78 Chevy Luv Pickup / Electric Fuel Pump

Old 12-22-04, 12:26 PM
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78 Chevy Luv Pickup / Electric Fuel Pump

Have electric fuel pump on 78 Chevy Luv Pickup. Have replaced Alternator, Battery, Coil, Resistor, 2 Relays and Regulator. Truck will start just fine. Fuel pump will be pumping and then quit. Unplug regulator and plug back in and fuel pump will start pumping again. A few minutes later, pump quits pumping. Repeat with regulator and begins pumping. Have pulled wiring harness apart and traced each wire for a short to no avail. Any suggestions on what might be causing this problem. Only thing we have not done is changed fuel pump.
Old 12-22-04, 09:03 PM
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Check for voltage at the fuel pump relay, then you'll know which way to go with this. If you're losing voltage at the relay, the problem could be traced to the ignition switch. A little while back, someone wrote about a fuse that would open up when it got hot so you could check for that.

Are you sure the fuel pump is cutting off rather that some debris in the gas clogging up the fuel pump? If you're unsure, turn the key to run without starting the car and see if you can actually hear the fuel pump cutting off.
Old 12-23-04, 02:25 PM
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Thanks Jeff,

Ran the wires to the ignition switch with no luck. I am going to pull the fuel pump off next to see if that has anything in the actuator and try it again.

Old 12-23-04, 04:00 PM
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Before you go taking anything apart, simply check for power and ground at the pump at the time it is failing. It's pretty simple, if you have power and ground and the pump won't run, it's bad. Be sure to check the plug connecters at the pump also.

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