fuel pump problems 93 sierra

i have a 93 5.7 engine sierra and changed the fuel pump two times and the pump keeps shutting down. all connections are good, new relay, new oil pressure switch, grounds are also good . can any body shed any light? , short of repalcing the whole truck to fix the problem, i don't know what else to check :banghead:

The computer controls the fuel pump. If it does not see the engine start it will shut off the pump. When you turm the key to on it will run the pump for about 2 seconds and shut off until you crank. When does the pump shut off ?

the engine will run for about 5 to 10 minuites before it shuts down. some times it will start right back up sometimes i have to wait. i have checked voltage while running and the voltage is there for about two seconds after it shuts down

You have'nt had any tranny work done since this problem started have you?

Put a guage on the fuel line and a voltmeter on the pump. Watch when the engine shuts off. Do you have voltage and pressure ? Which one stops first ? Or could something be shuting off first ?

If your truck has a connector on top of the tank,(outside) look close at the pins inside it.
They corrode and burn then give this symptom.

thanks, i'll check everything. had tranny rebuilt about 1 1/2 years ago the problem started about 2 months ago.