yielding ugly black soot out of your exhaust pipes. *Thanks, Plugzit


Exhaust Ticking or Tapping Noise

This is normally a 355 issue. The ticking begins when you start the car, then goes away as the engine warms up...but over time becomes louder. The most common cause is header failure (e.g. cracks, holes burned through). 348 headers may be able to be welded for less than $75 to fix a single crack or hole...355 headers typically need full replacement on one (most often the right) side. This company, JPExhausts, will hand make your replacement 348/355 headers for $700 per side such that all factory connections/covers can be re-used for a fully "stock" appearance. NitrousFerrari says "they mandrel bend higher gauge steel to last a lot longer and use your original flanges, they charged £350 + vat per side, they did a superb job, but obviously shipping is going to be the issue for you..." Other (but more expensive) aftermarket and OEM solutions exist (NAPerformance for $3,300; QV London for $2k per pair, OEM for $2,500 each side, Tubi, Nick's Forza, Fiorano, Metalcraft, Larini (reconditioning), etc.) if you don't want to deal with international shipping based on your location.

"I think Ferrari used too thin a wall thickness instead of 16 ga or better and not the right alloy S.S. . It looks and welds like 304. But 321 or heaven forbid the pricey Inconel would have been the better choice. The aluminum heat shielding is as much the culprit too as it holds the heat in to protect the car and still gets so hot it melts the drive axle boots even though they are shielded too. If I owned a 355, I'd cut the shielding off right off the bat, and have them ceramic coated inside and outside as preventive maintenance. This will extend the life of the header and reduce engine bay temperatures as much as 60%. It seems that even Thermotec header wrap is better than the aluminum boxes stuffed with glass that hold water and don't help in that respect as well." Thanks, Speedmoore

"The cost [for welding a simple exhaust patch rather than buying all-new headers] is obviously pennies when you are a guy like me or a few bucks if you have any mechanical skill at all to remove only 8 nuts per side or a couple hundred bucks if you are totally clueless but can fill a gas tank yourself. Also, you would be suprised at how long some questionable patches can hold when a good TIG welder is used and the welder has some skills. If you want to get fancy you could even exterior sleeve high heat points in a header such as the immediate exhaust port or a bend and even that is cheaper than a new header." ... "Why buy new headers when a welder can weld up the hole for about 15 bucks? Just find a good welder who TIG welds aluminum. A guy who does aluminum can do stainless all day long in his sleep. Heck if you send me your header I'll weld them for free you just pay for shipping to and fro. I'm not a pro but I have welded many a Ferrari exhaust system." Thanks, FatBillyBob

They crack around the AIR tubes...the actual piping indeed does melt. In fact the majority of them melt as in the pic above, before they crack. Every single manifold I have replaced, I cut the shielding off and each and everytime they have melted in the same approximate place. Thanks, tbakowsky

(picture thanks to Mondial86)

355 Exhaust Tapping Noise


Sound From Collapsed Catalytic Converter

My 348 GTC started to exhibit a strange problem today. I had a tiny bit of trouble starting it on the key, and when it started it ran a bit rough with an odd clanking type sound. When I was driving along the motorway (freeway) today it sounded like something came loose and dropped off (!) the car but I couldn't see anything in the rear view mirror.

When I tried to start the car from hot, I noticed what seems like an offbeat sound to the exhaust and the odd occasional clank/rattle from the engine area. On closer inspection the sound appears louder from under the car. I used a pipe for a stethoscope and some of the sound appeared to be coming from the diff casing, but to be honest I reckon it's a cat breaking up. If I tap the right hand cat with the pipe it seemed to increase the frequency of the noise.

When I got home, the noise was still there but the car seemed to run fine, the only difference I noted was a slightly higer idle. No slow down lights or anything like that.

Yep, collapsed Cat on one side. Thanks, Lagerlout



Exhaust Design


Dripping water from your exhaust when your motor is cold? Water vapor is a natural chemical byproduct (one of many) of gasoline/oxygen combustion. Cold exhaust pipes can cause that natural water vapor in your exhaust to condesate into liquid form (i.e. dripping out of your exhaust pipes). This happens most in cold climates when your air/fuel mixture ratio is at its perfect stoichiometric ratio (great for gas mileage, but not ideal for full power so you only want this to occur at idle or very low rpms).

348's have correctly-engineered rear bumpers with cut-outs below our exhaust pipes. This prevents the exhaust water stains that are found on later model Ferraris (the easy solution for those newer cars is to extend your tail pipe tips past your rear bumper).

Exhaust Design 2

Thought this may be interesting to a wider audience than the several thread this came from. The calculation examples we will use are based on a 320 hp 3.2 liter normally aspirated engine.

Base facts and Assumptions:
Required flow capacity is about 2.2 CFM (@1.5") per hp
A straight pipe will flow average about 115 CFM/sqin area
Areas of common exhaust pipe:
2" = 3.1 sqin
2.25" = 3.97 sqin
2.5" = 4.91 sqin
3" = 7.0 sqin

So, for our 320 hp V-8 engine,
Flow required " 320 x 2.2 = 704 cfm total, or 352 CFM per side for that side's 160 hp.

1. Headers.

The important things are the length prior to the collector, and the collector characteristics. Some say the individual lengths do not have to be equal, some do.

Requirements for flow In out engine, each cylinder makes 40 hp per cylinder, requiring 88 CFM per cylinder (40 x 2.2) - so header primary tube diameter required is 0.8 sqinch, or about a 0.78 inch pipe. The final collector on each side the volume must increase over the tube diameter to generate the scavenger wave and carry the combined flow volume, so it must exceed 352/115, or about 3 sqin - so a 2.25" pipe is good on each side in our example, and is in fact about what Ferrari uses.

The famous mismatch in header/ exhaust system lengths from front to back on the transverse V-8s is actually deliberate - it will spread a the torque and powwer curve widely through averaging. Exactly matched lengths will give you a higher final number, but it will be more peaky and narrow. Again, the Ferrari stock system gives a wide power band.

Similarly, in racing engines all four collecting tubes generally drop into one collector before the exhaust also give the maximal power, but at the expense of a comparatively peaky power band. Ferrari uses the "Tri-Y" design, or a 4 into two into one design which again is best at delivering a wide flat torque and power band for a street driven car.

Ceramic coating gives excellent heat insulative properties to the header, which keeps heat in with high gas velocity and lower underhood temperatures. There are several types of ceramic coating available.

Since the Ferrari has a flat crank V-8 w/ even firing banks , no crossover tube is neccesary between sides = that's the beauty of it - each side is already balanced and responds well to a true dual exhaust

2. Exhaust system

Most folks say that as long as it flows enough CFM, the exhaust aft of the collector is primarily responsible for tone quality and not so much hp increases. There are two primary types, acoustic boxes with noise cancellation chambers and absorptive with usually glass packing. Each has pros and cons, but I like the lower deeper tone of the absorptive mufflers, they are readily available and inexpensive.

