Does anyone have any advice or explanation why my engine continues to run for a couple seconds after I turn the key off. It has MSD6AL and MSD Distributor. Engine is new GM383. The hotter it is outside the longer it continues to run but no more than 4 seconds before finally dies. Any help appreciated..... :hurray:

Throttle blades are too far open at idle. Typically this can be resolved with more initial timing then adjusting the idle down. Some cars use a solnoid that activates when the engine is running and holds the throttle blades open some at idle then lets them close when the engine is turned off...

I currently have about 32 total. 20 + 12 at the damper Sound low?

Do you have the diode installed in the wire going to the charging lite? Look at page 8 of the MSD instructions.

Throttle blades are too far open at idle. Typically this can be resolved with more initial timing then adjusting the idle down. Some cars use a solnoid that activates when the engine is running and holds the throttle blades open some at idle then lets them close when the engine is turned off...

DJD is heading you in the right direction!!!

idle to high..idle mixture... and maybe timing

Thanks for advice - My idle is currently at 850 rpm with a standard tranny is this too high?? Also re: msd comment - I converted to a 1 wire alternator so shouldn't need this diode anymore as I understand.

Thanks for advice - My idle is currently at 850 rpm with a standard tranny is this too high?? Also re: msd comment - I converted to a 1 wire alternator so shouldn't need this diode anymore as I understand.

If it will idle at 700 rpm I bet your problem will go away. If your cam requires 850 rpm to idle them try a couple degs more initial timing, the idle will go up and you can close the throttle blades some to bring the idle back to 850 rpm.

Appreciate your recomendation - I'll give it a try but have feeling your correct. Currently have 32 total w/12 initial. If I raise my 12 to say 14 do you think I should change distributor so totals 32 (this is what GM recommends for total at 3,000rpm)

I would also recommend post #4, about the diode in charging circuit as well as curb idle .

I'm not really up on MSD but if the diode was the problem I don't think it would turn off at all.

Bill - I would up the initial by 2 degs and see how things go with the 34 total. I run 34 total in my 383 and have no pinging problems. It's not a GM crate but it has a retrofit roller cam and rockers, about 9.87:1 compression and makes a lot of power down low. Anyway both suggestions I made are 10 minutes max to try and a good test run, make sure the engine is at operating temp when making adjustments. Oh and don't do like I did, I pulled my vacuum headlights off the manifold to re-route the hose and forget to hook it back up. ran crappy as hell with a big vacuum leak and it ran on something awful.

I'm not really up on MSD but if the diode was the problem I don't think it would turn off at all.

Bill - I would up the initial by 2 degs and see how things go with the 34 total. I run 34 total in my 383 and have no pinging problems. It's not a GM crate but it has a retrofit roller cam and rockers, about 9.87:1 compression and makes a lot of power down low. Anyway both suggestions I made are 10 minutes max to try and a good test run, make sure the engine is at operating temp when making adjustments. Oh and don't do like I did, I pulled my vacuum headlights off the manifold to re-route the hose and forget to hook it back up. ran crappy as hell with a big vacuum leak and it ran on something awful.


I will try this tonight. Thanks for your help and appreciate the recommendations. Yes, those darn vacuum operated headlites (cool as they look - have to admit can be a pain at times) Possibly a good aftermarket product would be to make/sell a cover similar to 69 RS headlite cover that would allow a window for light to pass throug in case of malfunction - obviously not intended for the purist which I'm obvioulsy not.

Turns out the run-on condition was a result of the idle being set too high. It was about 850rpm and I lowered it down to 760 RPM - problem solved. Thanks for the Help!!!

Thanks for the follow up Bill, Happy Cruzin!:cool: