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WTB: 1994 LT1/T56 F-Body PCM

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  • WTB: 1994 LT1/T56 F-Body PCM

    Narrowed my problems down, harness is good, opti is good, connections are good, I need a new PCM.

    Anyone have a spare '94 PCM for an LT1/T56 car laying around they would like to get rid of? PM me details (price, location, etc.), and I'lll make it happen. Gotta get this fixed.
    Nick H.
    Current MIFC Vice President

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  • #2
    Good luck man, hope this fixes it.
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    U.S. Army 1983-2005
    11.20@122.37 1.51 60'

    Originally posted by WMCCjames

    "Plans Subject to change upon Sobering up"

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    • #3
      PM sent. I"ll be interested to see if this fixes it as my car has crap throttle response now and I know it's not the opti etc.
      sigpic
      Just your normal loud and slow LT1

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      • #4
        I know this car had an MSD Digital 6 in it so who knows what they did to it. Brian might be able to help and flash a stock m6 tune on for you? Just thought if you could I had a spare one laying around I could help with. (your pm box is full just FYI lol)
        sigpic
        Just your normal loud and slow LT1

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        • #5
          Originally posted by chrizar View Post
          I know this car had an MSD Digital 6 in it so who knows what they did to it. Brian might be able to help and flash a stock m6 tune on for you? Just thought if you could I had a spare one laying around I could help with. (your pm box is full just FYI lol)
          Sorry about that. I'll go through it and purge some of the older stuff.

          Contact me via email if you could. MIFirebirdClub@gmail.com
          Nick H.
          Current MIFC Vice President

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          • #6
            Originally posted by OIF1VET View Post
            Good luck man, hope this fixes it.
            Thanks. New opti went in, looked like the #3 contact on the old one was a little burnt, pulled the plug, no issues, wire looks fine. Figured it must have been a loose plug wire connection or something.

            The car runs fine, drives fine, I'm just pulling my hair out trying to fix the last VERY MINOR issue that is preventing it from being at 100% as far as the engine is concerned. It starts hard still, which is odd, because it didn't do that before we replaced the timing chain, coil, opti, water pump, etc., so I'm trying to figure out what could have happened that would cause the issue. I'm seriously leaning toward PCM at this point, as it randomly throws a DTC 16, but doesn't kill the engine at all, which indicates it's an intermittent code. Brand new opti and opti harness indicate a problem further back in the wiring, and the wires only run about 5 feet from the opti harness to the PCM, so pulling new wire, re-pinning the opti connection and PCM connector wouldn't be an issue. I just want to rule out the PCM first, since it's 2 bolts, 4 connectors, and about 10 minutes to swap.
            Nick H.
            Current MIFC Vice President

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            • #7
              After further diagnosis, it seems as if the DTC 16 is being generated BEFORE the engine is cranked. Basically, as soon as the key is turned to "on", the PCM reads a DTC 16, which resolves after cranking the engine, allowing it to start. This is either caused by A) A bad electrical connection or ground, causing a low voltage condition, B) A broken/shorted wire(s) in the ignition wiring, or C) An internal fault in the PCM. At this point, I'm leaning toward B, as we did clean up some faulty wiring in the ignition, replacing the ground terminal, and as I wasn't the one soldering the wires, the connection can't be verified at this point.

              Anyone here with a '94 or '95 car willing/able to snap a pic of the wiring at the coil on the driver's side cylinder head? Looked like one of the other wires was grounded, poor connection, so we cleaned it up, but on second thought, I don't think GM would have run redundant grounds in the same harness for the ignition. . .
              Nick H.
              Current MIFC Vice President

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              • #8
                This is what I have on my 96.

                photo copy.JPG
                1998 Chevrolet Camaro Z28 - 6 Speed

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                • #9
                  Originally posted by nascarnate326 View Post
                  This is what I have on my 96.

                  [ATTACH=CONFIG]50011[/ATTACH]
                  What colors are the wires from the harness that are grounded at the ICM stud? Hard to tell in the pic, but it looks like 2 yellow wires and a brown wire? Am I right? Would the factory wiring be changed at all to allow for the use of an MSD "Blaster" series coil? I swapped the Blaster coil out in favor of a stock replacement coil, but I don't know if the stock wiring was altered at all. . . Just trying to figure out if it's possible that the wiring is now wrong, given the coil swap. We did a lot of work to the car, and the intermittent DTC 16 started after we finished, so I'm backtracking to find out if we did something to inadvertently compromise the ignition wiring.
                  Nick H.
                  Current MIFC Vice President

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                  • #10
                    I have two yellow/white wires going into one connector, one black wire, and then the metal ground strap.

                    I dont know if the MSD is different, I kept my build all ac delco or direct replacement.
                    1998 Chevrolet Camaro Z28 - 6 Speed

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                    • #11
                      Originally posted by nascarnate326 View Post
                      I have two yellow/white wires going into one connector, one black wire, and then the metal ground strap.

                      I dont know if the MSD is different, I kept my build all ac delco or direct replacement.
                      That's what I'm trying to do with the ignition system, keep it all OEM or equivalent, but I only seem to remember two wires and the ground strap on mine being grounded there. I'll check it out further on Thursday when I return home.
                      Nick H.
                      Current MIFC Vice President

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