The greater volume of the absorptive muffler, the lower the sound and deeper the tone. Does not matter if round or oval - the volume is the thing

One of the major determining factors is just what space constraints exist under the car - for transverse V-8s the room is VERY restrictive; for example, the room available in the Mondial 3.2 is a transvese area 35"w x18"l x 10"h. In the transverse engined cars, the lack or room and orientation of the engine is the largest challence to exhaust design - there's just not a lot of room to silence without adding flow restriction (which also can cancel noise).

According to separate textbooks and the thread discussion on dual resonance noise cancellation I've read, two mufflers of equal volume will provide more noise cancellation than one muffler of twice the volume of one small muffler, i.e, it is a non-linear relationship.

A cat acts as a muffler/silencer to some degree

Bends and flow direction changes should be kept to a minimum and use the largest available center line radius (e.g. 1.5 times tubing radius) . If a tighter bend is unavoidable, try to use more than adequate width of tubing to reduce the flow resistance.

In contrast to the headers, the primary advantage of ceramic coating of muffler systems is keeping external temps down and muffler protection.

According to Arvin Meritor engineers and BMW, to meet current legal sound silencing requirements, an absorptive muffler must have a volume equal to 12X the swept area of the engine. This sugests why many 3.0 and 3.2 liter V-12 Ferraris have at least two 14" mufflers per side.

You can "cheat" a little bit by flowing one side through double pipes through a muffler where the sound "sees" two volumes.

Exhaust tips have a large impact on final sound, with resonated tips making a large impact in smoothing the final tone. Older V-12s which also used the doule pipes per side all had singlr resonators at the end of each pipe

So, taking everything in consideration, for our 3.2 liter 320 hp engine (let's just say it's in a Mondial) driven on the street have :

1. ) s/s ceramic coated headers of at least .8 - 1" tubing diameter in Tri-Y design (e.g. Tubistyle Euro header)
2.) mounting flanges port - matched
3.) collectors opening into a single 2.5 pipe leading to the exhaust
4.) Two Dual flow mufflers per side (total of 4) maximizing silencing and tonal smoothing per length in a confined mounting space
5.) Dual resonated exhaust tips; final sound character can be tuned by differnt spec resonated/non-resonated tips.
6. To allow better fit, more silencing capability, less flow obstruction, use reduced tubing radii, going to twin 2.25 inch tubing for each side after splitting from the 2,5" single from the collector
Thanks, snj5!



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Repair Tips For Fixing "Sticky" or "Gummy" or "Melting" Plastic Air Vents

You can use Goof Off 2 from Lowe's

Dr.T348 recommends Easy Off oven cleaner for cleaning/fixing the 348 and 355 sticky vents


Repairing Paint Chips and Paint Swirls

1 - Get touch up paint from and 'blob' remover from Total cost around $100 and will be enough for about 500 stone chip touch ups. The Langka product is a selective thinner that removes to paint blob so that the surface of the paint is flush after the touch up. You do not use the clear coat on the red Ferrari (it is a single coat paint).

2 - Get the Zaino brothers polish kit (z-8, Z-5, Z-2, FX accellerant, clay bars, and polish applicators (about $85). It will take you about a full day to do the entire process, but the finish will absolutely look show car quality. I have done it on my 348 and can't believe how the swirls go away. *thanks, bt348pbg


Do not use Ammonia if you have any after market tint...

Use a quality window cleaner, the best I have found over the counter are Meguiars NXT and Stoners' IG.

Use a microfiber towel..

Spray window with cleaner, wipe with microfiber until streaky, turn over and wipe clean.

If you get streaks after this, then the problem is with the microfiber. Many people wash their microfibers incorrectly (if you use fabric softner in your laundry loads, it will contaminate your fibers, even if you don't add it to the cycle with the microfibers). This will cause nasty streaking as it is the residue from the fabric softner (which is usually made with some type of animal fat).

A clean microfiber (that has been washed correctly) will pull any streaking agents (grease, grime) off the surface of the window very easily.

Also, if you choose to go the paper towel route, do not use any "desginer" paper towels as the ink used to dye towels can cause streaking, use plain old white ones.

Newpaper works fine as well (though messier IMO) because the ink in the newpaper print acts as a fine abrasive to deep clean the window.

There are many routes to New Orleans so to speak, the best I have found is microfibers and a quality glass cleaner.

Don't use ammonia (windex) based cleaners if you have tinted windows as it will dry and lift the film overtime. - thanks,


Recovering Your 355 (or 348) Leather Dash

Leather and Alcantara supplies for your interior


348 Carpet Sets:; also Aldens Auto Trim and Upholstery in Louisiana (pre-Katrina/Rita)

Custom Gauge Face Plates

Ferrari Gauge Faces 

Modified 348's:

 *SPORTS CAR INTERNATIONAL July 1991 - Zagato 348 Cockpit View


Upgrading Side Marker Lights To Flash When Signaling (thanks to Mike328)

Updating Your Green A/C & Fan & Heater & Clock Displays To Amber Lights On Red Background

Console and Dash Removal

(it's just 2 phillips screws at the bottom corners for the dash instrument pod/cluster)

 *rear instrument pod view thanks to Miltonian

(and it's just 4 phillips screws for the console) *thanks, Rayman

348 Car Keys: Just about every hardware store in the U.S. carries the Silca and Ilco "X152 FT46" key blank. Cost? About $2. These blanks can be cut by the hardware store and will operate your 348 door locks and ignition. The Ilco fits Fiats and Ferraris alike. The better looking rubber headed versions cost about $8 here.


A/C & Heater Fan Vent Removal:

 *Picture thanks to Miltonian

Each side vent has one retaining clip that needs to be pulled down, typically with a flat-blade screwdriver. The center vent has two such retaining clips that must be pulled down simultaneously.

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How To Read Spark Plugs


348 Performance Upgrades

Gutted OEM Cats Vs Straight Pipes

Ultimate 348 Suspension Setup For Track/Street (Thanks again to Dr. Carl and others!)

"the most aggressive 348 set-up I can do with full Pirelli slicks which can magnify suspension problems. I drive the track only and have solid delrin bushings, challenge suspension setting, revalved shocks and springs and huge brake ducts. Let me tell you this car handles and yours can too. Additionally, when the suspension is right you can threshold brake this car all day long with confidence in a straight line with no pitching. If you want to make your car handle better start with the basics and make sure your shocks are good and bushings are good and the alignment/chassis rake is good, and a corner weight balance is an easy luxury to afford too. Then let us know if you have a smile on your face."

