1999 Fuel Pump Issue

[MBMaxwell99]

I have a 5.7 Vortec and the Fuel pressure reads about 58 when I try to start it. It drops almost to zero after a few minutes. It tries to start but sounds like it is choking it self. This would be my third fuel pump in this vehicle in almost as many years. Also the fuel gauge jumps from empty to full when you start it. I think that might just be the ground. Is this an ongoing issue with fuel pumps with GM.

[maxwedge]

Maybe, maybe not, the fuel pressure regulator/spider ass'y was also problematic, just about all of these have been replaced. A loss of FP usually is traced to leaking injector lines or the regulator, the removal of the upper intake will reveal any fuel leak when pressurized. You could try pinching off the fp return line and see if the pressure still drops, that points to the pump.

[Blue Bowtie]

I've also found that the electrical connections in the circuit are problematic. There is an electrical connector near the front of the LR wheel opening which supplies power to the pump and connects the fuel gauge sender. This connector can be exposed to road spray and potential moisture intrusion. There is also a ground connection about 10" away from this connector which provides the ground for the pump. I have found both defective, as well as the connector on top of the tank.

Voltage should be tested at the pump whenever possible to provide an accurate reading. These pumps are very sensitive to voltage. If you can increase the system voltage to something closer to 15V (by jumping to a running vehicle or via a charger) and the fuel pressure then builds to a proper level, there may be a connection issue. Be careful to keep voltage below 17V (primarily for protection of the PCM).

[MT-2500]

Are you using the good AC-Delco/delphi fuel pumps?
Is the fuel filter staying good and clean?
Also running out of or real low on gas is hard on fuel pumps.