Mercury just shuts off anywhere and anytime

[Mainemantom]

My 1983 Mercury GM 302 with TBI runs well however it unexspectadly shuts off and will not start right up. The previous owner wired a jumper where you turn on the key go to the starter solenoid, unplug the red wire and hit the jumper wire to the solenoid. The car then starts right away. I have been at stop lights, making left turns or just trying to start it up when the car does this. Mechanics have looked at it and do not know. One just wanted to throw parts at it. Another mechanic said he does not know how to work on old cars like mine. Can anyone figure this one out ?? Thanks in advance.

[86VickyLX]

Does it matter if it's hot? Cold? Only at idle? With loads on the engine?

[sly]

engine ground wire maybe?

[Mainemantom]

It does not matter if it is hot or cold. It could be idling, moving. mostly does it on restarting. The last time it did it was while making a left turn crossing traffic. Good thing the speed limit was 25 mph.

[79lincolnlover]

Also check for a loose battery cable and vacuum leaks.

[fmansfield444]

Sometimes the ignition switch comes loose from the back of the switch on the column. I had this happen on every 80's ford me and my family have owned. When the switch comes loose the pin doesn't make contact to another part of the switch. And then shuts the car off.

I fix it by taking the steering column shroud off and using a zip tie to hold it together.

You can replace the switch but some require torx security bolts.

Usually when they break accessory doesn't work and the switch doesn't click when you go to start. Also the car will shut off when turning, hitting bumps etc. then eventually when it fully breaks it wont start at all.

And I'm talking about the box on the column under the shroud near the turn signal switch. Not the metal part you put the key in.

[86VickyLX]

Replace the switch before you set your car on fire mang!!! ^ All you need is a hammer and a chisel. Hammer the 'security bolts' on an angle so they will start to unthread. Once you get past a certain point, you can remove them by hand. Ford put locktite on the threads. When you put the new one in just run 1/4x20 bolts and lock washers to hold in the switch.

[rick99601]

Replace the switch before you set your car on fire mang!!! ^ All you need is a hammer and a chisel. Hammer the 'security bolts' on an angle so they will start to unthread. Once you get past a certain point, you can remove them by hand. Ford put locktite on the threads. When you put the new one in just run 1/4x20 bolts and lock washers to hold in the switch.

you can either go john style on it or get a set of security torx bits from harbor freight, ha. IMHO theyre good to have in the toolbox.

either way be sure to change your ignition to the revised part to prevent spontaneous combustion.

[gadget73]

Not all of them have security torx. The originals on my 86 were this strange headless bolt that I had to use a special socket designed for removing rounded off fastners to get it out. A chisel would work too but the column is largely aluminum and you really don't want to deform those holes if you don't absolutely have to. Whack it wrong and you could bust a chunk out of the column and then you're kind of screwed.

[86VickyLX]

Not much force needed to get those bolts going. Once you get a nice indent in the head, then you can start putting a little more force in your swing. But like I said, it doesn't take much.

[Mainemantom]

I replaced the switch recently. I will check it again. As far as taking the bolts out, I used a hacksaw to make a groove. Then the screw driver fit well so the bolts came out.
This problem has been going on for years. I have owned the car since 2001. The previous owner had the problem, that is why the jumper wire was installed. The last incident of it shutting off when making a turn across traffic really got my attention.

[gadget73]

Check the connector for the crank sensor. I think its somewhere right around the front corner of the intake manifold. If that flakes out, you lose spark and it will not start again. I'd also pull and clean the connections at the Duraspark box and at the CFI unit just to rule that out. Could also be worth just unplugging each connection one by one, spraying some contact cleaner in each, putting in a bit of dielectric grease, and re-assembling them. It really sounds like a bad connection or broken wire somewhere that randomly flakes out.

[sly]

Check the connector for the crank sensor. I think its somewhere right around the front corner of the intake manifold. If that flakes out, you lose spark and it will not start again. I'd also pull and clean the connections at the Duraspark box and at the CFI unit just to rule that out. Could also be worth just unplugging each connection one by one, spraying some contact cleaner in each, putting in a bit of dielectric grease, and re-assembling them. It really sounds like a bad connection or broken wire somewhere that randomly flakes out.

+1

[fmansfield444]

I have security bolts on my van and not sure about the CV. I have the security bits but I've just always been fine with a zip tie, never any fires for me.

Ha my dad actually fixed one before by stuffing a rag in the shroud against the switch.

But yeah these guys know more than me so listen to them