Fuel Pump went out 98 GT?

Timin · May 29, 2011

I've researched some of the other posts on this subject and I believe the fuel pump went out in the car. A little history of the car, it has not been driven in over a year and has been sitting in outdoor covered parking for 9 months, a garage for the last 3 months. When I crank the car it does turn over without problems, but will never completely turn on. We poured a little gas into the vaccum line running into the intake, the car cranked for a brief 1/2 second or so.

There was roughly 1.5 gallons of gas in the tank, I did not use any stabilizer. When I turn the key in the On position I do not hear the pump turning on like I had in the past, but I do hear 1 click shortly followed by another click in the engine bay.

The fuse is good, so I went to the trunk and the switch is pressed in like normal. I am getting 6.9v from each side of the switch when the key is in the On position. So it seems the switch is getting power, so the relay and switch itself are good. Is there anything else left to check before determining that the fuel pump needs to be replaced?

-Karl

nyuk98gt · May 29, 2011

Timin,

Here are a few things to check out.

Try your second (spare) key. Maybe PATS is interfering with the start-up.

The filter may be clogged.

How's the battery? New or recharged?

Is there decent pressure at the fuel rail (Schrader valve)?

The poor car needs some fresh fuel, lol. Since you hear just a click or two, it could be that the pump has "gummed up" and won't [can't] turn (or, maybe it can't push against the plugged filter). You can try running 12V to it directly to see if it will run. Also, remember that the pump needs some liquid on top of it (referred to as 'suction head'), especially if the sock filter is a bit dirty.

HTH,

Chris

fast97gt · May 29, 2011

hope not the ccrm. but 6.9v seems a lot low. it should be 12+volts in and out.

Timin · May 30, 2011

I believe everything is okay with the PATS system. When I turn the key to the On position it comes on for 2 to 3 seconds and then goes away.

The first thing that came to my mind was the little fuel that was in the car would of gummed up over the past year. I have a new fuel filter as well, so I will replace that this week once I get back in town. I know I will find out more once I replace the fuel filter, but should I worry/do anything about any possible "gummed up" fuel lines? I was going to stop by and get the tool to check the pressure at the fuel rail, i'll test it this week when I replace the fuel filter.

It is a new battery that has been on a battery charger, so we appear to be good in that department.

Since trying to crank the car back up (January and earlier this week) I have put 4 fresh gallons of gas in the car, so currently it is sitting right over a quarter tank.

Would the fresh gas that has been poured in the tank be enough to get liquid on top of the fuel pump, or is there another way to do this? Also, when running this wire I just run it straight from the battery to the Switch in the trunk, then try to hear the pump power on/crank the car?

Appreciate the help

-Karl

trinity_gt · May 30, 2011

I would put a fuse in that power wire near the battery...

6T9_CHARGER_RT · May 30, 2011

More than likely its the pump...same thing happened to my 99 GT over the winter from sitting...see my thread here....

http://www.stangnet.com/mustang-forums/835287-fpcm-go-bad-sitting.html

Nimit · May 31, 2011

Timin - I believe that your problem is that your mustang gt SUCKS! J/K Karlitosway! Let me know when you're ready to takle the Stang again.

98GTragtop · May 31, 2011

It sounds like the fuel pump to me. I am starting to have the same problem and your situation sounds familiar. Luckily mine is only failing to start every once in a while. Make sure you check your inertia switch before replacing the fuel pump to make sure it didnt trigger. If you do decide to swap out the pump send me a PM with what kind you are going with. I would like to know how you handle it.

GDawg · Jun 1, 2011

98GTragtop said:
It sounds like the fuel pump to me. I am starting to have the same problem and your situation sounds familiar. Luckily mine is only failing to start every once in a while. Make sure you check your inertia switch before replacing the fuel pump to make sure it didnt trigger. If you do decide to swap out the pump send me a PM with what kind you are going with. I would like to know how you handle it.

Check the inertia switch...

sneaky98gt · Jun 1, 2011

If you do replace the fuel pump, I'd recommend upgrading to the SVT Focus pump. It drops directly in place of the stock pump with no problems at all, and when I bought mine, it was cheaper than a stock GT pump. If you do decide to do that, post up and I'll dig up the number from Steve @ Tousley Ford. I went to 5 dealerships locally, and none of them had a clue what I was trying to do by swapping the Focus pump in, and none of them knew how to tell if it was an SVT pump. I called Steve and he immediately knew what I was talking about and hooked me up in prompt fashion.

Timin · Jun 1, 2011

I do not have much experience working on the car, so I may be asking questions that you would normally not hear. I wanted to make sure I troubleshoot this correctly so we can diagnose the problem. How exactly am I supposed to try and manually power on the fuel pump? Based on reading many different posts, my presumption on how to do this would be to unplug the connector that plugs into the Inertia Switch, and then run a wire from the Positive battery terminal to the RD/BK pin, and a wire from the Negative to the BN/PK pin?

As long as I can verify power leaving the FPDM, if the Fuel Pump does not power up after this test then it would appear there is nothing else left but a bad pump?

-Karl

nyuk98gt · Jun 2, 2011

Timin,

You've got it but the ground wire is not necessary. My Haynes manual shows a brown/pink wire from the inertia switch to the pump and the pump is grounded. You should just need (fused) power supply to the brown/pink connection to the pump. If it whirs then it is doing something but you may want to put a gauge on the fuel rail to see what pressure is being developed.

The '98 does not have a FPDM, just the constant current relay module (CCRM) in the passenger fenderwell (behind the plastic liner).

HTH,

Chris

Timin · Jun 7, 2011

Latest update: Previous testing for power at the Inertia switch has resulted in 6.9v on each end. I've got my hands on a different meter I am going to be testing the voltage today after work to try and confirm the voltage. The battery is a spare battery I had charging on my battery charger, not sure if a non-fully charged battery could be a reason why we are seeing less than 12v at the Inertia Switch.

Will also run a jumper wire from the positive end of the battery to the switch to see if I can manually power the pump

-Karl

Timin · Jun 7, 2011

Was able to verify 12V at the Inertia Switch in the trunk. I believe since there is no FPDM in the 98's then this verifies that power is going from the switch to the Pump. Aside from a busted wire or messed up ground, all signs point to the Fuel Pump I believe?

I am going to go with the SVT Pump, part number 3S4Z9H307BC/PFS-204

Timin · Jun 28, 2011

Late Follow up: Replaced the pump and got everything put back together, and the car is back up and running.

Thanks everyone for the help!

nyuk98gt · Jun 30, 2011

Timin,

Thanks for posting the update(s). Very helpful to future StangNetters who have the same or similar problem.

Chris

chunger · Jul 26, 2011

Just ran across this thread since I have the exact same issue with my 98GT, which has sat for 9 months. Thanks for posting your updates and fixes, hopefully this will save me some time in tracking down my issue!

1987stangman · Jul 27, 2011

chunger said:
Just ran across this thread since I have the exact same issue with my 98GT, which has sat for 9 months. Thanks for posting your updates and fixes, hopefully this will save me some time in tracking down my issue!

I would follow this post but I would go to harbor freight and buy a cheap 20$ fuel pressure tester.

chunger · Jul 27, 2011

That's an excellent idea. Right now I've got 0 psi (easy enough to test at the Schrader valve). But, assuming the same trick works on my car, knowing the fuel psi is still good.

I'll pick one up later today.

Fuel Pump went out 98 GT?

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