engine will not turn off
 

Recently fired the engine in my 68 fire bird and all was fine except the alternator was not charging. Sorted that out, the field wire on the alternator was open circuit. Alternator now charges and engine starts fine but will not turn off at the key in the off position. I am running a HEI and have installed a relay that is driven from the old coil wire and new heavier power leads through the relay to the HEI. Any Suggestions.

Thanks:confused:

Maybe a stuck relay. Try using a 10 gauge wire from the fuse panel to the HEI that is IGN power with the key on. Sounds like you need a diode in the system to keep power backfeed from happening.:)

Does the car have MSD ignition? If my memory is correct, the ignition could be receiving power by backfeeding throught the brown wire on the alt, and it needs a diode installed.

If it's an MSD you need a diode at the voltage regulator. You can get one at Radio Shack.

The alt idiot lite circuit is backfeeding the ignition circuit as stated. This is common when using the relay to power the HEI. the backfeed has enuf current to keep the relay on. In a tradiitional connection, the coil itself would be in the connection and there is not enuf power supplied by the idiot lite circuit to keep the coil powered.

If you keep the relay, install a diode, (1N4001 thru 1N4007 available at Radio Shack) in series with the idiot lite brown wire, (terminal 1 on the alt plug), the band end of the diode towards the alt.

George