Engine "dieseling"

Posted By: Merlin45

Engine "dieseling" - 10/26/10 05:32 PM

I have a 440 6 pack in my Challenger and every now and then when I shut the engine off the engine wants to chug/run, a condition I've heard called "Dieseling". When this occurs, what exactly is happening? It amost sounds/feels like my engine wants to run backwards, just makes me cringe when I hear this. This doesn't happen often but have a good idea it's due to the crap fuel that's available. What causes this to happen: poor fuel, hot engine, carb setup, etc: Just looking for comments so I know more about this condition. Other than that she can be a terror on the streets. Thanks.

Posted By: YO7_A66

Re: Engine "dieseling" - 10/26/10 05:54 PM

Dieseling can be caused by too low of octane, too high of an idle, and heat range of the spark plugs being too high just to name a few.

Posted By: MoparforLife

Re: Engine "dieseling" - 10/26/10 06:14 PM

most common cause is too fast an idle speed.

Posted By: MLR426

Re: Engine "dieseling" - 10/26/10 06:15 PM

Fuel is a major culprit.

loagn426

Posted By: MLR426

Re: Engine "dieseling" - 10/26/10 06:17 PM

Quote:

most common cause is too fast an idle speed.

Which means its on the main jet and off the idle curcuit.

logan426

Posted By: Crocker

Re: Engine "dieseling" - 10/26/10 06:32 PM

Quote:

I have a 440 6 pack in my Challenger and every now and then when I shut the engine off the engine wants to chug/run, a condition I've heard called "Dieseling". When this occurs, what exactly is happening? It amost sounds/feels like my engine wants to run backwards, just makes me cringe when I hear this. This doesn't happen often but have a good idea it's due to the crap fuel that's available. What causes this to happen: poor fuel, hot engine, carb setup, etc: Just looking for comments so I know more about this condition. Other than that she can be a terror on the streets. Thanks.

Do you have an idle stop solenoid on the center carb? This precisely what they are used for. It hooks to the 12v engine "run" circuit, so it actuates a tab on and around the curb idle and opens the butterflys a little at run idle, then when the ignition is shut off the throttle plates close preventing run on or dieseling. They were standard on the Aar T/a cars with the 3x2 bbl set up. Not sure about the 440 6 bbl.

Posted By: terzmo

Re: Engine "dieseling" - 10/26/10 06:34 PM

leave it in gear when shutting off...or ride the clutch a bit to drop the idle...if it stops properly then(shuts off)...lower the idle

Posted By: Barry70GTX

Re: Engine "dieseling" - 10/26/10 06:43 PM

Usually it can be fixed by adding more initial timing and closing the throttle blade.

Posted By: Merlin45

Re: Engine "dieseling" - 10/26/10 07:01 PM

No, I don't have the solenoid set up. I've seen them on plenty of pictures but do not have one on my engine. My idle speed is set nicely, to me it doesn't seem high at all and I always run premium fuel. Is there any harm in leaving the car in "D" when shutting the engine off? I've heard that done many times but am hesistant to do that.

Posted By: Hotwheelsjr

Re: Engine "dieseling" - 10/26/10 08:50 PM

Quote:

No, I don't have the solenoid set up. I've seen them on plenty of pictures but do not have one on my engine. My idle speed is set nicely, to me it doesn't seem high at all and I always run premium fuel. Is there any harm in leaving the car in "D" when shutting the engine off? I've heard that done many times but am hesistant to do that.

No harm at all. Have to do it in my daughter's '67 Bcuda all the time. Once you get used to it, it's just second nature.

Posted By: Mopar_Country

Re: Engine "dieseling" - 10/26/10 08:57 PM

Quote:

Is there any harm in leaving the car in "D" when shutting the engine off?

No.