Odd and Intermittent Misfire 1992 512tr | FerrariChat

Odd and Intermittent Misfire 1992 512tr

Discussion in 'Boxers/TR/M' started by oldcoin, Jul 16, 2019.

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  1. oldcoin

    oldcoin Formula Junior

    May 1, 2006
    258
    Reno NV
    Full Name:
    Tony Mitchell
    Here is what happens. I have repeated this 5 times with no variance in results.

    1. Start the car and go for a leisurely drive in 90 degree weather.

    2. At about the 20 minute mark on the drive the car loses power to the extent that acceleration is impossible. Car still runs fairly smooth, just no power.

    3. After several seconds car returns to normal with full and crisp power and throttle response.

    In every drive this drop in power happens at about the 20 minute mark and during said drive, the problem never reappears even after 1 1/2 hours. There is no sign of unburned gas.

    Has anyone had this experience and has anyone discovered the problem and fixed it?
     
  2. xplodee

    xplodee Formula 3

    Jan 3, 2017
    1,101
    Allentown, PA
    Full Name:
    Tim
    First step is to figure out what bank the problem is occurring on. Second step is to determine if it's fuel or spark related. Then trouble shoot from there. Do you know the basic trouble shooting steps to perform the first and second steps above or would you like me or someone else to describe it?
     
  3. oldcoin

    oldcoin Formula Junior

    May 1, 2006
    258
    Reno NV
    Full Name:
    Tony Mitchell
    I am familiar with the trouble shooting routine. Since the episode happens only once and only for a few seconds how would I isolate which bank is the culprit?
     
  4. xplodee

    xplodee Formula 3

    Jan 3, 2017
    1,101
    Allentown, PA
    Full Name:
    Tim
    Unfortunately the only thing you can do is wait till it becomes permanent or proactively start replacing parts without really knowing the results. Romano and others will have better input than me
     
  5. turbo-joe

    turbo-joe F1 Veteran

    Apr 6, 2008
    8,866
    southwest germany and thailand
    Full Name:
    romano schwabel
    as tim says:
    wait until it becomes permanent or just check when the failure will happen
    I wonder why it always happens after 20 minutes and after then all ok again ???
     
  6. ross

    ross Three Time F1 World Champ
    Owner Silver Subscribed

    Mar 25, 2002
    36,206
    houston/geneva
    Full Name:
    Ross
    would this not show up on the computer if you ran a diagnostic?
     
  7. OptimusPrime

    OptimusPrime Formula Junior

    May 10, 2011
    284
    Florida
    Full Name:
    Tom
    I have an 88TR and had similar problem but was not always at the same time. Mine would backfire and drop a bank once in a while on hot days only after driving for 20 min to an hour. I first changed out rotors and distributors and then ohmed out and trimmed all plugs and coil wires...the bank that dropped had a bad connection at the cap (screw pin barely hitting the end of the wire causing arcing and that stopped that side bank lights from coming on once I fixed that. I still felt like low power when it started backfiring after it got warm, so next I took a blower and sent air into exhaust (engine not running) and used soapy water to spray and found an exhaust leak. Thought for sure that would fix it but still backfiring and dropping bank (without indicator lights). I then ordered a new coil and ignition module and the module showed up first, was only $45 and that was the problem. I guess when my ignition module got warm, especially on a hot day, it did not work correctly. If I were you I would swap sides with your ignition modules and try it and then swap the coils and see if the side that drops changes, only takes a few minutes.

    Good luck
     
  8. MOSS

    MOSS Formula 3

    Apr 28, 2004
    1,619
    Nice information


    Sent from my iPhone using FerrariChat.com mobile app
     
  9. Newman

    Newman F1 World Champ
    Consultant Owner Professional Ferrari Technician

    Dec 26, 2001
    14,092
    Canada
    Full Name:
    Newman
    You can inspect the rubber mounts the fuel pumps sit in inside the tanks. They fall apart due to age and today's fuels resulting in contamination in the tanks or tank.
     
    MOSS likes this.

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