To upgrade an F40's suspension, use the 348 Challenge bushings (interchangeable between both models as well as between all 348 variants). *thanks rexrcr

Likewise, the F40 and 348 Competizione share the same half-shaft axles.

"384s and 355s has two suspension issues that a driver should become aware: 1) if the front end is too low, there is instability under braking and at the moment of steering input; 2) the rear end is setup so that after you start to add power while turning you are NOT ALLOWED to remove power.

1) When the front end is too low (on stock springs and shocks) the front tires have more grip until the car gets fairly large cornering loads transferred to the outside tires. This gives the car quick turn in, and can cause spins under brakes or non-judicious use of the steering wheel.

2) At the rear, the ride height can be used to adjust the oversteer/understeer relationship. When the rear end is too high OR the rear tires have too small a rolling radius oversteer is the result. These cars have adjustable spring perches, if you are having a handling problem that takes more than 2 PSI of tire pressure change to balance it out, then get the car aligned with a set of scales (corner weighting) AFTER adjusting the ride heights back to factory specs. After this, you can dial in the oversteer/understeer relationship you want with 1 or 2 turns of the spring perch collars; UP give oversteer, down gives understeer." Thanks, Mitch Alsup

"348's respond very well to shifting the roll couple distribution forward, and disconnecting the rear ARB is one way to do it, though not nearly the best. It was the easiest way to cheat in Challenge and probably not get caught." - thanks, rexrcr

Creaking sound from your 348's suspension? Check for loose pivot bolts at your rubber bushing locations, which can become loose enough over time to add new noises (though typically don't pose a direct safety hazard).

Upgrading 348's to F355 Adjustable Shocks (thanks, plugzit)

Do It Yourself 348 Racing Bushings (thanks Dr. Carl, rexrcr, Mitch Alsup, 348Paul)


348 / F355 Coil On Plug MSD Conversion (thanks, JeffDavison)


348 Emissions - How To Legally Pass Your Emissions Test (thanks, No Doubt)

 *Bosch Graph


Max performance is generally accepted to come from an Air Fuel ratio (A/F) of between 12.7 and 13.2 to 1. Max economy is generally believed to come from an A/F of 14.5 to 14.7 to 1.

Changes to your car that affect either airflow or fuel into your cylinders will affect your A/F ratio. This can be good. It could also be bad. A/F ratios less than 12.7 or greater than 14.7 are going to be wasting fuel, losing power, both, or worse.

So if you are enhancing your 348's performance, then you are going to be testing your A/F ratio. The closer your A/F ratio to 12.7 to 1 at Wide Open Throttle, the better "tuned" your car...with one caveat: A/F ratios closer to 13.5 to 1 let 348's rev up faster. So an ideal A/F curve would be 13.5 to 1 at partial throttle, gradually getting richer (i.e. 12.7 to 1) as your RPM's and throttle position increase to redline.

Your 348's ECU chips have on-board fuel-mapping that should be designed to keep a reasonably consistent A/F ratio throughout your entire RPM range from idle to red line. The proper A/F ratio requires good O2 sensors, by the way (to provide the right feedback to the A/F ECU's).

Aftermarket (or, gasp, lust, 348 Competizione) ECU chips tend to go for that 12.7 to 1 (sometimes as rich as 12.5:1) ratio more aggressively and more accurately, however, unless your ECU chips are hand tuned for your 348's specific system (age, quality, existing modifications, local weather and barometric pressure, etc.), then such chips could be worthless or even counter-productive. Then again, they might get you just the A/F ratio that you are lusting for. It all depends. YMMV.

Adjusting your fuel pressure can raise or lower the average A/F ratio delivered by your ECU chips, whether those chips are stock factory or aftermarket. So if your stock ECU chips are holding a steady A/F ratio, then all you'll need to do is to adjust your fuel pressure as you add or remove various components to or from your car.

If your stock ECU chips do not hold a steady A/F ratio over your full RPM range at Wide Open Throttle (WOT), then you'll probably want some better ECU chips. Aftermarket chips often advance your timing for more complete A/F mixture burn, too.
Powerchips ECU Chips Dyno Test

If you can obtain an A/F ratio curve of 13.5:1 from idle to 12.5:1 red line, then you have a "tuned" engine.

You can increase your air flow to your 348 in a variety of ways, many of which are inexpensive or even free of direct cost (though seldom free of mechanical or personal risk).

The gaskets between your intake plenum and intake runners, for instance, can be "squeezed" (even at the Ferrari factory during assembly) so that small parts of the rubber intrude into what should be a wide open, free-flowing area for your air intake. Cutting out that excess rubber, or using special gaskets that don't get "squeezed" will give you an increase in air flow (note: any such increase in air flow changes your final A/F ratio, requiring the adjustment of your fuel delivery via fuel mixture or other means).

The same situation can also exist with the gaskets between your 348's two throttle bodies and your intake plenum.

Likewise, your four protective wire mesh screens on the front and back of your Mass Air Flow (MAF) Sensors can be removed to increase your air flow (at the expense of additional mechanical risk, at the very lest).

Your 348's large air filter can be upgraded to many of the newer cloth-style filters such as HKS or K&N, etc. K&N has two part numbers that are valid (they simply changed numbering systems) for 348's:
33-2656 ( KN348 (

Your two throttle bodies can be bored out to a larger size, too (and the intake plenum behind these throttle bodies can be smoothed out or ported for further increases in air flow). Your air filter box can be enlarged or supplanted by a dual air filter "straight through" style setup.

Euro exhaust cam timing specifications are optionally allowed in the US for the 348 Challenge. If you're dropping the engine for a major service, then that's the time to do this modification. It's worth some top end power and nice idle rumble, too. The only cost is time and new belt. You just re-index your 348 cam pulley as they are all ALREADY built to do so from the factory.

More expensive options such as turbo-chargers, different cams, bored out engine cylinders, et al can further increase air flow.

Parasitic Drag:

Reducing engine drag...increases your available torque...which gives you more available horsepower at each RPM speed.

Air flow can be increased into your 348's engine by moving to high-flow, back-pressure-reducing catalytic converters (or going to open "track" pipes) such as Hyper-Flow cats (which flow 30% better than stock Ferrari cats)...a move that will also reduce the parasitic drag on your engine. Ditto again for going to a more efficient (often louder) muffler...or no muffler at all.

Removing your A/C or alternator belt would similarly trade convenience for a loss of parasitic engine drag (translating to more horsepower). Ditto for moving to different sized pulleys for those components, though not in quite such a dramatic way.

Some aftermarket or hand-built (or ported) water-pumps can likewise reduce your 348's parasitic drag from a very large consumer of non-forward-motion power.

Some fluids (e.g. Royal Purple, Red Line, ZMax) may also reduce the parasitic drag in your transmission and engine.

