348 spider hard starting | FerrariChat

348 spider hard starting

Discussion in 'Technical Q&A' started by jrobbins, Aug 12, 2005.

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  1. jrobbins

    jrobbins Karting

    Aug 9, 2005
    93
    Ottawa, Canada
    Full Name:
    J.D. Robbins
    When my car is warm (after driving), it is very difficult to restart.

    It turns over 20-30 times. I have to turn the key off and back on and if I'm lucky it will almost catch and then finally start.

    The car doesn't do this when it is cold.

    The dealer told me to put fuel injector cleaner into the gas and run it. I did that but it didn't seem to help.

    Ideas?

    So far FerrariChat Forum members are 2 for 2 in fixing my issues! Go FerrariChat Users, Go!

    J
     
  2. No Doubt

    No Doubt Seven Time F1 World Champ

    May 21, 2005
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    The hard start when warm is a pretty common 348 malady. The easiest, cheapest fix is when the hard start is caused by your fuel mixture being too lean. When that's the case, you simple turn the screw under each of your two MAFs until your 348 starts up promptly.

    But there are many other things besides a lean mixture that can cause hard starts when warm such as a dying fuel pump, bad fuel accumulator, bad fuel injector (or perhaps even more than one bad injector), bad fuel pressure regulator, etc.

    My advice is to try the cheapest fix first all the way to the most expensive fix last, stopping of course, when you get your starting fixed!
     
  3. jrobbins

    jrobbins Karting

    Aug 9, 2005
    93
    Ottawa, Canada
    Full Name:
    J.D. Robbins
    Thanks for your advice.

    Both of my fuel pumps were recently replaced prior to buying the car from the dealer. I would assume that the problem is not the fuel pump.

    Regarding turning the screw under the MAF's: two screws to turn? Should they both be about the same way along?

    Perhaps it would be more prudent to have a 3 gas test done while doing this so that I get the proper stocheometric A/F ratio?

    Lastly, I'll gladly try turning the screws, but do you do one or both at the same time? Anyone have a picture of where they are located? On my delorean they are as clear as day, can't miss them. Ferrari?

    Thanks again,

    J
     
  4. No Doubt

    No Doubt Seven Time F1 World Champ

    May 21, 2005
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    Yes, get the proper A/F ratio with an analyzer if that's an option, but you can first test to see if mixture is causing hard starts.

    Pull the black data cables off both MAFs. The outermost pins, number 1 and #6, will give you a resistance value on your Ohm-meter. Factory baseline is 383 Ohms.

    So first off, measure your resistance on both MAF's. You can always reset this back to your baseline now that you know it.

    Now pop the blue caps off of both MAFs. Turning the screw beneath that cap will change your MAF resistance as well as simultaneously changing your A/F mixture.

    Both MAFs should aways be set to the same resistance level.

    Adjust.

    Reattach your MAF data cables. Start your 348.

    If that fixes your problem then you got out cheap!


    If not, then start replacing your fuel accumulators.

    If still not, then replace your fuel pressure regulators.

    If still not, then replace your fuel injectors.

    If still not, then replace your fuel pumps.
     
  5. Miltonian

    Miltonian F1 Veteran

    Dec 11, 2002
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    If it's cranking over fine but not starting, it's probably your flywheel.
     
  6. ernie

    ernie Two Time F1 World Champ
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    Nov 19, 2001
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    I agree with what that.
     
  7. No Doubt

    No Doubt Seven Time F1 World Champ

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    Wow! I have *never* heard that fix before. Hey, you're the expert, and I've seen you give valid tips and fixes to plenty of people, so it's not that I'm doubting you, it's just that I'm stunned.

    The guy's 348 starts fine cold, but takes 30 seconds to start when warm (per his first post), and it might be his flywheel?!

    I think that I'm about to learn something about 348's today on this thread.

    Wow! Please, you've got to explain this one (otherwise I'll be shaking my head all weekend, getting dizzy).
     
  8. Miltonian

    Miltonian F1 Veteran

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    #8 Miltonian, Aug 12, 2005
    Last edited by a moderator: Sep 7, 2017
    It's hard to believe that the flywheel would cause a starting problem, but it's true, there have been numerous threads about this, and several owners can give firsthand testimony to it (including me).

