Just shuts off
 

Please help, I am having some trouble. My car will be running great, and then just stop. It might start or might not. When it does this I can not get my fuel pump to work(like when you turn on and off the key) It does not happen just when you are driving it. It just sat all night, when I went to start it this morning no fuel pump and it would not start. I also loose spark too when this happens. Please help.

What year and model is it?

It is a 1993 GT 5.0 302 5-speed.

I'm 98% sure it's your fuel pump. I had the same problem. It will run fine and then quit, after it cools down it does the same thing.
It also might be your modulator in your distributor, the other 2%.


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Mike Wigton
89 LX 351W
64 1/2 Convertible

I just replaced the fuel pump, module on dist., fuel pump relay, PCM relay, Now I am leaning on replacing the ignition switch and the plug.

here's another last resort idea, the inertia switch underneath the passanger's side of the dash. If it's faulty it would cut out both spark and fuel and it would be fairly random. Hope this helps, keep us posted!

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'84 Mustang 5.0 LX
My car

What exactly what is the inertia switch.

THe inertia switch is a means to cut off fuel and spark in event of an accident. So you dont blow up, or do damage to your engine.

I havent had a fuel pump give me problems like that, the relay yes, but not the pump its self. I was going to say check you ignition module but you already replaced it.



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64 1/2 "D" code Red Mustang Coupe. 289, C4, Mallory duel point. Ported & Polished 65 heads shaved .01 with 351 valves, 11:1 comp, 1.7:1 rockers, blue wolverine lumpy cam, modified 4100 Hipo 4 barrel. GT Apperance pkg. And to many others to list

2000 Perf Red Mustang GT. 5spd. BBK Underdrive pulleys, Flotech off-road H pipe. Hurst T-Handle, 40 series Flowmasters
64 1/2 red 6cyl coupe. Auto. project car. http://cwm.ragesofsanity.com/contrib...uble0smile.gif

I had a similar problem...mine was the Stater inside the Distributor....it could be the inertia switch/fuel pump relay too. It is located under the drivers seat.

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Dustin
Saleenized 89 GT,428 rwhp,TFS Street Heat Intake,TFS TW Heads,TFS #2 cam,BD-11A 9 psi,FRPP 1.6 rr's,BBK 70mm TB,Pro-M 75mm Bullet,MSD 6BTM, FMS 9mm wires,BBK longtubes,BBK Short H-pipe,American Thunder cat back,3.55's

12.3@119

Since both your spark and fuel are affected you should be looking at parts that effect both systems.

That can throw the fuel pump relay, ignition module, stator, and tons of other parts out the window.

What you are left with is the ignition switch itself (mine went bad and the result was EXACTLY what you describe). Also the PCM itself, since it controls the fuel pump relay and the ignition. I'm not sure if the inertia switch controls ignition too, my experiance with that switch is, it's all or nothing. There is no intermittance involved. Since it merely completes a circuit, there is no reason for it to be intermittent.

I would put money on the ignition switch itself.

Good luck.

By the way, the interia switch is located in the hatch area. On the very back panel you'll see a black rubber plug on the drivers side. That covers the inertia switch. If you pop the plug, you should be able to feel the switch on the wall supporting the taillights. Removing the back plastic panel will provide full access to the switch. Once you have access, if you suspect the switch is bad, disconnect it, and stick a jumper wire into the pigtail jumping the wires going in. If the car then works, you know you've found the problem.

I have similar problems in my car. When it's really hot oustide (98* or more) my car just dies and doesn't restart. I lose spark, but according to the fuel pressure regulator I have plenty of fuel. We ended up diagnosing it and found out I had a faulty computer. The car works great now. I also own a 5spd '93 GT.

When it just stops, do all the lights on the dash go off? Do you have a huge key chain with every key you ever owned since your first bike lock? If so, it's likely the ignition switch.

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351W 89 Mustang GT Convertible

I had a car that did that. It turned out that I just needed to make sure the battery connections where tighter. I thought it was something more complexed but it was not. Sounds simple but it worked for me.

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Red 90 5.0, 17in Cobra Wheels, Saleen Wing, Cobra Ground Effects, K&N intake, Dual Flowmaster, Hurst Shifter

Guys, I think I found it. Someone cut a wire sometime ago, and it was not making a good connection. It would just take a little movement to make it work and to make it stop working. Thanks for all the help, and if it is not it I'll be back on asking again.