Lighter-weight internal engine parts (e.g. crank, pistons, etc.) can reduce parasitic engine drag, too.

Better spark plugs (e.g. NGK Iridium or Splitfire Platinum) can increase your engine's efficiency by burning more A/F in each cycle. NGK Iridium model DR8EIX is the best of the NGK plugs for the 348. Best prices found so far are from: and .

Likewise, hotter sparks from an MSD/Coil On Plug conversion can give you a more complete A/F burn that yields more power, better emissions, better revving, and better idle.

The larger the gap (up to a point) in your plugs (even your stock factory plugs), the hotter your spark, which burns more A/F in each cycle. You can freely bump up your stock factory plugs in your 348 to .028 inch, per our Owner's Handbook.

I'm running .0285 inch gaps in my Splitfire Platinum plugs, but what you can get away with gap-wise here is limited and will be different for every car in every location. Your altitude above sea-level will affect this equation, as will your level of smog and your true octane in your gasoline, among other things. A smaller gap will reduce the frequency of misses (but also reduces the A/F burn efficiency itself in the meantime).

If you get either pinging or (gasp) detonation anywhere in your RPM range from idle to red line, then you've gapped your spark plugs too wide for the Advance set in your timing and/or for the octane of your fuel. Ditto for "misses."

Adding octane booster may be a simple way to cure light pinging (if the only change to the car that you made prior to the pinging was to gap your plugs wider), as can increasing your fuel pressure (see what happens in that case above when you change your A/F equation, though) or enriching your mixture, so can retarding your timing advance. Technically, decreasing your airflow or lowering your compression ratio could also achieve that same result, though those particular solutions would tend to run contrary to *adding* power to our 348's!

Intake additives such as NO2 gas can also enhance the performance of our 348's (though again at additional mechanical and personal risk).

You can increase your fuel flow by
adjusting your A/F mixture, raising your fuel pressure, and/or switching to larger fuel injectors. In some cases this will require better fuel pumps.

In general, the cooler your fuel and air going into your engine, the more power you'll get out of your 348. One "secret" hot-rodder trick is to insulate your air intake plenum from the heat of the engine block by inserting a thin
Peek thermoplastic (best) or nylon/phenolin spacer in between those two components.

 *Swift nylon spacer shown thanks to Jardamuth of TeamSwift.Net

Your fuel and air can be directly cooled with aftermarket CO2 systems. Street racers will often place rubber or plastic ice packs around air intake and fuel lines just before a run, too.

Keeping your engine oil cool (i.e. operating temperature, but not above 250F) will help. Besides keeping your oil cooling radiator fins clean, you may want to add a heat sink around your oil filter. Different types and brands of oil itself will also make a difference in temperature. For instance, Red Line's special synthetic 5W-30 will run about 5 degrees cooler as well as reduce your engine friction to place more torque/horsepower on the ground at your rear wheels, compared to a thicker oil such as Shell 10W-40 which would give you added engine protection for extended track racing (but at the cost of a few friction horsepower as well as increased engine wear at startup).

Likewise, keeping your water temperature down will aid in keeping your oil temperature in a more reasonable range. Flush and fill your radiator on a regular basis. Keep a magnesium anode grounded to your radiator fill tank to delay electrolysis, and add a quality temperature reducer such as 40 Below or Red Line's Water Wetter (oh, and keep those radiator fins clean!). You *could* go to a lower temperature thermostat, too (though that will delay your engine getting your oil into its initial operating range).

You can improve the shifting on your 348. The faster and smoother that you can shift, the more power you'll be able to deliver to your wheels in any sprint.

Many options abound. I use Red Line's Superlight Shock Proof synthetic gear oil. A slickshift gate on top of the above modifications will enable you to further shift faster and more smoothly by reducing the gated metal areas where your gearshift lever can be stopped or delayed during travel between gears. Apply grease to your shift gate inner edges and outer gearshift shaft, too.

The old rule of thumb is that each 100 pounds of weight gained or lost makes a point 1 (one tenth, 0.1) second difference in your 0 to 60 times. The less weight, the higher your power to weight ratio, the better.

Lightweight Speedline wheels can make a difference, as can carbon fiber replacement parts. Stock 348 seats are perhaps some of the most needlessly heavy seats ever placed into a performance car. Lightweight Ferrari Kevlar seats are available as direct replacements, saving scores of pounds of dead weight. Aftermarket sports and race seats are likewise available, and even Corvette seats from the 1990's will save considerable weight (though they will require two new bolt holes to be drilled so that the Ferrari seat tracks will work on them). Keep in mind that your lap belt and receiving lock will need to be moved from the bottom of your stock Ferrari 348 seats to your aftermarket or Corvette seats if you go with one of those options instead of the Ferrari Kevlar. Your 348's shoulder belt, however, will still lock into your mouse motor receiving matter which seat you prefer.

At the very least, switching the location of your stock Ferrari driver and passenger seats will give you many additional years of "like new" seats by changing the wear patterns on your leather.

Our 348 manual lists a Bridgestone and a Pirelli street tire. The Bridgestone should have 36 pounds of pressure cold in front and 34 pounds cold in the rear. Your Pirelli should require 33 pounds cold on all four. Nitrogen is preferable to air.

Perhaps the most dangerous (mechanically) performance modification is advancing your timing past factory specs. The general theory is that firing your spark plugs earlier gives you a better A/F burn (see the above note on spark plug gapping).

That's a great theory, but going just a little bit too far on your advance can blow your engine via catastrophic detonation vibrations. Custom ECU chips that advance your ignition timing MUST therefor ALWAYS be matched with high octane fuel.

In fact, the hotter your spark (i.e. larger spark plug gaps), the less Advance you will want. Technically, your timing advance is the amount of time prior to your piston reaching top dead center when your spark plug fires. Engines fire their spark plugs early, i.e. prior to the piston reaching top dead center, in order to give your air-fuel mixture time to fully ignite...however, by firing early, your explosion in each cylinder is actually pushing down, initially, on your piston...while your piston is still on its up-swing. That works against you. Your piston has to continue to travel up to its summit (against that explosion) before it can start down on its power-stroke. The more your timing is Advanced, the more time your air-fuel mixture has to fully ignite, BUT that also means that you are channeling more energy into working against your upward-traveling piston, thereby adding drag and losing efficiency and increasing internal engine stress. A hotter spark plug, however, requires less time to fully ignite your fuel air mixture, so you need less timing Advance.

Horsepower is your engine's torque times your engine's RPM. So long as you retain most or all of your torque, then the higher your RPM's, the more horsepower you get out of your engine. Raising your red line can often give you more horsepower (in exchange for added mechanical risk, of course).

Likewise, raising your torque via higher compression, better burn (e.g. spark design, spark gap, timing advance), and/or reduced parasitic drag will also raise your horsepower at any given RPM speed.

