No fuel from injectors 1992 5.7 vortec GMC P3500 stepvan

Asked by May 05, 2017 at 10:34 AM

Question type: Maintenance & Repair

Hi all I have a 1992 GMC with a 5.7 Vortec motor. I
have done a full tune-up on it replacing plugs wires
cap and rotor but I did not replace the distributor
itself or the ignition coil pack. It runs fine once it's
started. But it will only start with starting fluid
however last night when I spray starting fluid into
the throttle body it caught on fire and I put it out
with a fire extinguisher. This morning I cleaned up
all the dry chemical from the fire extinguisher and
now I am getting no fuel at the injector into the
throttle body. I do have an access panel so I don't
have to drop the tank to replace the fuel pump
assembly however I can't get the three bolts out
because they are rusted in. My question is does
this sound like the fuel pump assembly or and
injector problem? I have not tested the fuel
pressure because I don't see a fuel rail with a
Schrader valve and I don't have a guage.  Any input
will help immensely because this is my source of
income as it is my food truck and I need to get
back on the road ASAP

3 Answers

75,515

Yes, this is a fuel issue. You probably burnt up the connectors to the fuel injectors, just will have to get that back in order. It could be the fuel pump, or the fuel regulator in the TBI needing to be replaced. Wouldn't hurt to do both as I am sure that regulator spring is weak from years gone by and not able to create enough fuel pressure for the injectors. To check fuel pressure you need a fuel pressure gauge set up to check on a TBI system. All it does is connect in the incoming gas line and then to the TBI. Fuel pressure should be 9 to 13 lbs.

1 of 1 people found this helpful.

Thanks for the info but by the time i saw ur reply I had already replaced the pump, the whole assembly unit, and the relay. I had power at the pump, properly grounded so all good there, did an old school trick with a paperclip and got code 54...pulled the relay and sure enough totally corroded. Replaced the relay, bam, she fired right up, fine beautiful mist coming from both injectors into throttle body... all my nails are broken and greased up but my truck is running.;-) only problem remaining is the fuel filter. I bought a new 1 along with the pump etc however I was stripping 1 of the bolts trying to get the old 1 off so I ended up leaving it.

75,515

The fuel filter definitely should be changed. If you can not get it, they make sections of replacement lines for this area of the fuel line. May have to cut it out, and if you use line wrenches would be better for cracking the lines open. You would only need the on line wrench for the nut on the fuel line.

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