[Joestang]

This site has been very helpful. Thanks.
We got this 2001 mustang 3.8 with 75k mi. a month ago and we are trying to get it in shape. We did a lot of basic things, plugs wires, fuel filter, air filter, seafoam, cleaned MAF and intake. But it still is a bit of a dog and seems to hesitate on acceleration. It is also hard to start when sitting for a couple days. I put a fuel pressure tester on the fuel rail after sitting over night and it had near zero pressure. I cycled the key on and off a few times to get the fuel pump to pressurize the system. On the first cycle the pressure still did not register. After four on off cycles the pressure built up to 20 psi and it started on the 5th cycle. The pressure went to 32 psi while idling and would vary from 22 to 42 while reving the engine. After we shut the car off it maintained 32 psi for the next 2 hours. Then we removed the pressure tester.
Any thoughts on what the most likely cause is for this problem? Do I need a new fuel pump or any other ideas or tests I need to run?

My son took the car off to school this week and will hope to fix it next weekend when he returns. Next week I will alsonbe taking the gas tank down to replace the fuel fill tube and gasket.
Thanks,
Joe

[clidefr0g]

how long did you leave the key in the on position each time? and were you trying to start it each time? or just turning the key to on?

i am thinking it might be a coil pack, depending on your answers to those questions.

[Smoothgrandmama]

Shot in the dark but it could be the FPDM going out? it's still a drop the tank and see thing though...

[Joestang]

When I had the pressure tester on the car I just turned the key to the on position for about 15 seconds each time but did not try to start the car. Each time I turned the key to the on position the pump would run for about two seconds. After we got the pressure up to 20 psi we tried to start the car. I think it is getting good spark. It just can't get fuel without cycling the pump.

what is the FPDM and does it come with the fuel pump module? or is it separate?

[clidefr0g]

its the fuel pressure driver module, you could try resetting the inertia switch, or checking for a short circuit. The inertia switch is in the trunk.

[rafter40]

i just replaced my fuel pump on sunday. i had virtually no fuel pressure at the shraeder (?) valve and i couldnt hear the fuel pump turn on. This was after a few days when the symproms progressively got worse to the point where the car wouldnt start even after many tries. here is a link to my thread i think it will help you diagnose if you decide to read over it
(i ask alot of questions) Car wont start

[Joestang]

Thanks for the replies.
How do I diagnose if it is the pump or the FDPM?
Is the FPDM located in the tank? What does it look like?

Most of the time the car starts and runs fine. It does lack power in my opinion. After sitting for a couple days you need to turn on a couple times to get enough fuel pressure to start.

I need to drop the tank in a week or two to replace the fuel tank fill tube. While it is down I may just replace the fuel pump anyway.

[Joestang]

FYI
We replaced the fuel pump and the fuel fill tube. Easy project. Took a couple hours but went as planned. The pump fixed the hard start situation. But the car still runs a little rough. My son doesn't notice it but it just doesn't seem right to me.
I did find another problem. I found a IMRC linkage disconnected on the passenger side. I reconnected it, but I do not know if it made any difference. My son is gone with the car for at least a week. He said he did not notice any change. I would think it would have to make a difference if one side of the engine isn't getting the proper amount of air.

[wraitherx]

the FPDM is mounted inside the trunk. pull away the drivers side trunk covering and then you will see a little black box with a plug leading to it. It will be mounted onto the metal brackets back there. Its hard to miss it.

[Joestang]

Thanks, but the car runs much better now with a new fuel pump and the IMRC linkage reconnected. It finally has some torque and just seems to pull a lot better. I may not have been clear before but the IMRC linkage that was disconnected was located on the back of the intake manifold passenger side. It is very hard to get to or even see.
Now I feel like the car is running right and is ready for intake and exhaust upgrades.