Question about GMC Sierra 1500

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My 1993 GMC Sierra Z71 will not start. We changed the fuel pump, the throttle pressure regulator, fuel filter,and fuel pump relay. The pump gets gas to the injectors but from there it does nothing and goes nowhere. We scanned the computer and it didn't give any problem codes. We also checked fuel line pressure and it seems ok. Could the trucks computer be telling the injectors not to spray?

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  • Jeremy W.
    Jeremy W. Mar 26, 2011

    Do you have power to the injectors?

    Have you checked for injector pulse?

    Do you have spark?

    What Motor?

  • aalata01 Mar 26, 2011

    We have power to the injectors, and spark. It's a 5.7 V8. Fuel reaches the TBI unit but something is keeping the injectors from squirting the fuel farther into the engine.

  • Jeremy W.
    Jeremy W. Mar 26, 2011

    Whats the resistance of the injectors?

  • aalata01 Mar 27, 2011

    The injectors get power we are sure of that. WE are now thinking that the EPROM chip isn't working. How does this operate and could it be the source of the problem?



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Hi, that's possible but first check the ECM fuse and use a test light to check for power to the injectors on the red and white wires. The computer uses a number of sensor inputs to calculate the injector signals required. If these signals are not available, the computer cannot send the appropriate injection metering signal and will usually set the engine light. Is the engine light on?

my 1993 GMC Sierra Z71 - jturcotte_1332.gif


Posted on Mar 27, 2011

  • Jeffrey Turcotte
    Jeffrey Turcotte Mar 28, 2011

    Sorry, have you figured this out yet? Is the EPROM one of those add-on performance chips, or is that a stock part? If stack, I don't know what part you're talking about. If add-on, I would take it out until you get the truck running again.

  • aalata01 Mar 28, 2011

    I don't know if the chip was stock or aftermarket. It said AC Delco on it which led me to believe it was stock, but the dealer said it was discontinued and that the numbers on mine didn't match what he was showing as being stock for that truck. After a week of having it down and $250 into it without any results, I gave up and had it towed to the shop.



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