PCM/Wiring harness ???

Discussion in 'High Tech Retrofits' started by purpleflame, May 7, 2008.

  1. purpleflame

    purpleflame Veteran Member

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    Can I just use the harness and PCM from the car the motor came out of, or buy a harness from someone and who? which is easier to install???
     
  2. GetMore

    GetMore Veteran Member Lifetime Gold Member

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    From what I've seen (80's EFI systems) the PCM harness goes to the EFI system and maybe the transmission. There will also be a power and ground connection, but that's about it.

    In those instances it is easy to use the harness from the car.

    If you need to disable certain features (VATS, O2s, EGR, whatever) you will need to modify the harness, and at this point it may become easier to buy an aftermarket one. Painless is one source, but there are a few others. I can't think of their names and don't know who is good or bad.
     
  3. purpleflame

    purpleflame Veteran Member

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    this is a 95 firebird PCM bought the car for motor and trans and am wondering if the stock harness although not as pretty as a painless will work fine? I know i'll have to connect everything up but am using quite a bit of the 95 on my 72,fans,o2's,maf,and evry other function that relates to the engine.
     
  4. 3_z28camaro

    3_z28camaro Veteran Member Lifetime Gold Member

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    The PCM will have to be reprogrammed regardless, the wiring harness will either have to be modified or replaced with one by Painless.

    For my LT1 swap I had this guy do the wiring and PCM, about the only things I cannot do myself.

    http://www.pcmamerica.com/

    I have not installed the engine and transmission yet so I do not know how good of a job this guy did. If I were to do another swap in the future I might try somebody else just to see how they do.
     
  5. nobreaks254

    nobreaks254 Veteran Member

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    Do the research and mod the stock harness yourself. At least then when something goes wrong you have a clue. Call around and find someone you trust to do your PCM work for you.
     
  6. BonzoHansen

    BonzoHansen Administrator Lifetime Gold Member

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    If you do this, scour ebay for factory service manuals for the donor car.
     
  7. ULTM8Z

    ULTM8Z Veteran Member

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    I'd just go with a Painless harness. The quality is excellent.
     
  8. purpleflame

    purpleflame Veteran Member

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    Thanks guys, I have done a lot of research and feel pretty comfortable doing the swap I am pretty good at wiring and pretty much understand how all this works, as for my pcm it has a pcmforless tune in it done by brian herter he has a pretty close set up as mine, so will probably need to do a tune when done cause some things are gonna change, no opti going with a distributor, but gonna run all the dual fan and relays and sensors for the fans. Im assuming you can run a distributor over the OPti my lt4 intake is drilled for it and the block has everything in it for a distributor. this motor is a monster, lt1 stroked to a 396 with all forged internals and AFR 227cc heads ported and polished,LT4 intake with 42lb injectors, and a monoblade TB 1300cfm. comp cams ,263,268 dur./ .628,.638 lift, its a custom grind from them. any one running a familiar setup???
     
  9. John Wright

    John Wright Veteran Member Lifetime Gold Member

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    Last edited: May 8, 2008

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