My engine keeps running after I turn it off.

My Pertronic ignition died after hooking up the adapter for the tachometer. It was working for a while. But as I was tuning the carburetors the engine stopped running and wouldn’t start again.

I disconnected the MSD and the engine still wouldn’t start. I put the points in and the engine started. Then I hooked the MSD and the engine started again. But when I turn off the key the engine keeps running

Has anyone had this problem before?

The power to the points/MSD is an original wire from the engine relay board. Should I run a separate wire from the ignition key?

only if you like burning your car to the ground ...

i suspect the ignition switch. you'll fry your pertronix if you leave the key in the "ON" position.
sounds like you got a faulty switch that is stuck in "ON" which would explain why the engine keeps running and why the pertronix fried ...

got another switch you can try?

Andy

My car was doing that when I had the timing at idle very retarded. Since you were changing stuff out it's a possibility.

Power is leaking back into the system is keeping the MSD energized, a one way diode spliced into the the blue alternator wire either before the regulator or the wire running to the alternator light in the dash should solve it.

BING BING BING... we have a winner!

with Aaron.

Common problem... check the MSD troubleshooting info