Truck won't shut off
 

Truck has HEI wired to IGN unfused at fuse box. When I turn the key off it runs for another 5 to 10 seconds then shuts off.

its not runnin too rich and just dieseling because of that is it?, my radio keeps playin for 3-5seconds after I shut it off, itswired to acc fused
Bryce

Advance the timing a little and see if that fixes it.

Do you have an electric fan? I know my truck has trouble shutting off when it's on. I'm getting around to fixing it soon.

I have ALL OF A SUDDEN developed this problem and I just recently installed electric fans. The fans and HEI are sharing the same power plug on the fuse box.

Hmm I wonder

BTW its not deiseling

The electric fans will do it. Distributor and electric fans must not be connected in any way.

Please explain the logic behind all this. Are the fans holding enough charge to feed the HEI for a couple of seconds? My truck did the same thing a while back when I converted to HEI. After changing the resistance wire so the HEI could pull 12 v I had no problem. I still don't understand what was holding charge then.

After you turn the ignition off, the electric fan doesn't stop spinning immediately. For the 10 or so seconds it is still spinning, the fan itself is acting as a generator, feeding energy back up to your ignition system.

This Cartalk Puzzler explains in more detail.

But to generate that much power amazes me. Well I guess it isnt really all that much. An electric motor works with magnets on the outside with a commutator in the middle. An electro magnet is created in the center pulling the comm around. Now the generator has electro magnets on the comm and outside correct?? interesting none the less...

Aye, it confuses me as well. I'm gonna have to try it when I get an electric fan.. :D

It could be a problem with your alternator, like the diode trio. disconnect your ammeter/volt meter and see if you still have the problem, they can supply voltage to the engine through the guage and keep it running.

GMCJunkie's hubby's truck is doing the same thing, and he says it is the electric fan. He showed this to me last weekend when I went out to pick up the rear A/C parts for a suburban.....

Its true, the fans will do it. At an idle, it only takes about 4 volts to fire the ignition....way less if you still have points. The fan(s) can, and do produce this kind of voltage.
John, you are one lucky b@stard.:(

Thanks Guys!!!!!

It was the electric fan, had it wired into the hot to distributor.

Its either running too rich or your idle is set too high. Knock it down a little and see if the problem persists.