Better tire compounds and better tread contact (wider wheels/tires, tread design, etc.) will further aid in putting your engine's horsepower to good use.


Speed Tec is a gasoline additive which significantly improves the acceleration of the vehicle. The novel components of the gasoline additive accelerate the spread of the core flame during the ignition process. This is **NOT** an octane booster. Speed Tec makes the combustion more compact, more violent, and more productive. A greater burst of energy is therefore released by the active combustion in a shorter time. At the end of combustion, unburned fuel residues stay behind even with the most state-of-the-art engines. With Speed Tec, the proportion is smaller, i.e. the power utilization per fuel unit is higher. The special composition of the additive also reduces running noise and cleans and maintains the inlet system.

Instruction: Speed Tec is suitable for all 4-stroke engines. One 250 ml can is sufficient for 70 liters of fuel. And the effect will last 3/4 full tank. Pricing will be $30

The American Version: oxytane

  The Man Who Stumped The Chump


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1. 1994 Ferrari 348 Spider

NHTSA Recall ID Number: 98V250000

Recall Date: OCT 09, 1998
Potential Units Affected: 556

Make : FERRARI Model : 348 Years : 1989,1990 Build Dates : 19890701 - 19901201 NHTSA CAMPAIGN ID Number : 92V071000 Date Owner's Notified: 19920629 Date Received by ODI: 19920518 Date Added to Database: 19920529 Manufacturer's Involved: FERRARI NORTH AMERICA Manufacturer's Responsible for the Recall: FERRARI NORTH AMERICA INC Manufacturer Campaign Number: Component: FUEL SYSTEM, GASOLINE:FUEL INJECTION SYSTEM Potential Number Of Units Affected : 812 Summary:

Make : FERRARI Model : 348 Years : 1990, 1991 Build Dates : 19890701 - 19910101 NHTSA CAMPAIGN ID Number : 92V072000 Date Owner's Notified: 19920629 Date Received by ODI: 19920518 Date Added to Database: 19920529 Manufacturer's Involved: FERRARI NORTH AMERICA Manufacturer's Responsible for the Recall: FERRARI NORTH AMERICA INC Manufacturer Campaign Number: Component: STEERING:WHEEL AND HANDLE BAR Potential Number Of Units Affected : 645 Summary:



Regulation Part Number: Federal Motor Vehicle Safety Standard Number: Notes:


Technical Service Bulletins (TSB's)

Parts for above TSB:

144713 -> 171177
149241 -> 185343

148672 -> 174249
172429 RING (174249+148671 REPLC BY 183581); 183581 is the currently spec'd rear main seal.

Thanks, Jack Russell Racing



348 Production Numbers (thanks, Christian.Fr):

300 htp
348 TB built 2894 ex. (s/n 81617-96679)
348TS built 4228 ex. (s/n 81651-96964)

in1993 La 348 Spider. Engine 320 hp (312 U.S.)
La 348 Spider built 1090 ex. (s/n 94504-99947)

in 1993 Ferrari 348GTB et GTS.
348GTB built 222 ex. (s/n 96655-99697)
348GTS built 218 ex. (s/n 96824-99197)

56 348 Competizione (s/n 96064-99143) 360 to 550 hp
and 80 348Series Speciale for USA (s/n 92812-95820)


Birmingham:World Class Auto Repair (Alan and Phillip raced their Ferrari Daytona and other F-cars) 4710 5th Ave S. 205-591-7990 ($72.50 per hour shop labor rate for experienced Ferrari techs, no waiting to get your car in, either).

Hesco (Lee Hurley is one of the top ranked NASCAR tuners)

Huntsville: International Motors (owner Mike Gettemy is an ex race mechanic who knows Ferraris quite well) 256-316-6141.

Maryland: DiFatta Brothers on Bel Air Rd.

North Carolina:

California: Brian Crall Service, San Ramon, CA: 925-552-9700

Southern California: EUGENIO'S FERRARI SERVICE (626) 484-7933

Colorado: Dave Helms has his own service center up and running in Boulder. His # is 303-938-9000

North East: Wide World of Cars (WWoC)

Great Ferrari Shop Testimonial

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ECU Codes

How To Check The 348 A/F ECU Diagnostic Codes (non-Euro 348's):

Thanks, ernie

Remove the cover(s) behind the seats so that you have access to the ECU's.

2) Place the key in the ignition and turn it to the (on) position, but do not start the car. You will see the two Check Engine Lights (CELs) on the instrument panel illuminated (if not, then you've got burned out or missing dash bulbs*** and can't proceed until new bulbs/LEDs are in place).

#2a) Make sure that the transmission is not in gear. Now start the engine, and let the car idle. Wait for all the dashboard warning lights to turn off, then follow the rest of the procedure for pulling the codes.

3) Push and hold down the button** (located next to each ECU) for 5 seconds, then release it. When you are holding down the button for those 5 seconds you now should see the dashboard check engine light illuminate for the ECU you are on (check engine light 1/4 or CEL 5/8 depending upon which ECU button you are depressing).

**Oh, you don't have a red button?! Not all 348 models have them. You'll need to order two parts: tester cable 146196 and button 145810 thanks, stevew

***Oh, you've got a Euro 348 that doesn't have CEL's?! You'll need to add two bulbs under your instrument gauge console (two phillips screws to remove). This will give you the U.S. model electronic engine diagnosis functionality.

4) When you let go of the button you will see a pause and then a long flash for 2 and 1/2 seconds, a pause with no flash for 2 and 1/2 seconds, then begin the flashes of the engine codes. The long flash indicates the beginning and end of the code. Then it repeats the same code, until you move on to the next code.

5) Each number of the code is flashed for 1/2 second followed by a pause and then the next number in the codes is flashed. For example you will get the long flash indicating that the code will start, a pause, three flashes, pause, two flashes, pause, one flash, pause, four flashes, pause, a long flash indicating the code is finished. If this were the series of short flashes you got, the code would be 3214.

6) After you pull a code you will notice that it just keeps repeating. To get to the next code what you want to do is wait until the long flash comes on after the code. When the long flash comes on you want to hold down the ECU button for the whole flash and let go of it in the middle of the pause. You should then see the check engine light give you another long flash to indicate the beginning of the next code.

7) When the last codes has been pulled, you will get nothing but long flashes telling you that there are no more stored codes.

8) Now that all the codes have been pulled you will want to clear the ECU of the stored codes. When the ECU's is giving nothing but long flashes, you need to push and hold down the ECU button for 10 seconds to clear out the old codes.

9) If needed, repeat the process for the other A/F ECU (348's have two).

10) The A/F ECU Codes are explained below.

