I am having an issue where my fuel pump fuse keeps popping. The fuel pump has been rewired with an aftermarket 40amp relay 30 to battery, 87 to pump with 85 and 86 power and ground. I ran a 30 amp fuse between the battery terminal and pin 30. The fuse is a 30 amp inline fuse that pops when fuel pump plug is plugged into sending unit. Replaced the hanger and fuelpump. My main relay is an aftermarket 40 amp feeding 12v switched power to an aftermarket ecu. The car had the issue with no fuel and spark before the ecu/wiring was done. Any ideas on where to look?

 

I suspect it is wired incorrectly and shorting out popping the fuse.

I would confirm all the connections including if they are in the right spots etc. The hard part is, since you wired it, it will look correct as it fits the information you have in your mind. So an error will be hard for you to see. Another set of eyes might see an error before you.

 

Correct me if i am wrong but, on a 4 pin relay 85 and 86 can be interchanged from my understanding. This weekend I tested all the fuses under the dash and under the hood/ relays with a test light and continuity checked out on everything, no popped fuses besides the fuel pump one.

 

Measure the resistance of the fuel pump? It should be 1-3 ohms. If it's less, the pump is defective. If it is okay, then the wiring has a short to ground.

 

Today I managed to pull the pump out of the tank and test that it cuts on and primes. Weirdly outside of the tank it cuts on and primes like it is suppose to. Once I close the tank up with or without the 2 fuel lines connected to the sending unit it pops the inline fuse.

 

Thought maybe the ignition switch was causing the short, replaced it and nothing. Tonight I will disconnect the alternator and see if it keeps popping fuses.

 

The fuel level float plug had melted wires. Lucky the car didnt catch on fire. Anybody know of a simple way to unhook it, plug location under the dash etc?