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Thread: blue/green PCM to red/blue PCM wiring changes?

  1. #1
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    blue/green PCM to red/blue PCM wiring changes?

    Hey guys, I swapped a 2004 LQ4 6.0L 4L80E trans setup from a 2004 Express van into my 1994 Chevy truck. its using computer service number 12583659 which uses the Green and Blue plugs. I bought this setup complete wiring, accessories, computer the whole 9 yards and the Van setup came from the factory with cable operated throttle body but no matter what I do in the programming I can't affect the idle speed. So the thing won't idle worth shit when cold and will stall darn near every time I turn the AC on as the computer seems to make no attempt to open the IAC valve to control the idle. I know this green/blue connector PCM was primarily used with drive by wire setups and so I would like to try changing my wiring to run a red/blue plug 12200411 older PCM that was used with cable operated throttle bodies to see if I can get this thing to idle correctly. Everything else I have tuned in and runs very strong but this idle is annoying. I have the throttle stop set where it idles a bit high when warm to get it to idle pretty quickly cold but still stalls nearly every time if I turn the AC on. From the looks of the wiring diagrams there appears to be some ground wires on the green plug that isn't utilized on the red plug PCM's but that appears to be about it.

    Here are my wiring diagrams.
    http://www.harrishighperformance.com/bluegreenpcm.htm

    http://www.harrishighperformance.com/blueredpcm.htm

    Any help on this wiring would be appreciated or if you have had issues with this blasted idle problem.

  2. #2
    Senior Tuner Google's Avatar
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    wiring will be determined by the operating system aka, "tune file, and or ".hpt file" you use in the pcm. eg; I have a pcm from a 2004 silv. and flash a 2001 camaro file into the pcm - I would wire the pcm for the 2001 camaro.
    We Can Fix Your Bricked PCM Or Your YYYYYY OS ID

  3. #3
    Senior Tuner Google's Avatar
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    forgot to add... if your having idle problems,,, post the current tune file and a log
    We Can Fix Your Bricked PCM Or Your YYYYYY OS ID

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    Senior Tuner Frost's Avatar
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    Quote Originally Posted by Google View Post
    wiring will be determined by the operating system aka, "tune file, and or ".hpt file" you use in the pcm. eg; I have a pcm from a 2004 silv. and flash a 2001 camaro file into the pcm - I would wire the pcm for the 2001 camaro.
    are you sure? Most of those PCMs physically don't have the IAC driver in them (native DW). Some further info on this here int he first page of the tuning section http://www.ls1tech.com/forums/pcm-di...46085-iac.html
    Steve Williams

  5. #5
    Senior Tuner Google's Avatar
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    Quote Originally Posted by Frost View Post
    are you sure? Most of those PCMs physically don't have the IAC driver in them (native DW). Some further info on this here int he first page of the tuning section http://www.ls1tech.com/forums/pcm-di...46085-iac.html

    Thanks Steve! I have not run into this before.. Guess I have been lucky on my swaps..


    Quote Originally Posted by Link Above
    1999 to 2002 all PCM's support IAC
    2003+
    SERV. NO. - HWD NO.
    12576106 - 12570558 - 2003 G-VAN, LM7, IAC DRIVERS. C1500 LM7
    12586243 - 12583659 - 2004 GTO LS1, IAC DRIVERS
    12589462 - 12589161 - 2005 G-VAN, LQ4, IAC DRIVERS
    12602801 - 12589161 - 2006 - 2007 Express, Drive by Wire, (has IAC drivers)


    2004
    Silverado PCM, DOES NOT WORK with cable throttle:
    Serv. No. 12586242
    Hwd. No. 12593660

    2005 & 2006
    Silverado PCM, DOES NOT WORK with cable throttle:
    Serv. No. 12589463
    Hwd. No. 12589162
    We Can Fix Your Bricked PCM Or Your YYYYYY OS ID

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    I heard about the IAC driver but I do know that the original wiring was green/blue connector and has the IAC and TPS are wired into the main harness but I do have a idle problem that could be explained by that IAC driver issue which is why I would like to try a red/blue connector PCM. I just want to make sure that I change the right pins so I don't fry the new pcm or cause myself another issue that i have to figure out.

  7. #7
    Senior Tuner Google's Avatar
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    Quote Originally Posted by brharris27317 View Post
    I heard about the IAC driver but I do know that the original wiring was green/blue connector and has the IAC and TPS are wired into the main harness but I do have a idle problem that could be explained by that IAC driver issue which is why I would like to try a red/blue connector PCM. I just want to make sure that I change the right pins so I don't fry the new pcm or cause myself another issue that i have to figure out.

    From the information that Frost pointed to, your pcm has iac drivers and you prolly just need to tune idle..

    post your tune and a log.
    We Can Fix Your Bricked PCM Or Your YYYYYY OS ID

  8. #8
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    the thing is my spark plug coloring is fine and it will idle just fine if I hold my foot on the throttle and manually control the idle and my long term fuel trims are 0-3% at idle and I don't care if I set the chip to 3000 rpms for idle it never changes anything and I have the programming set for cable throttle body and not electronic throttle. Its a conundrum which is why I want to change computers as I have plenty of pcms and if the wiring changes are as easy as it appears then I shouldn't have a problem and so I wondered who has done it and how hard was it.