NOTE: contrary to a long-standing myth, 348's do *not* store the above trouble codes after the battery has been disconnected. 348's have a battery disconnect switch above the car battery to quickly disconnect the battery.

Also: Euro cars *can* check these codes, however, this may require a Ferrari tool.

NOTE 2: Our 348's store two types of errors, transient and permanent. If your CEL went out, you had a transient code. The error was recorded, but your system hasn't seen it again. The "permanent" codes will remain stored in ECU memory for 50 starts/starts of your car, even if you fix the problem (unless you clear the codes manually or disconnect the battery).

Ferrari 348 A/F ECU Codes (check with engine running):

*note: Your CEL 1-4 light is located on the bottom *right* side of your instrument cluster; CEL 5-8 warning light is to the *left* side of that CEL 1-4 light.

This is because your engine's 1-4 cylinders are on the right side of your 348, and your 5-8 cylinders are on your left side. Likewise, your right side A/F ECU is behind the right seat for your 1-4 right-side cylinders, whereas your 5-8 A/F ECU is behind your left seat. - thanks, AirBarton

Hot wire air flow meter 1111
Engine coolant temp sensor 1112
Throttle potentiometer 1113
Lambda sensor (
O2 Sensor typically unplugged or bad ground or bad sensor) 1114

RPM sensor 1121 (this code may be shown if checked when your engine is off)

Battery voltage 1122
Secondary air solenoid valve relay 1123
Purge valve 1124
(the purge valves are marked as part #21 in this diagram)

Lambda regulation Additive value for self adaptation (O2 sensor or coolant temperature sensor or MAF) 1211
Lambda regulation multiplicative value for self adaptation 1212
Lambda regulation intake manifold compensation (
MAF or O2?) 1212 (1213?)

*Lambda codes 1211 and 1212 refer to the fact that the emissions O2 sensors are going full tilt to regulate fuel mixture and it's still not enough. I would unplug them and run the car to add to the data base. If the car then runs normally then something in the O2 system needs to be considered. If on the other hand if it persists we can consider the code a sympathetic action.
It could also be a problem with the coolant temp sensors. Way too many times I have seen a broken wire at that connector cause similar symptoms and it would also cause a Lambda regulation code.
An open connection or high resistance at the coolant temp sensor will make the A/F mixture very rich. Something it can tolerate when cold but less so when you get some temperature in the motor. *thanks, rifledriver

If the 1211 code appears on one side of your engine only, then you'll want to swap MAF's from your left engine side to your right engine side (this is also a good time to clean your MAFs by spraying starter fluid into each end of each MAF) and vice-versa. When you next drive your 348, notice if your 1211 code either returns on the same side of your engine (if so, then your problem is not MAF related) or if it switches sides to follow where you moved your MAF in the above side-to-side swap (which may very well hint that the MAF itself is the problem).

If the1211 problem isn't MAF related per the above test, then swap O2 sensors from side to side when/if your code returns to see if the issue is related to a failing O2 sensor. See also: O2

If your 1211 problem isn't MAF sensor or O2 sensor related, then replace your coolant temp sensors. If this doesn't solve your 1211 issue, then you probably have a fundamental fuel mixture problem caused by any number of things such as a failing spark plug, bad spark plug wire, bad coil, failing alternator, failing fuel pressure regulator, failing fuel pump or bad fuel pump relay, cams mis-timed, etc.

Short circuit on engine
idle regulator 1311
Open circuit on engine
idle regulator 1312

Electronic control unit 1313 (can be triggered by something as simple as your main Ground strap from frame to tranny being bad or disconnected)

Injection valve 1 (or 5) 1411

Injection valve 4 (or 8) 1412
Injection valve 2 (or 6) 1413
Injection valve 3 (or 7) 1414

Malfunction Indicator Lights (MIL) 1444 *dash light burned out

The 8 undocumented error codes:

2123 Secondary air solenoid valve

Valve (or relay for an oil or water cooling fan) 4111
Stroke sensor (phase sensor) 4112
Power module not used 4113

TDC control unit recognition 4114 (this code may be shown if checked when your engine is off)

Catalyzer temp ECU 4121
Catalyzer temp too high 4122
Speedometer signal 4123

Compressor connection signal 4131

No error detected 4444


Ferrari 348 ABS ECU Error Codes (may also apply to some '89 Ferrari 328's & '95 Ferrari 355's):

11: EMI radio interference, or bad electrical connections, or a failure of one of the two identical ABS ECU control circuit-boards

12: Internal ABS ECU failure

21 - 27: Valve or connecting wire failure or defect in ABS ECU power transistor (21=main valve, 22=left front delivery, 23=left front return, 24=right front delivery, 25=right front return, 26=rear delivery, 27=rear return)

31-34: Lack of signal due to wire breakage or short circuit or internal ECU failure (31=left front, 32=right front, 33=right rear, 34=left rear)

35-38: Intermittent lack of signal due to wire breakage or short circuit or internal ECU failure...or due to faulty electrical contacts...or due to irregular ring gear movement...or due to excessive bearing play...or due to Gap too large or small (35=left front, 36=right front, 37=right rear, 38=left rear)

41-44: Different speed signal to other sensors due to anomalous signal or due to excessive Gap or due to failure to install Ring Gear (41=left front, 42=right front, 43=right rear, 44=left rear)

51-54: Lack of hydraulic efficiency noted at speeds over 40kph (51=left front, 52=right front, 53=right rear, 54=left rear)

55-58: Occasional lack of sensor signal; sensor improperly fitted or Gap too large (55=left front, 56=right front, 57=right rear, 58=left rear)

61: Brake fluid level or pressure too low or contact Grounded or shorted to Power

71-78: Irregular signal at speeds under 40kph (71 & 75=left front, 72 & 76=right front, 73 & 77=right rear, 74 &78=left rear)

*also, keep in mind that some problems do not log ABS error codes, so be certain to verify the pump fuse, the main ABS fuse, the relay fuse, the relay installation, the pump connection, the main valve connector, the ABS valve connector, MIN level transmitter connectors, and the pressure switch connector.


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Storage/Revival of a 348 after years of non-use (the "found her in a barn" situation)

Do the following prior to first starting the engine: It's trivial to pull the spark plugs of a 348 (you can easily reach them all). Pull them and "mist" or fog (really, just squirt) in some (tiny amount) Marvel Mystery Oil into each of those 8 openings.

Now jack the car up with it in 5th gear. At this point you can turn a rear wheel/tire by hand...and since the car is in gear and jacked up, this will turn the engine (slowly and safely).

That will lubricate a fair amount of your engine prior to your first re-start, minimizing the wear and damage from a start after so many years in storage. 348's are notorious for rusty radiators after long term storage, so a "good idea" would be a radiator flush and fill (if possible prior to starting so as to limit the amount of sludge that churns through your water pump).

