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ECUs...

Discussion in 'Technical Q&A' started by enilkram, Dec 6, 2005.

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  1. enilkram

    enilkram Rookie

    Nov 28, 2005
    5
    #1 enilkram, Dec 6, 2005
    I have this 1985 308QV...the problem is after the engine started one of the banks (Outer Banks) cut off and stop running but the engine still running with one banks... i already try to switching the coils. Nothing wrong with the distributer and rotor because i just replace it with the new one.... I've also checked the connection of the ECUs and try swaping them but still the outer banks will cut off after a while...I've checked the ECUs and found out it has different serial number in it.. are there suppose to be the same???.... Pls anyone help me with this...
     
  2. Verell

    Verell F1 Veteran
    Consultant Owner

    May 5, 2001
    7,022
    Groton, MA
    Full Name:
    Verell Boaen
    #2 Verell, Dec 7, 2005
    If the same bank is cutting out after you've switched the ECUS, then most likely it's the sensor that detects flywheel teeth going past & sends pulses to the ECU. Could just be a corroded connection to the sensor.
     
  3. Mark 328

    Mark 328 Formula Junior

    Nov 6, 2003
    510
    Orange, Ca
    Full Name:
    Mark Foley
    #3 Mark 328, Dec 7, 2005
    I had similar problems and it was caused by the connector to the transistor on top of the coils. This is a low voltage plug and you can wiggle it around while the car is running--I think in one case I even completly unplugged it. When it was unplugged the bank would not work, but there seemed to be no ill effects for having it unplugged.
    The wire harness going to the plug is heavy and stiff--if if is not placed in the exact right spot there will be too much strain on the plug and it will not make a good connection to the transistor.
    Does the 85 QV have the test plug in the sail panel? There are some pins there that connect right to the coils--it would tell if the coil is getting power and it will tell if the ground is working to complete the circuit. You can hook a tachometer there to test RPM for each coil.
    I'm at work and don't have the test plug diagram with me, but I just posted the on for the 328 a week or so ago. If you have the round plug let me know and I'll re-post the diagram I made for the 328.

    Mark
     
  4. Verell

    Verell F1 Veteran
    Consultant Owner

    May 5, 2001
    7,022
    Groton, MA
    Full Name:
    Verell Boaen
    #4 Verell, Dec 7, 2005
    My '82 Euro QV has the round plug, so I expect enilkram's '85 does also.
     
  5. Mark 328

    Mark 328 Formula Junior

    Nov 6, 2003
    510
    Orange, Ca
    Full Name:
    Mark Foley
    #5 Mark 328, Dec 7, 2005
    Last edited by a moderator: Sep 7, 2017
  6. bshaw

    bshaw Karting

    Nov 3, 2003
    65
    Connecticut
    Full Name:
    Bill
    #6 bshaw, Dec 7, 2005
    You should also check from the Digiplex connector. Take an ohmmeter and look at the TDC sensor pins, this will check all the connections from the ECU to the sensor. You should see 650 to 850 (ish) ohms. I found one cruddy connector (the bulkhead connector near the coils) this way.

    Newly replaced rotors can be a problem. There were some that are too long floating around. I bought some and they smashed on the terminals inside the cap, so you can't rule out problems there just because the rotors are new.

    Bill
     

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