    In a nutshell, the 348 flywheel is a "Voith bi-mass" style. It has parts inside it that are designed to absorb shock and vibration, in conjunction with special Kluber grease inside the casing. When the grease gets diluted by leaks from the transmission shaft seals, or if the grease is able to escape from inside the flywheel, the unit goes out of balance, and a triggering signal is sent to the Motronic system, which prevents the engine from starting. If the engine is cold, the grease tends to have greater viscosity, so the engine is more likely to start. If the engine is warm, the grease thins out and the flywheel more easily goes out of balance.

    The solution is to remove the clutch housing from the car (not difficult), remove the flywheel assembly from the housing, disassemble the flywheel, clean up the mess, repair the leaks, repack it with Kluber grease, and reassemble. Starting should be vastly improved.

    On my own car, repacking the flywheel (with no other work done) brought about instant improved starting. The engine always starts, hot or cold, with less than 1 second of cranking. Before, it would sometimes take 10 minutes of off/on cranking to get it to fire.

    For a quick check, look under the back of the car, right at the center, at the bottom of the clutch housing. You'll see a perforated panel attached with four screws. Is there obviously fluid dripping from there? If you remove the panel and reach up inside, is it covered with gloppy liquid residue? If so, then you probably have a flywheel problem, and it won't get better by itself.

    Here is a picture of the inside of my 348 flywheel, taken after cleaning up the old grease, before regreasing and reassembly.
    Image Unavailable, Please Login
     
  9. No Doubt

    No Doubt Seven Time F1 World Champ

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    Thanks for the explanation!

    I would have lost money on a bet about that fix.

    I've noticed that several threads have mentioned that it's easy to remove the clutch from our 348's.

    For the 348 dillatante, is there pressure to be concerned about? Do we need to have something underneath to hold the weight when the clutch is removed? Do we have to bleed the clutch line and/or brakes after we've removed the clutch? ditto for flywheel (which I presume can only be accessed once the clutch is removed first).

    Are special tools required for disassembly or aligning upon re-assembly?

    And here is a good question, can the 348 owner who started this thread simply repack his clutch/flywheel with grease, saving other steps of disassembly, in order to test if this is his problem (e.g. no cleaning, leak fixing, etc.)?
     
  10. Miltonian

    Miltonian F1 Veteran

    Dec 11, 2002
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    As far as I know it's impossible to get grease into the flywheel without removing the clutch housing from the car, and without removing the flywheel from the housing. There is no way to get the filler plugs off.

    I'll try to find Vincent's great thread on the clutch/flywheel job and post a link.

    Edit: Let's see if this link works.

    http://70.85.40.84/~ferrari/discus/messages/256120/271073.html
     
  11. Miltonian

    Miltonian F1 Veteran

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    Forgot to mention: the other symptom of the flywheel problem, without taking anything apart, is just to listen for the distinctive "rattling" sound at the back of the car when cranking over, or when shutting the engine off. This is from the parts inside the flywheel slapping around without enough grease (or diluted/thin grease) to damp out the excessive movement.
     
  12. No Doubt

    No Doubt Seven Time F1 World Champ

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    When hot, try putting your 348 into 1st gear, depressing the clutch, and then starting.

    If she starts with the clutch down and gear in 1st when hot, but otherwise has trouble starting when warm, then it would seem that your flywheel would need to be repacked with new grease.

    Otherwise, see the fuel mixture, fuel pressure regulator, fuel injector, fuel pump et al fixes.
     
  13. jrobbins

    jrobbins Karting

    Aug 9, 2005
    93
    Ottawa, Canada
    Full Name:
    J.D. Robbins
    Thanks to everyone for their advice. Here's an update:

    My car starts on the second crank when cold, everytime.

    After driving for 20 minutes or more, it takes 30 cranks or more to start.

    It will not start when hot even with the clutch depressed in first gear. I'm hoping it isn't the clutch assembly.

    As for the MAFs, that's my next check. Are they located near the ECU or on the air intake in the engine bay? I'm assuming the engine bay.

    I've got my multimeter and a copy of this printout ready to go test!

    Last question: The screw to change the A/F mixture goes clockwise lean/rich? Roughly how many turns or is it super sensitive? ie: quarter turn is too much?