Same goes for changing the oil, as it will acidize over time (especially with a lack of use).

You also want to drain the old gasoline and refill with new gasoline to minimize sludge and "bad gas."

Ditto again for your brake fluid, but that's not as pressing as lubricating your cylinders and changing your radiator fluid and oil.

If you've got the energy, pull each fuse and coat with Stabilant 22A prior to reinserting into both fuse boxes. You'll also want to coat with Stabilant 22A your ground posts and the metal interiors of your plastic electrical connections. This will help minimize your electrical issues during and after your first re-start.

Also, don't just jump start an old battery (that would work your alternator pretty hard trying to charge it up). You'll want to start with a brand new bat.

Cleaning the dust out of your air filter and box would probably be wise if you've got the inclination to go that next step in taking care of your 348, too.

When you've done as much of the above as your particular patience and skill level allows, be sure to turn your Key to Run, not Start, to give a few seconds for your fuel rails to charge up...Then start her up and stay away from the accelerator pedal for the first 10 minutes as she re-learns your car's setup.

Let that old rubber timing belt get good and warm before you hit any revs over 3,'s going to take a while (if ever) to dekink whatever shape it formed around your pulleys after so much time. As your 348 warms up, start going through the gears at very, very low RPMs; stay in each gear for a minute. Listen for warning sounds and watch for leaks during this process. Twenty minutes of running the engine with no warning sounds, no leaks, stable idle, and reasonable oil/water temps/pressure should be enough to get you back on the road (after the above steps are taken first, of course).


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Post Purchase Prepping:

Congratulations on buying your "new" 348! It's a great Ferrari model.

Even so, you will want to change a couple of things about your "new" 348 to reduce your maintenance, but they are easy to do.

For example, you will want to unplug each of your 348's electrical connectors (everywhere! Especially on grounding points and headlight electrical contacts), and then you will want to apply
Stabilant 22a or Marine Corrosion Block onto all of the exposed metal contacts. This fixes many 348 issues and no doubt prevents far more. It also lasts for years and years.

Replacing your old dash board bulbs and center-mount 3rd brake
light bulbs with modern LEDs lowers your current draw as well as prevents current from flowing in reverse (not good!) when a bulb burns out. This will prevent lots of idiosyncratic problems such as dash lights staying on after you've removed your car key, etc.

And of course, you want to change out the OEM tranny fluid for
Red Line's "Superlight Shock Proof Gear Oil" (or 75w90NS) so that you can actually shift into 2nd gear while your 348 is still cold.

Likewise, you will want to install a new Optima car battery (low or dead batteries draw too much current from the 348's alternator, leading to premature alternator burnout and a host of difficult-to-diagnose electrical issues). This also means that you shouldn't jump start a dead 348. Install a new (or charge up an old) battery rather than jump start a 348.

Ernie suggests that you get some Permatex black silicone. It costs about $3 for a tube of it. Then after you have taken the car out for a nice Italian tune-up-drive (the heat will help evaporate moisture that's already penetrated these old units), jack up the rear, remove both rear wheels and inner fender liners, unbolt/unplug and pull out both of the exhaust ecu's and seal them up good with the silicone (seal everything except the electrical wires, of course). That should keep the moisture from getting inside the cat ecu (the main killer of these $400+ parts), and then it shouldn't be able to build up the condensation from sitting all night.  (exhaust ECU)

Adding an inexpensive ($130) automatic fire extinguisher is **highly** recommended, too.

Replace your low beam 9006 head light bulbs with modern 9012 HIR bulbs.

These are pretty simple (and inexpensive) things to do. You *can*
change your tranny fluid. You can replace old technology light bulbs with modern LEDs (it's just changing a light bulb!). You can wipe a little liquid onto your metal electrical contacts (especially on your Grounds and spark plug coils). You can change a car battery. I bet that you can strap in a fire extinguisher, too (remember, they are made to give you and/or your passenger a little extra time to exit the vehicle; they aren't going to save the car itself very often - then again, they aren't going to do either if you don't buy and install one).

I would also recommend that you inspect each of your relays. The metal exteriors should not have visible corrosion. The copper pins/legs should not have visible corrosion, either. The plastic exteriors should not show signs of overheating/burns. The part numbers on each relay should likewise be double-verified (incorrect relays can work, but typically cause other problems) as correct.

NOTE: Bosch 0332014113 relays have now replaced/superceded the older Bosch 0332014140 relays (same circuit diagram on both). There seems to be a general consensus as a good idea for replacing the two old 0332014140 relays for the left and right fuel pumps (found in the passenger footwell) as well as replacing the two old 0332014140 relays for the left and right fuel injectors with the newer (and cheaper!) 0332014113 relays.

These simple improvements will greatly lower your 348 maintenance; reducing your down time and costs while enhancing your drive time.


 Emergency Roadside Kit

Also: Verify that both #31 (see below) hose clamps are sufficiently tight (but not choking the hose).

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Emergency Roadside Kit

Do you want to be prepared? Do you have the factory 348 toolkit in your front trunk?

What minimal things that can be packed in the front trunk to cover most dead-on-the-road phenomena.

Why are cars on the side of the road?
#1 is clearly running out of gas. Whatever happened to Pennzoil's great Rescue Fuel (and no, the internet rumors that it was just kerosene aren't true)?

Starter fluid would be good to have on-board, anyway.

#2 is probably a dead battery. There are small products for that:

#3 I'd think would be a flat tire. Easy:

#4 might be a coolant hose giving way. Easy patch:

With the above, plus an adjustable ratchet, a single pair of vice grips, a couple of spare fuses, a short length of electrical wire, hand-cranked flashlight (no batteries), and a Leatherman, I'd bet that you'd be able to cover 80% of the most common roadside "emergencies."


Add a small emergency jack, one 9006 low beam headlight bulb (or better yet, a 9012 HIR low beam bulb), one brake light/running light/blinker bulb (1156 regular), one spare alternator belt, a small first aid kit, and you'd probably have 90% of the most common roadside emergencies covered.


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Model Differences (re: maintenance costs of 348 vs 355)

The costs are comparable, but keep in mind that the 355 is more complex. The F355 has driver-adjustable shocks...which means that compared to a 348 that you've got an extra F355 suspension ECU, 4 extra electric adjustment motors, adjustable shocks, etc.

The 355 Spider also has power seats, so you've got extra motors there, too.

The F355 Spider has a power top, so you've got a top ECU ($
2,500), an extra motor, and hydraulics.

Likewise, the 355 has power you've got an extra pump, extra pulley, more hydraulic lines, etc. Your 355 *will* have
power steering problems eventually.

And the F355 motor has 5 valves per cylinder instead of the 348's 4 valves per cylinder (which translates into different parts and labor costs when you are doing a top end job). 355 valve problems are known issues, and not inexpensive to repair.

