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Thread: LML standalone harness

  1. #1
    Lifetime Member DURAtotheMAX's Avatar
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    Default LML standalone harness

    Im looking to make an LML bench harness...im looking at the schematics, but wondering if anyone else could check my work.

    I saw EFI Connection's LML standalone harness, but it looks like theirs only uses 2 of the 3 connectors. In looking at the schematic, it seems like the LML harness requires all 3 connectors? Or does it? Obviously if one of the connectors has an internally bonded circuit, I would rather just leave off the 3rd connector to make the bench harness less clunky.

    C1, pin 48....ignition +12v
    C1, pin 73....ignition +12v
    C1, pin 26....ignition +12v

    C1, pin 67....battery +12v

    C1, pin 46....GMLAN -
    C1, pin 66....GMLAN +

    C2, pin 17....ground
    C2, pin 18....ground
    C2, pin 21....ground
    C2, pin 73....ground

    C3, pin 73....ground

    This is EFI Connection's harness...clearly only shows 2 connectors, I cant see which two though.

    Click image for larger version. 

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    thanks
    Ben
    2005 Silverado, CC/SB, 4x4, LT, LILLY/Allison
    12.9s @ 108 mph

    many thanks to Ross and Paul

  2. #2
    Lifetime Member GMPX's Avatar
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    I only use a single connector on mine, everything you need is on the blue plug, the grounds are all internally connected so there is no need to connect the grounds on C2 and C3, just buzz them back to grounds on C1 and use those. Also, these things pull a lot of current when they first fire up!
    I no longer monitor the forum, please either post your question or create a support ticket.

  3. #3
    Lifetime Member GMC-2002-Dmax's Avatar
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    I have the EFI Live connection harness, it works fine for TIS files, Ross is correct it wants a strong power supply.

    If not the ecm will crash while flashing
    www.mscservices.net


    Tuner of many, many Duramax and Cummins Diesels.


  4. #4
    Lifetime Member DURAtotheMAX's Avatar
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    Quote Originally Posted by GMPX View Post
    I only use a single connector on mine, everything you need is on the blue plug, the grounds are all internally connected so there is no need to connect the grounds on C2 and C3, just buzz them back to grounds on C1 and use those. Also, these things pull a lot of current when they first fire up!
    Alright great thanks Ross. Ill get out my multimeter and see which pins on C1 are tied to ground, and use those.

    Ive already "bench flashed" an LML ECM, but that was with an entire full engine standalone harness on the bench. I was extremely surprised at how much current it pulls at startup as well! The in-rush was every bit of ~4 amps, according to my lab-grade bench power supply.

    Ben
    2005 Silverado, CC/SB, 4x4, LT, LILLY/Allison
    12.9s @ 108 mph

    many thanks to Ross and Paul

  5. #5
    Lifetime Member GMC-2002-Dmax's Avatar
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    I have a dual 450W-15A power supply just for these picky ecm's

    The EFi Connection does not use the BLACK connector, only the Blue and Grey
    www.mscservices.net


    Tuner of many, many Duramax and Cummins Diesels.


  6. #6
    Lifetime Member DURAtotheMAX's Avatar
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    Quote Originally Posted by GMC-2002-Dmax View Post
    I have a dual 450W-15A power supply just for these picky ecm's

    The EFi Connection does not use the BLACK connector, only the Blue and Grey
    Are you using an ATX PC power supply Tony?
    2005 Silverado, CC/SB, 4x4, LT, LILLY/Allison
    12.9s @ 108 mph

    many thanks to Ross and Paul

  7. #7
    Lifetime Member GMC-2002-Dmax's Avatar
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    Yes,

    the 2001-2010 ECMs don't pull a lot of juice, but these do.

    I have them tied together so I have enough power.

    I almost thought about getting a small battery and leaving it on a minder for enough reserve amps
    www.mscservices.net


    Tuner of many, many Duramax and Cummins Diesels.


  8. #8
    Lifetime Member GMPX's Avatar
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    Also when TIS reaches the end of the flash the ECM resets and if the power supply hasn't got enough juice TIS thinks the flash failed and it starts again.
    I no longer monitor the forum, please either post your question or create a support ticket.

  9. #9
    Lifetime Member THEFERMANATOR's Avatar
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    I'm guessing the large current draw would be the ECM charging the capacitors to fire the high voltage piezo injectors the LML uses?
    1995 GMC 2500 SUBURBAN powered by 01 DURAMAX/ALLISON, little of this, a little of that,
    DIAMONDEYE 4" exhaust, CORSA muffler, AFE stage 1 dry filter, custom tuning by me, KENNEDY single pump and pump rub kit.

  10. #10
    Lifetime Member GMPX's Avatar
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    Yes I would say so, then it detects open circuit injectors and shuts it off.
    I no longer monitor the forum, please either post your question or create a support ticket.

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