I would really appreciate if someone could please provide some suggestions as to why the fuel pump fuse located on the firewall of my 88 IROC keeps popping. Sometimes it will happen when I attempt to start it up, other times it occurs while driving - therefore killing the car. I have replaced the fuel pump, the fuel pump relay, as well as even purchased a Racetronix kit to hopefully give some longevity to my fuel pump (Walbro 255lph). I know it could be a short somewhere or anywhere for that matter, but if anyone has ever had this problem before or has an idea what may be the cause, please fill me in. TIA!

 

Disconnect the harness from the relay and from the sender by the tank. . Hook an ohm meter (analog is best for this) to the tank end and ground. Now, shake the wiring under the car and watch the needle on the meter, if it twitches you have a short, next hook the meter to the relay end and ground and shake the wiring in the engine bay and look for the twitch. Do that to all the wires from the relay to pump.

The next step is harder, Hook the meter to the tank side of the wiring and to ground and shake that wiring as best as you can, again look for the twitching needle.

 

I had a problem with this and found that the wires at the fuel pump relay were bare at the connector and occasionally made contact with each other and were shorting out causing the fuse to blow. Total PITA until I cut the wires and spliced in new ones.

The Trickster!!!!!!!!!!!

 

Even easier than splicing new wires onto the relay end is just shortening the ones you have and reconnecting them to the pins inside the connector. It's difficult to remove the terminals in the connector, but when you pop the top of the connector loose at each terminal, the terminal just pops out. Then you use something pointy and spread the terminal connections and put the "new" end of the respective wire in and crimp the wire in place. There will be five plastic arrow-shaped holding devices inside the plastic of the termnal which have to be pulled up (if you pull it out, you broke it!) by a thin pointy device for each terminal to release. It might help to label the connector on a piece of paper as to how the wiring reconnects to the terminal block in the relay and to clean the wires while you are in there.

 

I had to splice new wires in because mine were bare at the pins and shortening them would have made the harness too short!!!!! That is why I removed each terminal pin one at a time and repaired the wire and re-inserted it in the connector and applied di-electric grease.

The Trickster!!!!!!

 

Hey, I had to cut about 1/2-3/4" off of each wire that the terminals, and I can still use the firewall mount, but I guess that each case is different depending on the age of the wiring.

And I hate that dielectric grease... I took it ALL out and did not even think about putting it back... It's just a PITA to me, even if it does repel moisture...

 

Incidently I had figured that my fuel pump relay wiring may have been the culprit and sliced new wires and a connector a couple months ago. I guess I'll have to try and multimeter wiring jiggle test