Mondial stumbling question...ignition ECU? | FerrariChat
Buy

Mondial stumbling question...ignition ECU?

Discussion in 'Technical Q&A' started by Birdman, Jun 4, 2005.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, Skimlinks, and others.

  1. Birdman

    Birdman F1 Veteran

    Jun 20, 2003
    6,689
    North shore, MA
    Full Name:
    THE Birdman
    #1 Birdman, Jun 4, 2005
    Hi All,
    I'm having an intermittant problem with the '83 Mondial QV, stock ignition system. Occasionally, the car stumbles or hesitates, once in a while backfires, while at the same time the tachometer goes nuts, jumping all over the place. Then the problem goes away, the car runs fine, the tach works fine. This happens seemingly at random, when the car is hot or cold, but mostly at lower revs, such as putting though town. Higher revs seems to "clear" it. Since the hesitation is 100% correlated with tach freak-out, I'm assuming that this is a loose connection at one of the ignition ECUs and plan to pull the connectors and clean them tomorrow. Since I have to put the car on the lift and pull the wheel well liner to do it, anything else I might check in there while I'm at it?? Could anything else cause this? Would an ECU be "bad" but work sometimes?

    Thanks in advance...

    Birdman
     
  2. Darolls

    Darolls F1 Veteran
    BANNED

    Jul 2, 2003
    7,782
    Full Name:
    Sparky
    #2 Darolls, Jun 4, 2005
    Has the fuse block been upgraded?

    The originals caused a myriad of electrical problems.
     
  3. Philjay50

    Philjay50 Formula Junior

    Jan 16, 2003
    595
    Chester, England
    Full Name:
    Philip
    #3 Philjay50, Jun 5, 2005
    I will share a similar problem I had with mine,84 QV. The car would start ok and run fine, but them it would go "off" and the rev counter would drop to zero, then it would pick up again.It was going off on one bank of cylinders, in my case the front. It did this on a totally random basis. The problem was solved by changing the flywheel sensors. All is now fine. One other thing, I have just changed my HT leads and cannot believe the improvement, I suspect the old ones were original, and they literally fell apart.
    Good luck
     
  4. Birdman

    Birdman F1 Veteran

    Jun 20, 2003
    6,689
    North shore, MA
    Full Name:
    THE Birdman
    #4 Birdman, Jun 5, 2005
    Thanks guys, I was thinking maybe the sensors might be another issue. Are they tough to replace?

    It has a 3.2 upgraded fusebox.

    Birdman
     
  5. Philjay50

    Philjay50 Formula Junior

    Jan 16, 2003
    595
    Chester, England
    Full Name:
    Philip
    #5 Philjay50, Jun 5, 2005
    They, like all things ferrari are difficult to find, if you look at the flywheel side if the engine, there are three of them,mine have a white ish wire.
    They are located at about 10 oclock 2 oclock and underneath, haha
    If my memory serves me correctly they are recessed, and held in by 2 small bolts. I would soak it all in easing fluid for a while, before attempting a change,
    There is a thread somewhere telling you how to swop the coils/ignition units around as a check, it might be worth a try, If you cannot find the thread, call and I will dig out the info for you.
     
  6. Birdman

    Birdman F1 Veteran

    Jun 20, 2003
    6,689
    North shore, MA
    Full Name:
    THE Birdman
    #6 Birdman, Jun 15, 2005
    Thought you all might like to know what it was. A bad connector at the TDC sensor for the 1-4 bank. It was intermittant. Not a very good connector design for such a critical connection!

    Birdman
     

Share This Page