    I'll give it a run once I hear back from all of the experts here!

    Thanks again!

    J
     
  14. jrobbins

    jrobbins Karting

    Aug 9, 2005
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    Ottawa, Canada
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    J.D. Robbins
    Whoops, last question:

    383 omhs on the MAFs or on the cables I just took off? Check pins 1/6 on which part?

    When adjusting resistance on those screws, when resistance is increased, mixture is going which way, lean or rich? Since my car isn't starting, I assume I need to go more rich?

    Thanks again.

    J
     
  15. No Doubt

    No Doubt Seven Time F1 World Champ

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    That hurts to even think about. That's too many cranks!

    If you don't hear a rattle behind you from the flywheel and if it won't start even in first gear, then the problem is unlikely to be your clutch/flywheel.

    The factory workbook says that clockwise thickens the air, so counter-clockwise should enrich your fuel. Your mafs are located near your air filter in the engine bay. They are black. They each have a black data cable that connects to them. They each have a blue cap on them.

    I've got to say, though, that a lean fuel mixure is unlikely to be *your* particular problem. 30 cranks to start when hot is indicative of something more severe than a bad fuel mixture ratio.

    That being said, there is no cost for parts...so changing your A/F mixture is a free thing to check.

    If it isn't your flywheel or your mixture, then I'd guess that you have a leaky fuel injector or a bad fuel pressure regulator.

    But before going there, you'll probably want to pull one of your spark plug cables while someone else turns your ignition key so that you can verify that you have a spark. That too is a free test.

    Likewise, pulling the vacuum hose off of each of your fuel pressure regulators is another free test. If you see gasoline under either vacuum hose, then you've got a bad fuel pressure regulator.

    Let us know what you see from your 3 free tests.
     
  16. No Doubt

    No Doubt Seven Time F1 World Champ

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    383 Ohms on your MAFs is merely the default factory setting. When you remove the black data cable that goes to each MAF, you'll see 6 male pins on each MAF. The outermost pins, numbers 1 and number 6, are what you'll attach to your multimeter (engine off). Measuring this resistance value first gives you your own personal baseline (i.e. you can always reset your MAFs to this value later). This resistance value also lets you insure that both MAFs are on the same A/F setting.

    As for being too rich or too lean, you don't know yet if you have a spark, if your engine is flooded, or if your engine is starved for fuel.

    You've got to do the 3 free tests first.
     
  17. jrobbins

    jrobbins Karting

    Aug 9, 2005
    93
    Ottawa, Canada
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    J.D. Robbins
    I took my car to the shop after following all of the expert advice in this forum.

    It turns out that the fuel pressure regulators were bad in my car. I couldn't generate the correct fuel pressure to start the car when warm and often the car would stall when I was driving.

    Now it all works properly.

    J
     
  18. Ricambi America

    Ricambi America F1 World Champ
    Sponsor Owner

    Whoa, good feedback.. thanks for closing the loop on this one! I would have put money on the flywheel --- but as chance would have it, the gold star goes to "Brother No Doubt" for his diagnosis.

    Don't worry ernie & Miltonian, you're still have your honorary degrees :)



     
  19. Miltonian

    Miltonian F1 Veteran

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    I can see how a problem with the fuel pressure regulators might cause a starting problem or a running problem, but I can't see why it would make any difference whether the engine was hot or cold. According to the manual, the regulator is supposed to maintain a pressure of 3 bar in the system while the engine is shut off. There are no electrical parts in the regulator, just a fuel inlet and outlet fitting, and a diaphragm operated by engine vacuum.

    The fuel flows from the tank, to the pump, to the filter, to the fuel injector rail, to the regulator, and back to the tank. There is a No-return valve on the pump. So if the regulator was the problem, the diaphragm was open or had a hole in it, releasing the pressure back into the tank. I don't see how temperature would affect this. If there was a hole in the diaphragm, there would never be enough pressure in the system, it would just release into the return line. If the diaphragm was stuck open, why would it close due to changes in temperature?

    If it's fixed, great! But I'd like to hear an explanation of how temperature would affect the operation of the regulator.

    Extra note: The classic symptom of a hole in the diaphragm on the pressure regulator is to pull off the vacuum hose and see if fuel comes out. The fuel (which is under pressure) should not be able to reach the manifold side of the regulator.
     
