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Gary, Chevy Technician
Category: Chevy
Satisfied Customers: 16759
Experience:  15 years GM master tech
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Pickup: chev..2500/ 350 v8/ fuel pump wont run, engine wont start

Customer Question

1997 chev pickup 2500/ 350 v8/ fuel pump won't run, engine won't start. New pump installed, runs when wired directly. What runs the fuel pump, or prevents it from pressurizing the system?
Submitted: 6 years ago.
Category: Chevy
Expert:  Gary replied 6 years ago.
so when you turn the key on you have no power at the gray wire for @ 2 seconds?and when cranking no 12 volts at the gray wire?check the ECM B fuse to make sure it has 12 volts at both sides of the fuse with the fuse in place testing threw the little opening at the top of the fuse.if thats good then remove the fuel pump relay and with the key on the orange wire should have 12 volts,black/while should be a good ground,dark green/white should be 12 volts when cranking to energize the relay.if all 3 of those are good either the gray wire is bad from the relay to the tank or the relay is bad itselfgraphic
Customer: replied 6 years ago.
When the key is turned on, there is a click from a solenoid mounted on the inner fender near the fire wall and relay center. Does this power the relay center, and could it be a problem?

The engine started once after I had pushed on the coil wire. Has not started since. Could a bad coil wire prevent the computer from powering the fuel pump?
Expert:  Gary replied 6 years ago. can not cause this problem of the pump NOT running.get to the fuel pump relay and test what i said
Customer: replied 6 years ago.
ECM-B fuse has power. fuel pump relay only has power occasionally and the engine will start then when ignition switch is turned on. so is the problem in the key switch?
Expert:  Gary replied 6 years ago.
does it have power when cranking at the darkgreen/white wire when cranking?
Customer: replied 6 years ago.
No... dark green/white only has power occasionally - (1 in 200 tries) also ignition fuses only power up when the relay does. Truck has 210,000 miles, could ignition switch be bad and do you know any tricks I should know to replace it? By the way, the truck is stranded out in the country about 2 hours from my home computer. Sorry about the delay in communication. That solenoid that clicks when the key is turned on seems like a suspect as well.
Customer: replied 6 years ago.
The fuel pump relay is not getting power from the wire that activates it. ECM B fuse has power. Ignition fuses do not have power. Can it be the key switch is not making contact?