[2004GT]

I have a 2004 Mustang GT. I washed my car one day and when I tried to put it back in the garage it barely started and was struggling to keep running. Prior to this I have had no issue at all as to the running of the car. Now it will crank but not start. I think its the fuel pump as I do not hear the priming sound. I checked the fuel pump fuse in the engine compartment and its fine. I checked the inertia switch in the trunk and it feels depressed. I unplugged it and re-plugged it in but no change. I have heard about a fuel pump relay but have no idea as to where it is. Some say under the seat but I don't see it. Has someone else had this problem and can help me out?? Am I even running down the right road? Thanks

[MUSSL]

You definitely need to locate that fuel pump relay and be sure it is working. If it is working, check that you are getting spark to the plugs. You could have an ignition problem.

[AJCaron12]

Originally Posted by 2004GT

I have a 2004 Mustang GT. I washed my car one day and when I tried to put it back in the garage it barely started and was struggling to keep running. Prior to this I have had no issue at all as to the running of the car. Now it will crank but not start. I think its the fuel pump as I do not hear the priming sound. I checked the fuel pump fuse in the engine compartment and its fine. I checked the inertia switch in the trunk and it feels depressed. I unplugged it and re-plugged it in but no change. I have heard about a fuel pump relay but have no idea as to where it is. Some say under the seat but I don't see it. Has someone else had this problem and can help me out?? Am I even running down the right road? Thanks

Did you hose down the engine compartment when you cleaned your car?

[Silver Mustang]

Your fuel pump relay is located under your passenger side fender, between the fender and the fender well as shown in the diagram below. Your fuel pump relay is built into your CCRM, Constant Control Relay Module. It's 3 relays in one unit. One relay for your fuel pump, one for your fan circuit and the other for your AC circuit. If you don't hear your fuel pump priming, check for voltage at your fuel pump wire connector. It is located at the rear of your fuel tank above the rear bumper. Disconnect the wire connector and use a voltage tester to test the side that is running to your inertia switch, not the side that runs into the gas tank. You need a helper for this test. Your helper has to turn the ignition switch on to the on position, at the same time you need to have your test probes at the terminals inside the wire connector. Their should only be two wires there, one will be a ground wire and the other a hot wire. You will only see voltage for two or three seconds with the key on, and that's it. So, you have to really pay attention to what you are doing. Try this two or three times to make sure. Your helper will have to turn off the ignition switch and turn it back on to the on position each time. If you don't see voltage at all, then you have to back track to see where the problem is. If you do pick up voltage for that 2 to 3 second period, then your problem is your fuel pump. It must be replaced. Let us know what you find, so we can help your further. Hope this helps. Good luck, Tommy.

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[2004GT]

Update..I listened at the gas cap (removed) while turning on ignition switch. I can hear a faint whine for about 2 seconds. Is this the fuel pump?? Is it really that faint? If it is working I guess I need to pull the fuel filter and see if its clogged.

I will also try the voltage test posted and let you know. Thanks guys for all your help.

[2004GT]

No, I didn't hose the engine compartment. I had the hood closed and was using a normal garden hose attached to a hose bib on my house. I sure hope that didn't do it!!

[Silver Mustang]

Originally Posted by 2004GT

Update..I listened at the gas cap (removed) while turning on ignition switch. I can hear a faint whine for about 2 seconds. Is this the fuel pump?? Is it really that faint? If it is working I guess I need to pull the fuel filter and see if its clogged.

I will also try the voltage test posted and let you know. Thanks guys for all your help.

What this tells us is your fuel pump is working. So, eveything electrical between your fuel pump relay and fuel pump may be ok. If you are only picking up a faint whine, it could mean that your fuel pump is going bad. The only way you will know for sure how much fuel pressure your fuel pump is pushing, is to install a fuel pressure gauge on your fuel rail. To get your engine to start and idle, you need between 35 psi and 40 psi of fuel pressure. Only a fuel pressure gauge will give you that info. Ford uses the fuel pressure gauge shown in the diagram below. I'm sure your local automotive parts store will have one that will work for your engine. Good luck, Tommy.

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[sundownmaalpine]

may be a cloged egr valve. take a screw driver or something hard and tap on it. the vlave may be stuck shut, for which it is not letting air into the intake so it cant idle or start. (i had the same problem.) sorta.

[2004GT]

It took me awhile to get back to work on the Mustang but I finally have. I replaced the fuel filter and it was full of fuel. I tried to start the car but same thing..nothing. I pulled off the end that goes to the engine to check for blockage and found nothing. But there was also no fuel. It was dry as a whistle. Was I supposed to do something else after I replaced the filter?? I turned the key off/on a number of times to prime it. Is there a step I skipped?

I also tried to find the electrical connector from the fuel pump to try Silver Mustangs voltage check. But I can't find it. Is it necessary to remove something to access it?

Thanks guys

[mell0]

also a simple thing to check would be your inertia switch. it's located on the drivers side rear bumper inside the trunk. make sure it is plugged in and make sure the red button on top of it is pressed down. see the picture attached.

[2004GT]

Yes I checked it and it is depressed. I also unplugged the wires and checked to make sure there was a circuit on the switch contacts and there was. So the switch is functional.

I'm starting to get the nervous feeling I have to remove the gas tank. Never done that!!

[YFZ450er]

Hey, this sounds like the problem I had when I broke the anti theft system wiring that goes the ignition. I dont think it has anything to do with the way you washed your car. Basically its a wire that connects to a copper ring which acts like a sensor and reads the chip thats in your key IT IS PART OF THE PATS SYSTEM. I wish I could remeber the exact name. Unfortunately it is a dealer only part.