Help!...won't shut off!

[chevyf16]

Finally got this thing running well, and now it won't shut off!!

carb, electronic ignition, hi torque starter (2 wires), 2150 with electric choke, but other than that it's a stock 74 with a 351.

Problem doesn't happen everytime, but about one out of five times, the key wont turn the engine off. Is my problem in the ignition switch??

 

[Revelation]

Sounds like the Ign. Switch not killing power to the Ign Run.

 

[Broncobowsher]

I take it you just turn the key back on and off again and it will stop. That is generally a bad ignition switch.

But I do see another possibility. The new starter, 2-wire. How did you wire that up? More specificly I am interested in backfeeding the "I" wire off the original solenoid. Probably not the problem, but it can be related. Especially if you did some interesting wiring of the starter.

 

[chevyf16]

starter wired per the included instructions.

+ from battery connected to + on fender solenoid, then to starter (always hot)

other side of solenoid to other connector on starter (smaller wire)

 

[chevyf16]

as far as the key turning it off (or not)...when it doesn't work, it never works.

Meaning, when the key won't turn the engine off, the only way I've found to kill it is to choke it off with the clutch. I know that's not good, but running out of gas will take forever!

 

[Broncobowsher]

starter wired per the included instructions.

+ from battery connected to + on fender solenoid, then to starter (always hot)

other side of solenoid to other connector on starter (smaller wire)

Thats correct.

OK, down to 2 possible problems. bad voltage regulater back feeding the igntion (forgot about that before) or bad key switch.

As for stalling the engine out with the clutch and walking away, probably the best way to stop the engine but there is probably still an electrical draw that will kill the battery overnight.

If you are going to walk away from it for the night, unhook the battery.

You can also try unplugging the voltage regulater and see if the ignition sticks. You won't have a charging system while unplugged but it will eliminate the potential backfeeding. Except for one instance don't plug/unplug the regulator with the engine running. That one exception is when you have played with it enough that you are sure that is what the problem is. In that case, with it stuck running, unplug it. Unplugging it while running will likely spike the regulater and kill it, but if you are sure that is what it is then what do you have to loose? When the engine dies as you unplug it you will know that is what it was.

 

[chevyf16]

you're exactly right on the power draw. I've had the battery unhooked for that reason.

Some more troubleshooting results:
looking at the front of the starter solenoid, the battery + is connected to the left side post, the starter wire is connected to the right side post.

The two front connections left over are starter wire on the left (I think). What goes on the right front? When I disconnect that wire (right front), the power drain stops. The wiring diagrams don't really show what that wire goes to, but on mine it travels into the cockpit through the bundle next to the voltage regulator on the firewall...what does it go to?

 

[chevyf16]

BTW, when I turn the key off, it does turn off everything else...ammeter, fuel level, radio, etc.

It just won't turn off the engine.

 

[beaux312]

I know this sounds weird but get a new starter solenode,had one go bad and the truck wouldnt shut off

 

[Lohman]

I've had it happen to me several times on Ford products through the years. It has always been the starter solenoid. I would almost bet it's your problem too.

 

[chevyf16]

Alright...I'm going out to put the old solenoid back on. I'll report back with results...

 

[Bucmaster]

I just picked up a pretty bone stock 77 last weekend. Runs great but is a lil rusty. Anyway, I've been messing around with it lately, driving it around the yard and such and its been working fine. All wiring is stock and not touched in at least 10 years. So I pulled it in the shop to start tearing all the rust off and low and behold, it wont shut off. Just like your problem. I tried the on off on off to no avail. Its an auto, so I pulled the pos off the battery thinking this would not kill it as the alt should keep it running. But it did kill it. So I walked strait into the house to search "won't shut off" and this is where I came to. Lucky me I guess. I'll let you know if I find anything too. Thanks guys.

 

[Broncobowsher]

BTW, when I turn the key off, it does turn off everything else...ammeter, fuel level, radio, etc.

It just won't turn off the engine.

That makes sense. Those are on the accessory circuit (not the amp, but the rest of them). The ignition circuit on the Bronco is very limited. The ignition, via the ballast resister with a sub feed off the "I" post on the solenoid to bypass the ballast resister during cranking. The only other thing on the ignition circuit I can think of is the voltage regulator. And the ignition switch itself.

 

[Bucmaster]

Fixed mine. It was the starter selenoid. As a quick check, with everything hooked up, engine running and key OFF. I unplugged the brown wire on the starter selenoid and it killed the motor. Plugged it back in and drew a fairly large arc picking up the wire and windings.

 

[chevyf16]

Fixed!

Put the old solenoid back on (the 1974 original) and it works perfectly. The new solenoid was the problem.

Thanks for the help...again.

 

[miikee73]

Fixed!

Put the old solenoid back on (the 1974 original) and it works perfectly. The new solenoid was the problem.

Thanks for the help...again.

Now if you can get your money back for the new one. electrical is hard to return.