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Thread: Pin questions for '7747 prior to installation

  1. #1
    Fuel Injected!
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    Pin questions for '7747 prior to installation

    Forgive me for forgetting my notes and posting based on memory. I am in the process of cleaning up my harness and want to figure out a couple of things. It's going in a 4x4 crawler.

    First, pin B8 for the AC signal. What does this do exactly and does it expect 12v or ground? I assume it raises RPM which I could use for winching. It would be worth adding a switch in my dash if it does raise the RPM. Would the switch supply ground or 12v?

    Second, the ALDL wires. The pinout of the ALDL doesn't match anything I have found. The positions are all wrong. I assume I can swap pin positions (haven't tried). What bothers me is that A5 for the SES light terminates in the ALDL connector. Surely this isn't correct or did the early computers do this?

    Thanks,

    Steve

  2. #2
    Fuel Injected! mmigacz's Avatar
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    Second, the ALDL wires. The pinout of the ALDL doesn't match anything I have found. The positions are all wrong. I assume I can swap pin positions (haven't tried). What bothers me is that A5 for the SES light terminates in the ALDL connector. Surely this isn't correct or did the early computers do this?

    Thanks,



    Below should help with wiring the ALDL

    ALDL.jpg
    1986 ski centurion boat, 351W, gt40P heads, edelbrock performer rpm, 1227747 ecm, 72 lb/hr injectors (@18 PSI fuel pressure), .490/.490 lift, intake 278 duration, exhuast 282 duration, 112 lobe separation

    1969 camaro, 355ci, performer RPM intake, camel hump heads, 1227747 ecm, 454 throttle body (@18 PSI fuel pressure),

    2016 Chevy Cruz

    2014 Chevy Silverado

  3. #3
    Fuel Injected!
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    I will have to verify tonight, but this image does show the SES wire going to the ALDL port. Can I just run a wire from that pin to a dash light (12v at the light and the SES pin being the ground)?

    Quote Originally Posted by mmigacz View Post
    Second, the ALDL wires. The pinout of the ALDL doesn't match anything I have found. The positions are all wrong. I assume I can swap pin positions (haven't tried). What bothers me is that A5 for the SES light terminates in the ALDL connector. Surely this isn't correct or did the early computers do this?

    Thanks,



    Below should help with wiring the ALDL

    ALDL.jpg

  4. #4
    RIP EagleMark's Avatar
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    You only need three wires to ALDL port as shown in this diagram.
    http://www.gearhead-efi.com/Fuel-Inj...5&d=1331599707

    For the SES/CEL you need 12 volt to light and the other to A5 at ECM is the ground
    http://www.gearhead-efi.com/Fuel-Inj...7&d=1331599707

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

  5. #5
    Fuel Injected! mmigacz's Avatar
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    Whoops, I had an error.

    ALDL.JPG
    1986 ski centurion boat, 351W, gt40P heads, edelbrock performer rpm, 1227747 ecm, 72 lb/hr injectors (@18 PSI fuel pressure), .490/.490 lift, intake 278 duration, exhuast 282 duration, 112 lobe separation

    1969 camaro, 355ci, performer RPM intake, camel hump heads, 1227747 ecm, 454 throttle body (@18 PSI fuel pressure),

    2016 Chevy Cruz

    2014 Chevy Silverado

  6. #6
    Fuel Injected!
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    I reviewed my ALDL and the pin positions do not match either drawing. I'll have to resolve that. Thanks.

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