94 GMC Sonoma fuel problem


Asked by Jan 29, 2017 at 06:37 PM about the 1994 GMC Sonoma 2 Dr SLS Standard Cab SB

Question type: Maintenance & Repair

I have a 94 GMC Sonoma with a 4.3 TBI.
When I turn the key on the fuel pump doesn't
prime. It is not getting a signal from ECM to
relay. There is a test wire under the hood I
can hook to the battery and the fuel pump
comes on but then the injector won't come
on so I can spray starting fluid in the throttle
body and they will come on and the truck
will stay running and I can unplug the test
wire to fuel pump and the fuel pump stays
on. I have changed ECM and relay in the
dash still the same problem.

4 Answers


so after priming the fuel with a jump wire you still have to dump starting fluid to get it to run , trace the circuit back , maybe it's goes through a pressure sensor , you should test the injector to see whether it's working or not and some motors need a correct fuel pressure to run not a "charge " if it was fun everyone would do it


I plugged a noid light into the injector and it wasn't pulsing. I have changed the fuel pump twice since this has started happening if I start it and run it like that the fuel pump will burn up after a couple months in my manual it says the relay is only for starting then the relay turns off and it runs off of the oil pressure. I haven't been able to find a diagram online.and is the oil pressure sending unit the oil pressure switch

1 of 1 people found this helpful.

I changed the oil pressure switch still having same problem does anyone have any other ideas


if that injector is not pulsing I'd say that is your problem

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