Engine runs with key off.....

[Bonnewagon]

When I had a dieseling condition I found that shutting the motor off while in "drive" let it stop immediately, what with a load being on it. Then I found my motor tune was all messed up. At idle the throttle was open too much because the idle mixture was too lean. My timing was too advanced. My thermostat was stuck half closed. My THERMAC was stuck on "hot". I had a lot of carbon in the combustion chambers. I had to re-tune from scatch, checking even the simplest things. Then it ran well.

 

[Faulk21NG238]

Ok, looks like I have a lot of checking to do. Luckily I have a digital timing light, so I will look at the timing and the carburetor adjustment. Thanks for everyones help. Ill let everyone know how it comes out.

 

[pontiacgp]

did you read the troubleshooting in the instructions for the msd box?

Engine Run On
If your engine continues to run even when the ignition is turned Off you are experiencing engine RunOn. This usually only occurs on older vehicles with an external voltage regulator. Because the MSD
receives power directly from the battery, it does not require much current to keep the unit energized.
If you are experiencing run-on, it is due to a small amount of voltage going through the charging lamp
indicator and feeding the small Red wire even if the key is turned off.

: To solve the Run-On problem, a Diode is supplied with the MSD in the parts bag.
By installing this Diode in-line of the wire that goes to the Charging indicator, the voltage is kept from
entering the MSD.