bluestang96

My wife is having problems with her 91 5.0 convertible. When you turn the key you can hear the fuel pump sending the fuel but the system does not seem to pressurize as it just keeps pumping. I took the cap off the schrader valve and it is pumping fuel very well.

I did get it to pressurize the other day and it started and I let it run for about 5 or 10 minutes and then shut it off. It would not restart and the system was not pressurizing again. What can be causing this problem? It is driving me crazy and my wife wants her convertible back as she doesnt like driving the 2001 coupe.

PRO50SC

What are you basing the fuel pressure on. Are you using a gauge? What is the pressure? Don't assume just b/c there is fuel coming out of the rail it has enough pressure.

nitrous_bob

yeah for$35 you can have a rail guage in there and check out whats it doing when it's not doing it right

bluestang96

Okay. I went out and bought a fuel pressure gauge. With key on I am getting 40 pounds of pressure. It did start this morning and it gave a steady 32 pounds of pressure at idle and under load.

I drove it 10 miles to Lowes to pick up some stuff for my garage and it died just as I was pulling into the parking lot. It choked once going down the highway. I sat for about 45 minutes and then the Stang fired back to life and I drove it home and put it in the driveway. I shut it off and attempted to restart it but once again it will not start. I did notice when I turned the key on there is a hissing sound under the hood.

TwotoneVert

Your problem may not be fuel relatated. If you had a leak, surely you would see or smell it.

nacanitihs

where did you buy a damn gauge?!?! i look freaking everywhere!

mjr46

your problem may be ignition related to rule out fuel pressure drive down the road with the gauge taped to the windshield if you slowly lose pressure and it stalls out may be fuel related like plugged fuel filter or partially plugged fuel strainer on the end of the pump or a weak pump. if it's not fuel check ignition system a classic symptom of a stall and it'll restart after about a 45 min cool down maybe less or more could be a tfi module crapping out.....you can test them with a ohmmeter

bluestang96

You can buy your fuel pressure gauge at Advance auto parts for $36. It doesnt have a long enough line to tape it to the windshield but I will start it when it will start and let it run and see what happens. Someone hear said it may be the TFI module so I am going in that direction. Would that cause it to not pressurize the system when you turn the key on though?

marx91

that sounds more like the TFI is going bad, than it does a fuel problem, the TFI wouldnt effect
thefuel pressure

dillon1340

i think that sounds like a tfi problem. nothing you said about the problem is specific to a fuel issue.