83 512BBi wiring diagram | FerrariChat

83 512BBi wiring diagram

Discussion in 'Boxers/TR/M' started by Bertocchi, Aug 8, 2016.

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  1. Bertocchi

    Bertocchi Formula 3
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    Jan 28, 2004
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    David Castelhano
    #1 Bertocchi, Aug 8, 2016
    I am troubleshooting an issue with the fuel pump relays in an 83 512BBi. The wiring diagram I am using was printed in 81 and I am finding differences between the diagram and what is actually in the car. Has anyone else come across this?
    I know the intake systems on 81/82 are slightly different than 83/84 and can't believe that anyone would have modified the relay panel.
     
  2. turbo-joe

    turbo-joe F1 Veteran

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    romano schwabel
    #2 turbo-joe, Aug 8, 2016
    what problem you have?
    may be one here can help?
     
  3. Bertocchi

    Bertocchi Formula 3
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    #3 Bertocchi, Aug 8, 2016
    First of all I never saw this car run prior to being delivered to me. It sat for nearly ten years.

    1) The engine was removed and a major belt service was performed...everything. Valve adjustment, cam timing with a degree wheel and checking clearances, and water pump rebuild.
    2) The warm up regulators and fuel distributors have been redone by CIS Flowtech.
    3) The Gas tanks came out and were flushed and reinstalled.
    4) A new ignition switch and both fuel pumps were replaced by the owner.
    5) The car wants to start but only has fuel pressure on the left bank so it struggles.
    6) When the Right side fuel pump relay is jumped the car starts but won't idle. The is no signal to the warm up regulators or the aux air valves (same circuit).
    7) The wiring to the relays does not coincide with the Schematic from the 81 owner's manual. the grounds and supplies are reversed.

    When the car gets warm it runs beautifully but the throttle has to be held open by hand.
     
  4. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    #4 Steve Magnusson, Aug 8, 2016
    This is not unusual IME -- often the wires going to terminals 85 and 86 can be swapped for reality vs what's on the schematic, and same for what's connected to terminals 30 and 87 on a ...113 relay as there's no functional difference.

    IIRC, on the F K-Jet models, the +12V power for the AAV and WUR heaters just comes from the same place that is supplying +12V to the fuel pump (for that bank). Don't have access to a BBi schematic at the moment, but will have a look tonight...

    IIRC, the fuse block for the fuel pump fuses is a trouble spot on BBi -- any signs of molestation/modification/rewiring in that area?
     
  5. Bertocchi

    Bertocchi Formula 3
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    #5 Bertocchi, Aug 10, 2016
    Steve, you nailed it. 85 and 86 are switched but many of the relays are linked. They share common grounds and +12V feeds with other systems. I am wondering if I am getting feedback some how or there is a bad ground somewhere?
    I have been "ohmming" out every circuit and they all ring true.
    I find it odd though that the fuel cut off (safety) switch shares a ground with the rear fog lights.
     
  6. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    #6 Steve Magnusson, Aug 10, 2016
    The schematic indicates that, at each fuel pump relay, there is one terminal (either 30 or 87) that has two wires swagged into the same metal female terminal (two P beige or two PN beige-black) -- one of those wires goes to the fuel pump for that bank, and the other wire goes to the AAV and WUR for that bank.

    You indicate that you are able to "jump" the right side fuel pump relay to get that fuel pump to run, but have no +12V power at the AAV and WUR for that bank -- is that correct? (And one warning I'd give here is that "left" and "right" can sometimes mean different things so be careful about assuming if something labeled "right" actual is something for what you would think is for the right bank). One thing I'd recommend is making three measurements at each AAV and WUR when you think it should have +12V power present:

    1. DC voltage between the two terminals in the harness connector,
    2. DC voltage between one of the terminals in the harness connector and the engine block,
    3. DC voltage between the other terminal in the harness connector and the engine block.

    From these measurements you can sort out whether +12V is not getting there, or if there is a bad ground.

    It won't help the two runability issues that you mention (1. won't start and run cold, and 2. warm it runs beautifully but the throttle has to be held open by hand), but it would have to be a very subtle problem (like a bad swage or a broken wire) to have a fuel pump running and not have +12V power present at the corresponding AAV and WUR (unless things have been modified).
     
  7. Bertocchi

    Bertocchi Formula 3
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    #7 Bertocchi, Aug 26, 2016
    Thank you Steve and Paul for your help. I discovered the car had a faulty Cold start relay. The main fuel pump relay shares a white/black wire with the cold start and since the cold start was bad the main would not function correctly.
    I can not find new Bosch relays with metal covers or I would replace them all.
     
  8. Newman

    Newman F1 World Champ
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    #8 Newman, Aug 26, 2016
    Because the relays are well hidden I wouldn't worry about metal vs black plastic relays if it means less problems down the road.
     

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