Causes of engine dieseling or run on.....

[69a100]

Other than Ether whats a good spray for looking for vacuum leaks?

WD-40, Gumout, brake-cleaner, anything that's flammable will work. Good Luck

 

[Don Frelier]

Sounds like you need a looser torque converter.

 

[Demonic]

Your converter is way too tight. What carb? I would drop the idle to 1000. If you can't get enough air at idle I'd drill a .050" hole in the primary throttle blades.

 

[niteshift92]

Other than Ether whats a good spray for looking for vacuum leaks?

Regular spray carb cleaner. Idle will drop significantly. May die if the leak is bad enough.

 

[Moparfiend]

Regular spray carb cleaner. Idle will drop significantly. May die if the leak is bad enough.

I don’t think its a leak but I’ll check it out.

 

[Moparfiend]

Your converter is way too tight. What carb? I would drop the idle to 1000. If you can't get enough air at idle I'd drill a .050" hole in the primary throttle blades.

Its a mechanical 4150 650cfm How is the tightness or looseness specified in a TC? Or is it related to the stall point?

 

[Moparfiend]

Bumping and asking if there is a tight and loose specifications on Torque Converters? If not what makes them tight or loose?

 

[wyrmrider]

Did anyone mention too hot or wrong plug
how do your plugs look

 

[matthon]

I have a 318 2 barrel that will diesel on a bit, but if I just let it idle for 30 seconds once parked it shuts right off.
I've set everything correctly and checked multiple times.

It's no big deal to wait 30 seconds.

Not sure if this adds anything to the conversation.

 

[Don Frelier]

Loose means a higher stall speed but even between manufacturers that number varies.
But my guess would be 2,000 -2,500 for your setup.
Someone here will know way more than I.
What gear ratio is it?

 

[Moparfiend]

Did anyone mention too hot or wrong plug
how do your plugs look

Plugs look fine. I just replaced them with a cold or plug to see if I can get a little bit more advance. Went from an auto light 65 to an auto light 63 which correlates to the champion plug for 1970 340 with higher compression. Haven’t run it on the new plugs yet.....

 

[Moparfiend]

Loose means a higher stall speed but even between manufacturers that number varies.
But my guess would be 2,000 -2,500 for your setup.
Someone here will know way more than I.
What gear ratio is it?

355 gears so the tightness is a function of Stall? Is it linear is an exponential does it vary from manufacturer to manufacturer what’s the actual mechanism that affects it? Curious minds want to know……

 

[Demonic]

Your speed drop between neutral and gear makes me thing of an vacuum leak as others have mentioned.

Torque converter stall speeds are not a hard number. The more torque you put into it, the higher it will stall. There is a rating for some aftermarket ones known as the K factor. Multiply the K factor times the square root of the applied input torque.
From Tom Hand's excellent book on the Torqueflights. - Stall Speed = K x _/ applied input torque. Long story short, most factory converters have too low of a stall speed. May not be your problem.

 

[wyrmrider]

Too low a stall speed?
Inadequate low speed torque

 

[MoparDanMan]

I have to kill my car (automatic) in gear lest I get dieseling. Wondering what might be causing this. I know its prevalent in high perf motors and I assume its due to high compression. If it is the high compression what is the mechanism that causes it? Is it just temperature and pressure?

Why does killing it in gear solve the problem? Is it just the load on the inertial force?

High compression, to much timing advance, carbon deposits, float set too high, bad gas.
And yes the engine has a load on it, but I've seen a Charger that was dieseling so bad that you could drive it with the ignition off, but it didn't run well.

 

[bigbother14]

I had the same problem when I first bought my Road Runner. Had to start to let the clutch out in gear after turning the key off or it would run on forever. I plugged a vacuum line into one of the vacuum ports at the base of the carb and stuck the other end into a glass of water and ran the engine at about 2000 RPM until the glass was empty (doesn't take very long). That cured the problem immediately and it has not dieseled since. Obviously this water injection procedure is for carbon build up in the cylinder. Works like a charm if that is your problem.

P.S.
Be sure the engine is at operating temperature when you do this.

Hello I have the same issue on my 68 rr if you can text me at 224 304 3662 I have a few questions if you don’t mind