I recently took my JK to the dealership for an oil change. I totally forgot to reset my CPU/superchips to factory settings before I took it in. When I got home, I turned off the ignition and took the key out but the motor kept running. I updated my CPU with a new flash from the superchips and it still runs after I get the key out. It runs for 3-5 seconds after.

Anyone else have this issue? Any idea what may have caused it?

 

The effect you're describing with a gas engine is called "dieseling." When a gas engine continues to run for a brief period of time after the engine has been shut off, it usually means you have un-burned fuel vapor present in hot spots of the combustion chamber. It could be because you're running low octane fuel with a tune that requires high octane or the new parameters you've set don't jive with the engine's design or current state.

If others who have your tuner can't provide some direction, I'd contact the maker of your aftermarket tuner.

 

Thanks. I'll make sure I didn't tune the wrong gas type and then go from there.

 

Ok.. So I verified that my tune is what it was before. I also put a new tank of gas. It still runs even after the key is out of the ignition. I can't find answers anywhere on what caused this and what can fix it. Anyone have any other idea?

 

I have always associated "dieseling" with carbon buildup in the combustion chambers.

 

I'll work the tuner again. Hopefully it was a "user error". Haha

 

Check your service invoice. It's possible the dealer pushed an updated factory flash to your PCM and it's causing a conflict. They automatically perform safety recalls and certain service campaigns on your vehicle (with or without permission) so there's s possibility the tech loaded a new flash. Doubtful, but possible. If they did, it will be noted on your invoice.

Before you cause yourself too much headache, you may want to get some input from the tech line for the aftermarket tuner. SOMEONE has encountered this problem with this tuner and found a solution.

Best of luck!

 

Have we moved away from the possibility of dieseling?

The impression I got is the system is just not shutting off for a few seconds.

 

Tune is back to factory settings. Still runs after the the key is off and out of the ignition.

 

If it started after coming back from the dealer, I'd promptly return to the dealer with a WTF did you guys do attitude.