  20. No Doubt

    No Doubt Seven Time F1 World Champ

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    The cold start circuitry isn't activated when the engine is warm. When cold, that cold start system dumps extra fuel and/or extra air into the cylinders...potentially masking some problems that are in the system (if any).

    We could probably devise some sort of 348 test for the cold start circuitry by figuring out how to activate it even when the engine is warm. If that activation starts the car when warm...while the car wouldn't start without it, then you can narrow down the hard-start problem.

    I'd also add that a few lazy (or greedy!) shops will often replace the fuel pump(s) which **will** often fix the hard start problem for a while (at least until the hole in the fuel pressure regulators grows a bit) simply because when new they tend to pump out just a bit more pressure than spec. That's a pricey and temporary fix when the case turns out to just be bad fuel pressure regulators.
     
  21. jrobbins

    jrobbins Karting

    Aug 9, 2005
    93
    Ottawa, Canada
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    J.D. Robbins
    As it turns out, the car was hard to start when both hot and cold. I didn't really know how it normally started since I bought the car with the regulators not working properly.

    Now the car starts promptly on the second crank.

    Prior to me buying the car, the fuel pumps both had been replaced by the dealer, so it may have masked the regulator problems for a while. It did appear that the problem was growing worse, eventually I sometimes could NOT start the car.

    However, with the regulators being replaced, the car starts just fine.

    J
     
  22. Miltonian

    Miltonian F1 Veteran

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    Glad to hear that your car is starting fine now, hot and cold. Did your shop have to replace both of the fuel pressure regulators, or just one of them? Seems a bit curious if both of them went bad at the same time.

    Just to quickly rehash the situation, the 348 fuel system (according to the book) is supposed to operate at approximately 54psi, meaning that the pump puts out enough volume to maintain that pressure whatever the load on the engine, as revs increase and more fuel is required. The pressure regulator opens a variable amount according to the amount of vacuum in the intake manifold (as the throttle is opened and closed), and as it opens and closes, it releases extra fuel to be returned into the tank. When the engine is shut off, and the vacuum source is eliminated, the regulator closes off the return line to the tank, and holds approximately 42psi in the fuel lines.

    If the regulator is defective, it allows an excessive amount of the pressurized fuel to flow back into the tank, decreasing the available pressure at the injectors. The amount of fuel delivered through the injectors to the individual intake ports is determined solely by the length of time that the Motronic ECU tells the injector to open, and by the amount of pressure available to force the fuel through the injector once it has opened. If there is not enough pressure in the system (due to a bad pump, or a bad regulator), then the fuel can only dribble into the port in an insufficient quantity, and can not be atomized for proper mixture with the intake air.

    If the regulator is leaking slowly, the pump may eventually be able to generate enough pressure to overcome the loss back into the tank. But if the regulator is leaking badly, it would not matter how much pressure the pump put out, the fuel would simply flow back into the tank.
     
  23. ferrarifixer

    ferrarifixer F1 Veteran
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    While "No-doubt" is obviously very clued up about 348, the fact he suggested pressing the clutch may affect the potential flywheel problem concerns me a little as to his "hands on" experience.

    The flywheel turns the whole time the engine turns, whether clutch is in or out. The starter motor uses the flywheel to turn the engine.

    The grease in the flywheels can be topped up without removing the clutch assembly, but of course, this won't fix the cause, just the symptom.

    When the grease in the flywheel is gone or thin, the crank sensor gets confusing information form the "chattering" crankshaft... hence the common cause of poor starting. And if the grease is marginal, then it's worse when hot as it has thinned more.

    Bottom line.... well done No-Doubt for suggesting fuel checks, but history shows most poor starting 348/355 cars (especially if flyweel is rattling), will be due to the flywheel grease.
     
  24. Miltonian

    Miltonian F1 Veteran

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    "The grease in the flywheel can be topped up without removing the clutch assembly."

    How so? I would say that it's impossible to do this, based on my one-time experience.
     
  25. ferrarifixer

    ferrarifixer F1 Veteran
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    If you turn the flywheel around, the 3 little filling caps will line up with a window in the bell housing, where you can then put your grease in... but you still need the silencer off, and if you've done that then you're so close you may as well do the whole job properly.....
     

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