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

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.
 
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?
 
Bumping and asking if there is a tight and loose specifications on Torque Converters? If not what makes them tight or loose?
 
Did anyone mention too hot or wrong plug
how do your plugs look
 
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.
 
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?
 
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.....
 
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……
 
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.
 
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.
 
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