1994 Isuzu Rodeo fuel pump fuse keeps blowing

HANDYMANLIFTER

MEMBER
1994 ISUZU RODEO
3.2L
V6
4WD
AUTOMATIC
170,000 MILES

Autozone customer service told me that if the fuel pump fuse keeps blowing, its because the fuel pump has a short. I replaced the fuel pump in the gas tank but it still won't start and it still keeps blowing the fuel pump fuse. Where do should I do? Please help thanks.

1 Reply

CARADIODOC

MECHANIC
33,737 POSTS

Fuel pump motors rarely short. What they should have told you is the fuel pump CIRCUIT has a short.

A simple trick to finding a short is to replace the blown fuse with a pair of spade terminals, then use small jumper wires to connect them to a 12 volt light bulb. A brake light bulb works well. When the circuit is live and the short is present, the bulb will be full brightness and hot so be sure it's not laying on the carpet or against a plastic door panel. Now you can unplug electrical connectors and move things around to see what makes the short go away. When it does, the bulb will get dim or go out.

Be aware, however, that the fuel pump must not run, other than for one or two seconds, when the engine isn't rotating, (cranking or running). That means the circuit will be dead even though the ignition switch is on. You'll need to bypass the fuel pump relay to keep the circuit powered up so you can troubleshoot it.