I have an 87 Z-28, 305 TPI. fuel pump wasn't working so I replaced it. it ran ok for a couple hours then the pump sounded bad so I replaced it again with an ac delco pump. the new pump sounds ok but it wouldn't stay running and my fuel pressure was only up to 15 lbs. I changed the fuel pump relay, fuel pressure regulator and fuel filter. after changing the regulator a while ago the pressure goes up to 10 lbs. while the pump energizes then drops to zero when the pump stops energizing. I checked for any fuel leaks and can't find any. is there something I overlooked? what's going on with my car? any help will be greatly appreciated. thanks

 

is the pump getting a full 12 volts of power. check that. if you get under your car and look up above the rearend you will see a plug with 2 wires going into it. the plug is fastened to the body of the car. just unplug it and put a multimeter to it. check to see if it drops as you turn the key foward

 

1st make sure the guy at the parts house didn't give you a carb fuel pump. 2nd with a pressure gauge connected, take a pair of pliars and clamp the fuel return hose. Pressure should jump up immediately. 3rd get a Walbro fuel pump