Question2004 Ford Mustang,
V8, 4.6 Liter
Manual transmission,
About 8500 miles
This car tends to sit in the garage most of the time with about a half hour run every few weeks. I use fuel stabilizer when it sits during this time.
I took it out for a ride the other day and it ran great. I went to various places over a period of a couple hours, dinner and a ride to drive it. Each time I shut it off and started it the car ran great. I stopped just before going home and shut it off. The last time I started it the engine ran very rough and without power. I had to have it towed because it eventually wouldn’t run.
In the garage I checked for errors with my OBDII tester and it said there were no errors. The engine spins over very well but doesn’t try to fire. I didn’t check for spark, but I did shoot some gas down the intake after taking off the intake pipe from the throttle body. When I tried to start it the engine fired right up but ran rough.
I checked the fuel safety switch to be sure it was not tripped. I restarted it and the engine ran great again. After a minute I shut it off, and then after a few minutes tried to start it again and all it would do is spin and not fire up.
I added gas (about four gallons) in case the fuel gauge was stuck. I also cycled the key on and off as recommended by the owners manual assuming it was out of gas. The engine just spins and doesn’t start.
The safety switch seems to have continuity when I checked it with a meter and the connector seems tight. I checked it in the tripped and reset positions.
The owner’s manual says this is a non return fuel system. My assumption is that the pump starts and stops to maintain pressure.
There is a device on the fuel rail with wiring connected to it on the driver side but doesn’t come off when the screws are removed. Is this a pressure monitor of some sort? Would this tell the fuel pump not to pump?
It appears to be a fuel problem since I can get it to start. My next step is to remove the fuel pump, but I would like to be sure this is the problem before I pull it.
What do you think?
Thanks.
Answeri would guess fuel also-run a fuel pressure test and that will tell you-i believe you should have at least34-35 lbs of pressure key on engine off and at least the same running-if the thing on the fuel rail has a vacuum hose to it it's a fuel pressure regulator-if it has electrical wires it is a fuel sensor and yes they do wierd things sometimes. take a hammer and bang on the bottom of the tank and see if it starts if so it more than likely the pump.
