Topic: ignition not turning off when hot

[medicman]

I have a small problem. The car has no interior and the dash is out. I started up the car and when it is cold the car shuts off by the key. If I let the car warm up for a couple of minutes, the car will not shut off by the key, it just keeps on running. Could this be  ignition block problem or is this a simple fix due to the dash not being installed.

If it helps with a solution, the car has been in the body shop for the last year and a half so there has been multiple layers of dust through out the electrical system.

This is bugging me, it never did this prior to the body shop.

Thanks,

Medicman.

[eroc022]

is it dieseling ? or is it not turning off at all? dieseling is running for a few then turning off, if thats the problem its in the ignition system, if its just not turning off, it could be either in the ignition switch or the underhood components.....

[Tin Indians Rule]

Yeah I was wondering that too, Evan. I mean it may be as simple as the timing too high. He could try shutting the switch off with the transmission in drive and usually if it's the timing it'll pull it down enough to shut it off.

[medicman]

Nope it's not dieseling, car will run for ever. The only way I get it to shut down is to put a rag over the carb and choke it out. I have never encountered this kind of problem before with any car so it has got me stumped.

[ta78w72]

Could be the ignition switch.  Did you check the motion on it?

[medicman]

what do you mean by motion?? The key cycles from acc to crank no problem.

I went out today because I had to set up the choke on the holley carb (sent it for a cleaning and it came back with the choke cam spring not hooked up) Anyways, I had to start the car to see if everything was ok and the choke now works perfectly, but now the car will not shut off even when cold.

I do notice a very slight stumbling action from the engine when at high idle (like it wants to shut off) when in the off position and smooths out when back in the run position. If the car is idling low enough the engine will shut off under 1 minute.  You would almost think it was dieseling but dieseling shuts the car off in a violent fashion the longer it diesels to a stop.

This engine is a fresh from pan up, it was put in the car and set up perfectly, again I have only noticed this problem since it came back from the body shop.

[kc79ta]

Wow, that's weird. Seeing how the dash is out I would try blowing out the ignition switch (not the key tumblers, but the switch down on the column). I would think if there was dirt in there it would not start or crank at all, but it's might be worth a try. And make sure it's tight as long as your cleaning it out.

[medicman]

I was wondering if there is a ground off?? The dash was removed at the body shop. Is there a ground under the dash that needs to be connected to allow the engine to shut off??  Could it be dirt in the ignition switch?

[kc79ta]

I don't think a ground wire or lack there of would do it. The switch in the run position simply puts 12 volt to the coil, and when turned to off breaks the circuit.

Don't know about dirt, but it's something to try.

[RENOVATIONS]

Could be the ignition switch.  Did you check the motion on it?

I'm with Russ...check the switch and the motion/movement of the linkage

[kc79ta]

I think Russ and Jeff are right. Maybe the body shop moved the switch out of position and the linkage is not pulling the switch to the off position. When you turn it to off you can pull the key out and it stays running. What happends if you turn it  fully back to the acc. spot?

[medicman]

turned to the acc. spot it still runs.

As I indicated earlier, I do notice a very slight stumbling action from the engine when at high idle (like it wants to shut off) when in the off position and smooths out when back in the run position. If the car is idling low enough the engine will shut off under 1 minute.  You would almost think it was dieseling but dieseling shuts the car off in a violent fashion the longer it diesels to a stop.

Is it possible to bench test a ignition switch?? Maybe that would rule it out.

[ta78w72]

Connect an induction timing light when it's running with the key off to see if you're getting a spark.  That will tell you if you have an ignition problem or a dieseling problem.

[medicman]

Thats a good idea, never thought of that one. I am going to pull my steering column out of the car to paint it factory black. While I am there I am going to change the ignition switch at the same time. They are only $15.00.

Once I get it back in, I will try the timing light idea. Will get back to you and let you know what happens.

Cheers.

[medicman]

Ok so here is where I am up to.

I put he column in the car with a new ignition switch and still the same thing. I took a look at the alt and unplugged the two pin plug on top and the car shut off. I left it unplugged and the car starts and shuts off perfectly.

I put a test light on the two plug and the heavier wire has constant feed with the ignition off. I know that is not right, it should be ignition fed only.

So I am wondering why that would be happening. What is causing the constant feed?