engine and drivetrain Engine runs for 15-20 sec after turn off with key out!

[mtriple]

The only thing that was replaced was the distributor. specs:

side drafts

85 amp alternator

electric ignition (it is the IE distributor brand new unit)

MSD ignition

Red Coil

What in the world could cause this??

TIA

hamada

[Denis]

Your timing is waaaay out! When I brought mine home it was set at 10 deg at 2500rpm and "dieseled" for about 5 seconds. Scary

I cleaned the carb, nada, set the timing and fixed 1 vacuum leak, problem solved.

If it still does it, you will need the M20 repair

[Preyupy]

Are you running an electric fan? If so depending on how you have it wired it could be acting like a generator when you turn the key off and supply just enough power for 5 sec or so to keep the ign system working.

[conkitchen]

Are you running an electric fan? If so depending on how you have it wired it could be acting like a generator when you turn the key off and supply just enough power for 5 sec or so to keep the ign system working.

Interesting thing you say Byron, Great Scott!

So; if I have a big enough fan wired into my ignition system I could run the car without the HP drain of an alternator. Provided I go fast enough to keep the propeller spinning. Might even be the solution to perpetual motion.

Hmmm,

[LimeySteve]

If it has an electric fan it can back feed the ignition & make the engine run on , I believe a resistor is needed on the ground side of the fan to prevent this happening.

[Preyupy]

Not a resister but a diode would do it. I have also seen a couple of cars that would run on just for a sec or two if the heater fan was on high.

[allbim]

So; if I have a big enough fan wired into my ignition system I could run the car without the HP drain of an alternator. Provided I go fast enough to keep the propeller spinning. Might even be the solution to purpetual motion.

Hmmm,

Yeah, just hook that fan up to an electric motor, get that car up to speed and just keep on goen.

[flyingjolly]

So; if I have a big enough fan wired into my ignition system I could run the car without the HP drain of an alternator. Provided I go fast enough to keep the propeller spinning.

That's how backup generators on planes work - they extend a small fan from the fuselage. Just as a technical information

[mtriple]

I believe it was timed correctly. It drives excellent, but the engine insists it wants to run after I take the key and walk out of the car. 20 seconds is a bit much.

No electric fan and I believe the diod was replaced by indie trying to troubleshoot. Also ignition switch was replaced thinking it was faulty.

I've been in WTF world for a few weeks now...

[Simeon]

When was the last time you had the head off?

Could be that you have a load of carbon on your head / pistons / valves and that is glowing hot and giving its own ignition.

I think having your idle too high can exacerbate the issue since there is more stored energy in the flywheel.

[LimeySteve]

That is it , a diode, it was late when i answered that , we have had a few cars come in with the same problem, diode did it

[Preyupy]

Check for voltage at the coil when you turn the key off. If there is power there you need to figure where it is coming from. If there is no power then you have a problem with carbon build up, idle speed, plug choice etc.

[FunkyLaneO]

If you don't think it is your timing then check your spark plugs, if an electrode is screwed up it can heat up and act like a glow plug and cause the engine to diesel. It's not likely but possible.

[mtriple]

When was the last time you had the head off?

Could be that you have a load of carbon on your head / pistons / valves and that is glowing hot and giving its own ignition.

I think having your idle too high can exacerbate the issue since there is more stored energy in the flywheel.

the year before last year when I had the proper valve guides installed is when the head came off. Idle was set at 900 when I test drove the car..

[Guest Anonymous]

MSD ignitions, at least the older versions, came with a diode that was put into the line when you installed the MSD to prevent current leak back that made the engines run on after you shut off the ignition. My engine would run on forever without the diode so this is probably not your problem but it is an interesting quirk of the MSD system.

Have fun