Car will not shut off?
 

1968 A-Body HEI. Took it for a drive and was getting back on the freeway and punched it of course and I smelled something burn for about a second so I pulled over and my cra would not shut off? I drove it home ( short distance ) and pulled the alternator wire and it shut off. I replaced the ignition switch and it started but again it would not shut off. Could this be inside the distributor? ( coil? ) What would you guys try next? Could my tumbler be bad? ( I doubted that theory because it wouldn't start either?) Thanks again James

Are you using an MSD box?

If you pulled the connector out of the alternator and the engine shut off, the alternator is bad -- it has a shorted diode that's allowing current to backfeed into the ignition circuit.

Check this link, you may need a Diode. http://www.madelectrical.com/catalog/alt-1.shtml

And...
 

April 1971 I had this happen and it was the the wrong sleeve that the hot wire goes to the starter from the battery. It had gotten against the exhaust manifold and shorted out. Took it to a dealer as I was 1500 miles from home and and he diagnosed it and had it fixed under warrenty. Replaced wire and wire sleeve. Check it out. Does alt lite/guage stay hot? My idle just slowed down. Had to let out clutch to kill engine with brake on. Disconnected hot battery cable for the nite.

This just happened to me and it was the alternator that was almost new when I got the car.

WOW! This could be an easy one! Let me check it out. Thanks again!

Since it's a "A" body, the likelihood of the ignition feed wire at the solenoid shorting to the battery cable is low. (there is no ignition wire there in a OEM harness)

Most likely is the leaky diode in the alternator, or the use of a MSD box without the blocking diode. Check to see if some harness wiring was burned or melted also.

George

I had a similar problem when I put in a high amp alternator. I pulled the ground cable and it still kept running. I killed the fuel pump and about a minute later (I was laughing the whole time, gas was only $2/gallon then) it shut off.

I had to add a diode in the wire going to my idiot light for the alternator. That fixed it.

Ditto to what Karch said.
It fixed the same problem you have.