Engine Keeps Running After Shutoff
 

My car originally was a 2.8 and electrical wise it ran fine, but now with my 327 and MSD 6A Box whenever I turn the key off the engine continues to run for 3 seconds. I put a diode in the alternator line and that didn't help. Any ideas?

Thanks

Excessive carbon build-up or very high operating temperatures can cause this. Sounds like your engine is relatively new so it's probably not the carbon build-up, but I thought I'd say it anyway.

Had a similar problem when I was running my fans off of my ignition switch. The fans would be rolling, then I'd shut the car off and the fans continously turning would keep the ignition running until the died down slow enough that it wasn't sufficiant enough for the ignition system to function correctly. Granted you prob don't have this problem but it is a suggestion to relate to.

The engine has less then 200 miles on it. Its not due to heat because if I turn it on then turn it off 10 sec later it still takes about 3 sec to shutoff. I have an electric fan. I didn't wire it in so I have no idea what its running off. I'll have to run the fan idea by my neighbor since he's a master mechanic and see what he thinks:p

When I get my second perma cool fan in I'll have 5900cfm. So no worries about cooling.


Any other ideas?

What happens if you shut it off in drive? Whats the method of fuel delivery?

What is the ignition timing set at and what is the idle speed in park?

Its a manual. My idle speed in neutral is 1000. Sorry I don't know what the timing is set at. My fan is actually running off my ignition switch so maybe what BIGJON said is whats happening. Tomorrow I'm going to disconnect my fan and then try to shut the car off to see what happens.

Thats it!

Sadly enough I made this mistake once and will never again do it. But anyways I am almost sure thats your problem.

Hope ya get r dun :D