HELP! 1995 F355 1-4 bank not working | FerrariChat
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HELP! 1995 F355 1-4 bank not working

Discussion in 'Technical Q&A' started by tim355, Sep 30, 2004.

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  1. tim355

    tim355 Karting

    Nov 7, 2003
    57
    #1 tim355, Sep 30, 2004
    I was driving home from Seattle about a month ago and all of a sudden I lost my 1-4 bank. I pulled off to the side of the road, re-started the car, no help. As I was limping the car home everything started working again. (no "check engine" lights came on). This happened one additional time. Now it seems that the 1-4 bank is completely dead. I figured it was the ECU so I swapped ECU's from the 5-8 bank with the 1-4 bank, still no help. The 5-8 runs fine but the 1-4 is still dead. I swapped all the relays and fuses under the passenger footrest (ECU 1-4, RH fuel injectors, RH fuel pump), still no help. I do notice that with the key in the on position that the 5-8 idle motor is running but not on the 1-4 side. Is almost seems like I have a grounding problem or a short. I don't have a copy of the wiring diagram manual to trace the ground wire back for the RH wire harness. Any ideas where this is at? Should I pull a spark plug wire off and check for spark? I suppose this would narrow it down to spark vs fuel? Any ideas?
     
  2. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,932
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #2 Steve Magnusson, Sep 30, 2004
    When you say that you "swapped ECUs" does that mean you swapped the ECUs actually running the injection systems or the over-temp warning light ECUs?

    Definitely check for spark presence/absence on each bank as a first decision maker (but using a timing light would be safer).

    Do you have cats?

    Your report of unequal electrical behavior of the other associated components is a sign towards something's gone wrong in the upstream power supply stuff (either +12V or ground), but I don't have that model's wiring diagram so can't say anything specific. Can you measure/compare the voltages on the wires at the injection ECUs when they are plugged in and operating? Or how about at those "idle motor" connectors -- e.g., if a +12V signal is always present (when "on") at one of the wires for one side, but not at the other, that would be a strong clue.
     
  3. tim355

    tim355 Karting

    Nov 7, 2003
    57
    #3 tim355, Sep 30, 2004
    I swapped the ECU's that are under the 2 side wings in the engine compartment. The R/H one is near battery connection cables.
     
  4. tim355

    tim355 Karting

    Nov 7, 2003
    57
    #4 tim355, Sep 30, 2004
    I have my cats installed. The ECU's are computer type boxes 8" X 8" X 2".
     
  5. tim355

    tim355 Karting

    Nov 7, 2003
    57
    #5 tim355, Sep 30, 2004
    My problem is definitely electrical. When the ignition key is turned on I don't even get the orange Check engine light for bank 1-4.
     
  6. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,932
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #6 Steve Magnusson, Sep 30, 2004
    Yeah, that's a clue ;) Sounds like you are going to have to get a wiring diagram to look further at the primary power supply side of things.

    How about the 1-4 over-temp warning light -- is that self-test working correctly? Not that it necessarily has anything to do with your problem, but just curious. Since you "limped" it along (from a warm condition) without the cat overheating that's another clue that the fuel side was dead (regardless of whether the ignition for that bank was dead or not).
     
  7. tim355

    tim355 Karting

    Nov 7, 2003
    57
    #7 tim355, Oct 1, 2004
    no 1-4 overtemp light
     
  8. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,932
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #8 Steve Magnusson, Oct 1, 2004
    That could be another sign that you've lost power (or ground) to that whole side somehow. If you swap the warning light ECUs, (wrongly IMO) called "catalytic converter control units" in your OM (they are the smaller units located near the injection ECUs per the OM), and you've still got the condition of 5-8 self-test OK and 1-4 self-test bad, that would confirm that they are not the problem.

    You didn't really answer my previous question about being able to measure some voltages -- my guess would be that (even when unplugged), with the ignition key "on", at least one of the wires going to each warning light ECU would measure +12V (relative to the chassis ground) -- if you get something on the 5-8 side and nothing on the 1-4 side that would confirm an upstream power problem.
     
  9. tim355

    tim355 Karting

    Nov 7, 2003
    57
    #9 tim355, Oct 1, 2004
    Yep the catalytic converter control units (warning light ecu's) are actually attached to the same bracket as the ECU's. So when I swapped the ECU's they got swapped in the process. I haven't measured power yet, I guess that is my next step.
     

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