Fuel delivery system

Asked by GuruTRP8C Jul 15, 2018 at 12:32 PM about the 1991 GMC Sierra 1500 C1500 Extended Cab LB

Question type: Maintenance & Repair

I have a 1991 GMC Sierra that is
having fuel delivery problems.
It'll start fine and run fine until it
warms up, then it seems like the
fuel pump quits working. I've
watched the see through fuel
filter that is close to the
carberator to see if in fact it is a
fuel delivery, and it is in fact a
fuel issue because the filter is
sucked dry by the carb and the
fuel pump seems to quit
pumping, but this is only when
the motor is warmed up

1 Answer

26,640

How long since a tune-up? Any applicable trouble codes? With tbi fuel system the fuel pressure, 9--13 psi, use a fuel gage to check pressure. Also with tbi fuel injection you can usually see fuel injector spray pattern, engine cranking. I have to say I have seen fuel injector spray patterns that looked good to me, but, the fuel pressure was half of what it should have been, so a nice looking spray pattern is not conclusive. So, when problem is ongoing check good voltage and ground for fuel pump, if good and no fuel pressure, suspect the pump.

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