83 QV Idle misfire issue after going hard | Page 2 | FerrariChat
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83 QV Idle misfire issue after going hard

Discussion in '308/328' started by FerrariMech1, Mar 12, 2018.

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  1. FerrariMech1

    FerrariMech1 Karting

    Dec 14, 2014
    78
    Dayton, OH
    Full Name:
    Michael Wilson
    #26 FerrariMech1, Mar 23, 2018

    I apologize, I must've gotten everyone mixed up.
     
  2. johnk...

    johnk... F1 World Champ
    Owner

    Jun 11, 2004
    11,276
    CT
    Full Name:
    John Kreskovsky
    #27 johnk..., Mar 23, 2018
    I have a question. Why does it rev to 2k on a hot restart (video) then drop back to the correct idle? Granted, my car is an 85 but hot or cold, when I start it, it initially comes to around 1k and stays there if warm. If cold it rises slowly to about 3k and hangs there until it warms up. I'm the original owner and it's behaved that way.
     
  3. FerrariMech1

    FerrariMech1 Karting

    Dec 14, 2014
    78
    Dayton, OH
    Full Name:
    Michael Wilson
    #28 FerrariMech1, Mar 23, 2018
    On unmolested US cars there is a "Cold Start Air Valve" which bypasses the throttle to keep the RPMs high in order to heat the cats ~3k is what it is set for.

    My car has this feature disabled, but rather than taking it out entirely, I just hooked the vacuum line up to the plenum which I believe causes what you're seeing
     
  4. johnk...

    johnk... F1 World Champ
    Owner

    Jun 11, 2004
    11,276
    CT
    Full Name:
    John Kreskovsky
    #29 johnk..., Mar 23, 2018
    Thanks for the explanation.
     
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