GMC Sierra not running with new parts


Asked by May 10, 2016 at 08:52 PM about the 1992 GMC Sierra 1500 C1500 SLX Standard Cab SB

Question type: Maintenance & Repair

I have a 1992 GMC Sierra 1500 with the 4.3 L V6. Just bought all new
distributor cap, distributor rotor, plugs and wires, Fuel pump and fuel filter.
The truck ran great before but bought parts to pass emissions testing. All new
parts are correctly in place, but not getting fuel to the carb. When I turn it over
to start it will run if we funnel fuel into carb. So there is a spark. Not sure why
it would get fuel to the carb before, but now with new parts it's not.

5 Answers


sounds like the fuel pump is not working, fuse? relay? Should be able to hear the pump run for a couple of seconds when key is turned on.


Is the fuel pump functioning? check for fuel pump pressure and inspect all the wiring you handled. 1992 4.3 shouldn't have a carb.. must be TBI throttle body injection.


I agree with the above comments, check for battery voltage briefly at the fuel pump when you first turn on the key, double check your work at the fuel pump, there is a known failure of the fuel pump connector on these, so if the connector is good and you have proper voltage and ground to the pump then your new pump is defective unless you forgot to plug it in at the small harness inside the fuel tank. I've seen it happen.


Does have carb, and I hear the pump functioning once I turn the key


Good, so at least it is running, so now you need to check the pressure and flow, and as you have an electric fuel pump in the tank you don't have a carb it is throttle body injection, you will see two big injectors if you take the air cleaner assembly off, so the next phase is to check for injector power and a trigger signal, that can be done with a plain test light unplug the injectors, one wire will have power with the key on and the other will not on both injectors, if no power look for a blown injection fuse, then put the test light between the two power and trigger wire or the wire with no,power and crank the engine, look for a pulsing light, if it pluses then then you have everything to make the injectors fire, if they are not then you either don't have any pressure in the body or the injectors are bad. HTH

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