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Thread: Ferrari 348 TS 1991 engine vibration under load

  1. #1
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    Haydar Kirmani
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    Default Ferrari 348 TS 1991 engine vibration under load

    Hi all

    I have a 1991 Ferrari 348 TS European Spec. Recently the car has developed a judder when accelerating at low speed in a high gear. So for example, if rpm is around 2500rpm in third gear and I squeeze the accelerator pedal, the car judders rapidly until the revs climb past 4000rpm and then it clears up and then revs happily to the redline. Car is running fine apart from this.
    .
    The car has covered around 30,000 miles, the CATs have been replaced with straight through pipes. The problem started after the car was left without starting for some months during which the battery went dead. I had the battery recharged and it starts fine.

    I performed the reset by disconnecting the battery for 10 minutes and then letting it idle for 20 minutes. However no change.

    Does this sound like an electrical (ignition) problem or a fueling one?

    All help greatly appreciated.

    Thanks

  2. #2
    Nosevi's Avatar
    Nosevi is online now There's an outside too? Where? Super Moderator
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    Could be throttle position sensor or MAFs. Id start by cleaning all contacts on the TPS connections and MAF connections as well as givving the actual MAFs a clean with MAF cleaner. Might not be this but itd rule it out and is easy to do.

  3. #3
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    Allan Fisher
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    Default Battery

    Quote Originally Posted by haydar View Post
    Hi all

    I have a 1991 Ferrari 348 TS European Spec. Recently the car has developed a judder when accelerating at low speed in a high gear. So for example, if rpm is around 2500rpm in third gear and I squeeze the accelerator pedal, the car judders rapidly until the revs climb past 4000rpm and then it clears up and then revs happily to the redline. Car is running fine apart from this.
    .
    The car has covered around 30,000 miles, the CATs have been replaced with straight through pipes. The problem started after the car was left without starting for some months during which the battery went dead. I had the battery recharged and it starts fine.

    I performed the reset by disconnecting the battery for 10 minutes and then letting it idle for 20 minutes. However no change.

    Does this sound like an electrical (ignition) problem or a fueling one?

    All help greatly appreciated.

    Thanks
    How long have you driven it since reconnecting the battery, it may still be learning.

  4. #4
    Pangea's Avatar
    Pangea is offline Rear lights like a farm gate - The Ferrari 348 Club Member
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    From what you describe it sounds like an under load ignition misfire.

  5. #5
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    Haydar Kirmani
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    I've checked the plugs and they are all fairly new and none seem to be bad or bogged. The resistance across the MAF are 382ohms each as per my348.com.

    The car is worse when cold and gets better as it warms up. However it never seems to complete go away. On another forum someone suggested that it might be a bad CV joint or greese packing in the flywheel???

  6. #6
    Pangea's Avatar
    Pangea is offline Rear lights like a farm gate - The Ferrari 348 Club Member
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    Quote Originally Posted by haydar View Post
    I've checked the plugs and they are all fairly new and none seem to be bad or bogged. The resistance across the MAF are 382ohms each as per my348.com.

    The car is worse when cold and gets better as it warms up. However it never seems to complete go away. On another forum someone suggested that it might be a bad CV joint or greese packing in the flywheel???
    Remote diagnosing can be difficult but I can't see the CV joint being the issue. It wouldn't get better with time for a start. The flywheels can be a problem but normally causes a poor starting issue. It still sounds like a misfire as they quite often improve when the engine is warmer as there is not quite the same loading involved when cold.. I would be looking first at the HT side of things. Leads, Coil, plugs etc. Its just guesswork from afar though Im afraid. I could write an essay but its easier if you have a read here if you like. I don't know how familiar you are with mechanics. Maybe something will be of help to you and make sense . Good luck.

    http://www.autotap.com/techlibrary/d...g_misfires.asp

  7. #7
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    Haydar Kirmani
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    Tried pulling up the handbrake and then releasing the clutch with between 1500-2500 rpm. I was hoping to mimic the load conditions are see if there is any misfire. However under these conditions there was no vibration/judder! Does this mean it is more likely to something to do with the axles?

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