Fuel pump fuse blows

[Oldbarefooter]

I have a 2000 Sunsetter LXI with a Monsoon 310 (Chev 5.7). The fuel pump would not spin up when I turned on the key. After much swearing, I found the wiring harness fuse block under the cover for the ECM. It looks like a wide plug, but removing the cover uncovered three 15amp fuses. The middle fuse blows immediately when the ignition key is turned on. The motor cranks and all the 12V accessories work. However, no fuel pump and no power from the coil.

The fuse blows with the power plug connected or not connected to the pump. I have also tried a different fuel pump. Also getting power (12.5V) on both sides of the circuit breaker.

Thanks,

Oldbarefooter

[23LSVOwner]

Could be as simple as corrosion in the wiring.

I'd throw a millimeter on the wiring and see is you are getting a high ohm reading. Also, take a good look at the fuse socket to see if there is any corrosion in there. Make sure the power is off when testing the ohms as a powered circuit will skew the readings or worst case, damage one of the cheaper meters.

 

Also check the voltage at the fuse, with the pump connected and with the pump disconnected (while running). Low voltage can cause high amperage because the load does not change. As voltage goes down, amperage goes up to power the load.

[Oldbarefooter]

23LSVOwner,

Thanks for your  reply and suggestions.