1998 Mustang GT 4.6 fuel pump not working

amdy64 · 07-09-2009, 08:39 PM

80,000 miles. Car is not running.

I'm troubleshooting my fuel pump. It dosn't run when key is on. I hear relays clicking but no pump. On the wiring there is 4 wires going into the pump. Can i use a test light to check if there is power to the pump? If so what color wire do I check, and how long will it be powered up after the key is turned on?

I removed the pump today, the white wire inside the tank was almost cut through, I think it was connected though.

thanks, Amdy

K5Calamity · 07-10-2009, 08:31 PM

When you turn your key to RUN the ECM only runs the pump for 1-2 seconds initially. The pump will run continous only after the ECM senses that the engine is running via the ignition system. You can use a cheap test light to test for power back at the pump. My schematics (for a 94 GT) say test the BROWN wire with the PINK stripe. Thats the 12 volt source for the pump. There is no danger of damage to your computer. Keep in mine my info is for a 94 GT, not a 98, but it should be the same.

amdy64 · 07-14-2009, 09:07 AM

Installed new fuel pump and filter....Still not running. Must be a relay or fuse or something else.

K5Calamity · 07-14-2009, 09:12 AM

Quote:

Originally Posted by amdy64

Installed new fuel pump and filter....Still not running. Must be a relay or fuse or something else.

Have you already checked the inertia switch? If that's good, check to see if fuel pump relay is bad.

amdy64 · 07-14-2009, 01:04 PM

It's running now...It was the inertia cutoff switch...
Thanks for the replies.

bratt · 07-23-2009, 06:05 PM

where is the inertia switch?

I have a 98 mustang gt that will not start now.Ｉwas driving down the hill and it just shutoff. I found the negative battery terminal had corroded and lost contact so I replaced it. It still will not start though.

I ran a spark check and I have spark. I ran a fuel pump test and the fuel pump primes the fuel for a couple seconds when key is on.

K5Calamity · 07-23-2009, 06:09 PM

The inertia switch is in the trunk of the car, on the drivers side rear corner. You have to put your finger through a small hole of the carpeted trunk liner to push a button on the inertia switch to reset it. Thats its location on a 94 anyways. Should be same for 98

bratt · 07-23-2009, 06:12 PM

yea i pressed it but it did not help me

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