Reply to "Engine is dieseling badly on shutdown - Seeking advice"

It is important to note on this posting that all Panteras came with vacuum advance and that ignition timing is set with the vacuum canister disabled. As John Taphorn mentioned, timing advance is normally set at 16 degrees. If you check the timing again after reconnecting the vacuum canister you will see that advance is much higher, probably in the low to mid twenties at idle. I spoke with Progression Ignition about this a while back and they said their software does not automatically emulate this characteristic. They said if you want such just go back and add eight degrees to the first two columns in the table except for the ones that support startup (those remain at 10). It was not until yesterday afternoon that I made this adjustment and the dieseling stopped. This particular engine requires the extra the advance normally supplied by a stock distributor to avoid dieseling. I have worked on other engines that did not diesel with the default table. It is now apparent to me that eight degrees should be added to the default table idle columns when using this distributor. I think Progression Ignition software should have a check box labeled “Include vacuum advance in idle columns” and it should default to yes.