Help !!! Fuse for fuel pump keeps blowing !! Aww maaaann!

[Doctor Evil]

My 15 amp fuse for the fuel pump all of a sudden decided to blow, and when I put a fresh one in, it blows it immediately...


Sooooo, I am without any real voltage testing equipment, so what should I check for first ? Loose connections at the pump ?
Any electrical guru's ou there ?

Thanks in advance, Tom

 

[ChrisCairns]

You've got a hot wired pump .....

Start to trace the wire from the hot source, back through the car to the pump. Somewhere the wire is probably pinched and is shorting out.

 

[Mease Performance]

...

yeah what he said or possibly bad pump, if no go on the short, unplug the wiring to the pump (3 prong plug) , ground to battery and put 12V to the pump: purple is the SENDER WIRE DO NOT PUT POWER TO THE SENDER. listen for FP running, no go, pull tank, check wiring and replace pump.

<KM@MPE>

 

[Mease Performance]

...secondly:

I have seen BRAND NEW walbro 307's and 340m's go bad in a week!
no guarantee, so dont rely on the pump being good if you JUST replaced it.

<KM>

 

[DR BOOST]

is it the 15 amp fuse in the fuse panel or the fuse in the hotwire?

if its the hotwire fuse, then trace your hotwire. there must be a short in it

if its the fuse in the fuse panel, check the hotwire's relay for bad connections.



hth

surej

 

[Joe Tiano]

take a look behind the alt. and A/C compressor make sure the grey wire(fuel pump relay) is not melted on the driverside header!...joe

 

[darkfa8]

aside from checking at the pump and its wiring, also check the fuel pump relay on the passenger side inner fender well.

Make sure the coil isn't shot by putting a ohm-meter accross it, you should read resitance. You can also check for shorts to ground on the switched contacts as well for both the solenoid and the wiring.

 

[getchasum]

Originally posted by Joe Tiano
take a look behind the alt. and A/C compressor make sure the grey wire(fuel pump relay) is not melted on the driverside header!...joe

This is what was causing my to blow. Make sure to wire tie loose wires up out of the way, if this was the cause.

 

[salvageV6]

If it is the fuse in the fusebox labeled FP/INJ that is blowing unplug the connector for the fuel injection harness located under the coil pack and module.

Large square connector.

That will separate the two circuits on that particular fuse.

If it stops blowing after disconnection at that point it is a problem with the fuel injection harness.

First test would be to unplug the pump wires under the gas tank however.

 

[Nas-T-V6]

LOL! That loose wire touching the manifold happened to me last year too. I spent days trying to figure out what happened, then in the corner of my eye I noticed that wire melted against the manifold. Boy did I ever feel dumb. I feel your pain.

 

[Doctor Evil]

I checked the grey wire behind the alternator, replaced the fuel pump relay (because they were cheap 11.00) , looked very close for kinked or bare wires....found zero...nothing. Also checked the fuel rail wires for the injectors. Zippo


What I have noticed is that I can wait until the car is completely cool, and replace the 15 amp fuse in the fuse box, and it will start again , run for approx. 40 mins or so, then blows the fuse. My uneducated guess would be the pump slowly overheats....over amps...

I was wrong this whole time, my car is NOT hot wired....

Thank you for all the replies....any more suggestions, or do I have a bad pump ?

 

[ChrisCairns]

One last place to look before you tear out the tank.

If you look in the trunk on the left side in the fender area, you can see a herd of wires. The big clear copper one is the stock hot wire for the fuel pump. See if it's rubbing somewhere....it doesn't take much to rub off the varnish protectorant.

 

[darkfa8]

try changing the pump...

though i'd make sure none of the stock power wires for the pump are shorted to ground.

other thing you could try and disconnection the oil pressure switch connector at the front-lower passenger side of the block.. maybe that circuitry has a problem...

the stock fuel pump wire color in the trunk is tan, then after the connector in the trunk it changes to tan-white.

at the fuel pump relay, the pump power wire is Gray

 

[Kaz]

Thanks t all who contributed to this thread back in the day. The tips helped me figure out a problem today. I swapped out new injectors and when I went to fire her up the FP/INJ fuse kept blowing. Turns out I stupidly caught one of the injector leads under a fuel rail bolt. When I tightened it down it smooshed the wires and caused a short. I seem to have to learn the hard way some times.