1991 GT Convertible won't start

[TXstang347]

My '91 won't start. She cranks and turns over but she won't start. She was running fine and then I turned the car off and she wouldn't start. I got her to start back up only once and got her home safely. It sounds like the fuel pump is turning on and working, but that would be my first guess. Is there any way of testing for fuel pump failure without pulling and replacing it with a new one and just crossing my fingers that it starts up.

The car is an all stock 5.0 auto. The fuel gauge is working properly and the tank is half full. I never had any problems with the car or warnings that something was wrong.

Thanks in advance gear heads!
Pony Joe

[troysmith]

there is a nozzle located on the fuel rail by the intake that looks like a valve stem only steel.. the purpose is to run fuel injection cleaner thru the system but you can turn on your key and take a small tool and push the core in and you should have fuel.....just in case you get no fuel ...your fuel pump relay is located below the drivers seat.... sometimes they get unplugged and overlooked but it has to be plugged in.. but if you said you can hear the fuel pump the it has to be. other than that check to see if your getting fire to the engine. if you are getting fire and fuel then it maybe a timimg issue..ive even tried a small shot of starting fluid into the throttle body making sure it goes into the intake and this will narrow it down quickly if it fires then you have a fuel delivery problem if it doesent you likely have a firing problem. if thats the case i say check the modual in the distribitor.. good luck

[TXstang347]

I finally had some time to look at the Stang. Still won't start. Here is where I am:

1) Fuel system is pumping fuel it's just not getting to the engine. I disconnected the fuel line between the engine and fuel filter (to determine if fuel pump was working and if filter was clogged). Fuel spilled everywhere. So it's not the pump, filter, or sending unit.

2) I have spark. I tested the spark plug wires. They all had 12 volts (tested at the point where they connect to spark plug. Is there anything else I should be testing here?

3) Fuel pump relay is connected. Am I right in assuming that it's the little black box under the driver's seat?

4) Timing is on point and not the issue.

5) I shot starter fluid in the throttle body and it started for a few seconds then died. Sounded strong too.

Any ideas on what the problem might be? Computer maybe? Is there anything between the fuel filter and engine that might have a clog or might have failed?

Thanks again,
Joe

[TXstang347]

STILL WON'T START! HELP!!!

This is what I've done up to this point. I started with the most basic things I could think of. The most odd sign is that I can hear the fuel pump priming, but it doesn't shut off after 2 or 3 seconds as it usually does. As long as I have the key in the on engine off position the pump keeps priming (making that whine/hum sound). I thought it was a failed fuel pump relay so I replaced it but the one I got from Advanced Auto parts was crap and even when I took the key out the fuel pump stayed on. So I put the original back on and it stopped with the key out. Everything I've checked so far:

1. Siphoned out old gas. Put in new/clean 93 octane.
2. Test fuel pressure at the shroeder valve. I got 40-42psi with key on position and 38-40 while engine cranking.
3. Replaced fuel filter.
4. Replaced fuel pressure regulator (that was one hard piece to get to, I had to remove the throttle body, maf ducting, loosen the fuel rails, disconnect the heater core hoses just to make room for the hex tools and my hands to loosen the FPR!)
5. Replace battery (wasn't holding charge).
6. Cleaned carbon deposits from entire throttle body area.
7. Tested injector wiring harness for voltage (good).

The spark plugs are completely dry and the engine just keeps turning over. It does start and run with starter fluid until it burns up, then dies. So apparnetly I have fuel up to the pressure tester valve but it's not coming out of the fuel injectors. Is there a fuel injector relay or fuse? I've checked all the fuses and they are all fine. Could this be a bad sensor confusing the computer? I was told there was a fuel injector relay above the EEC IV, but I didn't see one and no parts stores carry a replacement. Has anyone ever heard of the fuel pump failing and still working (priming)? Could this be a vaccum issue? If so how do I test/check for vaccum pressure?

I've ordered a Code reader so I'm waiting on that. Next step will be replacing the fuel pump (I'm going to be pissed if I spend $100 and drop the tank and the car still won't start). After that I'll be at a loss.

HELP!!!!

[skyhazzard]

HELP, I have the exact same problem, I have already replaced the fuel pump, filter, and fuel relay...
do you have to purge the fuel lines after a pump replacement?
The pump was not priming so I replaced it, then found out it was the relay. Now the pump primes but no start, so I replaced filter, still no start. Plenty of fire from the plugs and timing is right on the mark... Guess I'll be towing it to the shop next week.

[skyhazzard]

Helps if you put the return and supply lines on the right side of the sending unit, lol I love to learn the hard way. Anyway, now the car is starving out at 25 -3500 RPM... Any ideas. Didn't have this problem before...
Thanks

[OldSVTGuy]

It sounds like you've addressed several possible causes. I know it sounds lame but it has happened to me on several occasions with other cars. Try replacing the cap and rotor with Ford branded items. On these occasions, the car was running fine then no start the next time. Do not, repeat, do not use generics for this replacement. It's a possibility. Another possibility is bad spark plug wires/plugs?? There is also the ignition module on the side of the distributor that is a possibility but you get no spark when this goes bad usually. Are you throwing any codes?? Maybe a bad IAC or throttle position sensor?? Have you tried cleaning the MAF with spray cleaner (DO NOT TOUCH IT WITH ANYTHING).

Some suggestions, hope you get it figured out.

[skyhazzard]

Ok, Fixed, when I put hte tank back up, the supply line and return line crimped on each other. Go figure, I thinl I'll stick to my daytime Job

[OldSVTGuy]

Well, at least you figured it out. Good for you. And, it's always a good thing to check out where you last did some work to ensure you got everything back OK.

[HiFlow5 0]

Sounds like the TFI module located on the distributor. It's prone to cause problems intermittently, espically when heat is a factor. Shouldn't cost too much at your local parts store.

[86crazyhorse]

I had the same problem with a buddies car it was the fuseable linke off the starter solinoid on the firewall. If you hot wire the pump it will work. That's what we did he was to lazy to fix it the correct way. Hope this helps. Also the b est way to check your fuesable link is with a jumper wire with alligator clips on each side of the link.