Engine shuts off while driving

[grandpaslincoln]

I figured I might as well put this here for technical reasons.


For some reason, while driving GL's engine will just shut off, like I turned the key off. I can put it in neutral while coasting and I can start it right back up. Then it will run alright for a few minutes, and the engine will shut off again. I can repeat this procedure many times. I've checked and replaced the coil, I took out the Crane Cams electronic points replacement kit with regular old points, and it still does it. I've wiggled every wire having to do with the ignition system, including the plug to the ignition switch, I've wiggled the ignition switch around by turning the barrel around a little, and it doesn't do anything. What the hell is going on here? Could it be the starter solenoid? Since just about everything electrical routes through it, could the fault be there? I need to figure this out ASAP, because as it is, GL is the only car we have, me and my dad share it to go to the store and do laundry, and now I have no way to get to work, so I'm probably going to get fired I can't drive it like it is, I can't take the chance of it breaking down in the middle of town and not being able to get it moved out of the way. I'm at a complete loss here.

I know if I install the duraspark stuff that Scott is going to send me, it's going to have the same problems. Can anyone help me here?

[gadget73]

Try starting the car and running a jumper wire from where your ballast resistor or whatever is direct to battery +. or, if you're running a 12v coil, jump it straight to battery +. If that fixes the problem, you have an electrical fault in either the ignition switch or some wiring between the battery, the switch, and back to the coil. Don't you have an electric fuel pump too? Could it possibly be the fuel pump is losing power and its dying? I'm hesitant to say so but it never hurts to check.

[gadget73]

Another thought, don't you have a tachometer? Is it hooked up? I've seen bad tachs short out the ground side of the coil and it will do much the same thing as you're experiencing. Does the tach drop straight to zero when the engine dies or does it stay roughly where it should? Dropping to zero might indicate either a loss of ground to the distributor or a short to ground via the tach signal wire.

[grandpaslincoln]

The tach needle drops like a stone when the engine dies. I thought about the fuel pump, but it seems like it would stumble and sputter and then die, not just up and quit. I'll check it anyway though. Thanks mang!

[marquisman]

i had to put a new ignition switch in the LSC cuz it would run and sut off but i found this out cuz when i turned the key back i had no accessories and if i held the key in one position it would stay runinng so play with the key and see what happens(the switch its self came apart)

[grandpaslincoln]

Fixed!


The problem was in the underhood wiring harness, behind the alternator. The 12V power wire routes through there and connects to some kind of metal cannister, looks like a noise filter of some kind. The wire was crimped with a crimp tube, and a little bit of the wire was exposed, which was shorting against another bare wire under the tape. I rerouted the wiring and it runs good now. The only problem is the points need some adjusting or something, it runs a little rough sometimes. I may just put the electronic conversion kit back in.

Thanks for the suggestions guys, ultimately it led to finding the problem

[Paul_]

[Grand Marquis GT]

The job is still safe, I hope!

[grandpaslincoln]

Yep, still safe

I reinstalled the electronic conversion kit, GL runs like a top again!

[Archangel]

Glad to hear that, last thing you need now is a car that's acting up.

[gadget73]

Glad you got it tracked down. It took me over a month a a crapload of new parts to finally figure out the random backfire problem with my boat was a simple poor connection at a bullet connector between the distributor and ignition module. I changed out fuel filters, took the carb apart, changed wires, cap, rotor, swapped ignition modules, hot-wired the ignition, all to no avail. Every time I thought I fixed it, a few days later it would act up again. Finally I gave up and just started ignoring it when it was blowing fireballs out of the carb. I figured eventually it would either quit giving me shit, or it would actually break and I would be able to find the problem. Finally it just shut off while running and I fixed the damn thing out in the middle of the bay.