no pulse to injectors

Discussion in 'Technical Discussions' started by Roy Lee Patterson, Jan 30, 2021.

  1. Roy Lee Patterson

    Roy Lee Patterson New Member

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    Dec 5, 2017
    1995 Tahoe 5.7 auto 4x4 TBI
    I have a start but will not run issue. I have checked everything and I am not getting the signal from the ECM that fires the injectors via ground. I have twelve volts at the injector and I have good ground engine to chassis.
    I don't have a manual on hand for the early Chevy's so.
    What I need to know is how to find the wires (which wires at the electrical connecter) on the ECM to check the ground which the ECM uses to fire the injectors.
    The engine cranks, I have signal then signal stops and engine dies, all grounds are good, double checked and replaced fuses etc. Replaced the ICM in the distributer several times and I have switched out the ECM for the specific model.
    So which wires on the ECM harness run the injectors?
    Searched for and found the PCM/ECM connector diagram, took a while. Here's the link
    https://troubleshootmyvehicle.com/gm/4.3L-5.0L-5.7L/ecm-pin-out-chart-1

    Too late in the day to do anything more so in the am, I am going to check that the PCM has good grounds.
    I just put the engine back into the Tahoe, I know I have engine to battery ground but I wonder now about the engine to chassis ground, it maybe a painted surface issue, I don't know, it's below freezing out there now so I am going to try and stop wondering.
     
    Last edited: Jan 30, 2021