The F355 F1 cars have an entirely different transmission that has extraordinary maintenance costs (an F1 tranny pump can run
$16,000 just for the part, not labor, to replace).

On the 355 the F1 pump will not run until the key is on and the transmission will not shift until hydraulic pressure is up. If the car is parked in gear that means that you have to wait about 30 seconds or so before you can put the car into Neutral to start. However, F1 pump failures aren't the main maintenance problem; people are spending LOTS more keeping 355 motors running in my shop than transmissions so I wouldn't say the F1 sky is falling. In the shops in Nor Cal almost everyone has a 355 taken apart rebuilding the top ends. Compared to that F1 problems are rare. *thanks, RifleDriver

(The 360 has a switch on the door latch to start the F1 pump so that by the time you are seated and have your belt on the car is ready to start.) Also: the F355 F1 pump failure is typically due to the inexpensive F1 relay failing. Replacing that $44 part proactively saves much on F355 maintenance costs.

The 355 has different exhaust manifolds...the OEM manifolds are good for no more than 30,000 miles. You **will** be paying $2,500 or more to replace those every 30,000 miles.

The 355 also has different valve guides (pre-mid-1998 models) which are apparently only good for some 25,000 miles.

In addition, the 355 comes with dual air bags, which may become more problematic as those systems age. Air bags should be replaced every ten years. 355 Air Bags Spontaneously Deploy and in addition to air bag aging problems, the air bag ECU costs $1,200 to replace, which can be killed by simply trying to start a 355 with a low battery.

355 engine life is also quite short. "I have yet to see a 355 go 100k but I have rebuilt quite a few before 50K."

What you are getting in the 355 is more refinement and more power and more luxury. This is not for free.

In contrast, the 348 is a vastly less complex machine. It has none of the above, with the pros and cons that come with their absence.


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348 VINs

How To Read Ferrari VINs

348 Challenge "factory" cars all US/NA (32tb and 13 ts).
S/N's: 97869 - 98906. thanks, Dr.T348

348 Competizione 96064-99143

348 GTB 96655-99697

348 GTS 96824-99197 Thanks, mdraeger

348 Series Speciale 92812-95820

348 Spider chassis nos. are between 94504-99947

348 TB 81617-96679

348 TS 82572-96964 thanks, Ingenere



348's do not get much problematic rust. The rare areas that may see rust are typically headlight backing plates, door sills/bolts/wiring, sub-frame engine mount pillars, radiator metal locking tabs for the (plastic) hose caps, rear A-pillars on TS's/TB's, heat exchangers, convertible top snaps/fasteners, seat rail mounts, and catalytic converters.

pic credit to Daniel P

Maintenance Expectations

Ferraris do require periodic maintenance. It's not unreasonable, but it's not economy-class cruising, either. If you've paid for maintaining an active rally car, road racer, circuit car, dragster, yacht, sailboat, large powerboat, aircraft, or race horse, then the maintenance expenses on your Ferrari won't shock your system.

You are doing yourself right by investigating said expenses prior to your purchase. In my opinion, you will *never* see a Ferrari honestly operated for less than $1 per mile, even if you are doing your own wrenching (recommended!). If you plan on driving it 12,000 miles per year, then you *will* pay more than $12k in annual maintenance/insurance/operations.

These cars are a lot of fun. A hoot to drive! Great on the track, too. The price to pay isn't outrageous, and to many like myself, well worth it, but it's not free driving, either. Just be prepared and you'll be fine.

Personal 348 Maintenance Log

Itemized 348 Maintenance Expenses

Typical 348 Maintenance Expectations:

Most 348 owners have pretty good luck if they apply Stabilant 22a to all of the electrical connections or replace the connectors with a Dave Helms Scuderia Rampante kit (this is a one-time thing), change their oil at or before every 5,000 miles, and change their timing belt at or before 5 years time (or 30,000 miles...but few people drive their 348's that far in 5 years). This is known as Ferrari’s "30K Service" and it is a good time to upgrade to Hill Engineering belt tensioners and clutch slave bearing as well as to a Dick Jordan rebuilt water pump.

If you've read the 348 Primer's section on how to start your 348, follow it, and keep proper air in your tires, then the above schedule (plus replacing brake fluid and pads every 5 years or so) will get you through years of enjoyable ownership and thousands of miles of awesome 348 driving.

It's not that complicated. I mean, change or clean your air filter and spark plugs once every few years...ditto for your tranny fluid...your windshield wipers...every 7 years or so replace the cheap-but-good Interstate 34R battery…repack your wheel bearings…and you've pretty well covered your typical 348 bases.

Then every decade or so you can have your shocks rebuilt and new bushings may even have to replace a boot cover or two in that time...ditto for some of your light bulbs and the two $6 gaskets for your fuel filler line.

Your carpet and seat leather will wear a bit to show the world that you are actually enjoying your 348 (patina!)...replace per individual taste.

Same goes for A/C comfort in regards to recharging the system.

In the meantime...


Pay attention to your 348's warnings. For instance, keep a clean garage floor so that you can quickly see if your 348 starts leaking. This might be something as simple as a loose gear oil plug bolt that needs to be tightened (a free fix), or something a bit more complex such as flywheel grease or brake/clutch fluid that is giving you advance notice before the really serious damage begins. Perhaps the "leak" is just air conditioning condensation or normal coolant overflows, or perhaps you've got a loose hose clamp, rusted/corroded radiator, or heater core.

Likewise, listen to your car. 348 bearings, transmissions, belts, brakes, exhaust note, and suspension (and more) will often give you an audible warning (even squeal) prior to major damage setting in. Feel your car. Notice if your engine/exhaust is heating up the air more than normal (or if your cats are glowing red). Notice if your ride quality deteriorates/bounces. Smell your car. Do you smell a fuel leak or a burning electrical connection?

Is your clutch slipping? My clutch plates were worn to the rivets - way past spec, so my clutch was slipping when I applied full power in any of the high gears. Well, the pressure required to operate this sort of diaphragm spring increases as the clutch plates naturally wear. Ferrari did not leave a great deal of overload tolerance on the slave cylinder throw-out bearing unit so it went pop.
Lesson: Dont ignore a slipping clutch even if it's only a tiny bit. Thanks,

Do not ignore any Check Engine or Slow Down lights! Pull your codes and fix your problems.

Do not drive an unsafe car. Please.

Practice safety. Is your fire extinguisher in your engine bay and cockpit and newly charged? Are your seats and seat belts secure and unfrayed/uncracked? Do you have a seatbelt escape tool (or even a knife on board)? A helmet for the track? A track roll cage for racing? New tires, properly inflated and balanced? All brakes working, ABS functioning, and no brake noises? Does your parking brake work?



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