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  1. #1

    Default Wiring info needed

    Ok I’m swapping a first gen small block into my 1999 s10 ls. This truck came as a 2.2 and automatic transmission. I’m in need of some help with the wiring. I want to remove the ecm and efi harness. I still need the truck to start from the key and the headlights/taillights work on the truck.

    I added a photo of a plug in the harness that i need help with.
    This plug hook's in to the ecm/efi harness what all does it work in the truck? This harness also runs back to the relay center under the hood on the ecm side.

    All help is welcome thanks.

    Click image for larger version. 

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    Last edited by Quad racer#212; 06-18-2012 at 06:51 PM.
    2000 Ls s10 V8 extended cab drag truck
    1999 s10 Ls Droped 2.2L
    1998 s10 blazer red stock

    1985 s10 blazer 5 speed v8
    1982 4X4 355ci 450hp k1500 trail truck
    1978 4x4 short bed F150 460ci 540hp mud truck on 38.5 super swampers boggers

  2. #2
    Sr. Engineer
    Join Date
    Oct 2010
    Indianapolis, In


    Not to clear about what you are trying to do. Do you want to remove all traces of the original EFI and ECM wiring? Have you already swaped the motor and it now works without the computer? Is the first gen a carburated motor?
    2000 GMC YUKON SLT, 5.3L tow pkg, G80 rear/w 3.73 gear

  3. #3


    Looking in the haynes or chilton manual at the wiring diagrams should give you an idea as to what is what in that harness. It won't straight-up give you the pinouts from that connector, but the colors of wires going to the ecm should be unique for each wire. So, look at different devices you know you don't have or need, and look at the wire color indicated in the diagram, and see if that color wire's in there. If so, it's probably pretty safe to pull.
    Last edited by Crawdaddy; 06-19-2012 at 08:20 AM.

    1991 Chevy Suburban 1/2 ton 2WD w/ chevy SBC 350-3/4 ton drivetrain upgrade w/4.10 gears 200K miles
    2005 Saturn ION-2 Stock 277K miles
    1982 Bronco, 1993 Bronco (sold), 1971 M35A2 Deuce and a Half

    There are 10 kinds of people, those who understand binary, and those who dont...

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  4. #4


    @dpeter Yes i will be using a carburetor. Yes the motor is in the truck. Yes i want to remove all traces of the original EFI and ECM wiring. i still need the headlights and tail lights to work and the truck to start using the ignition switch.

  5. #5
    Sr. Engineer
    Join Date
    Oct 2010
    Indianapolis, In


    Crawdaddy has given the best advice I can think of. You have a tedious job ahead of you and best of luck with it.

  6. #6


    I have changed my mind on sticking a carbureted small block in my truck. I came up with a lq9 6.0 for the low low turbo time

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