since i've built my engine i have had an engine dieseling problem on shutdown, i cant seem to nail it down though. i am running 9.85 comp, alluminum heads, 160 degree thermostat, flex fan, it never goes over 160 degrees. i pass emmissions. it seems like the engine is flooded but only slightly on restart. the problem seems to only occour after the engine runs at a higher rpm for a few minuts, like if i shut down right after pulling off the parkway ( every morning on my way to work). i get physically ill every time my 5000 dollar engine does this, please help.

 

I know two factors to look at is timing and idle speed. Both can lead to run on. I have to shut mine off in gear to keep that from happening and I have everything good as far as temperature and timing. And I don't think my idle speed sis too high.

 

it idles at about 1000 rpm, since youy brought up timing, i have a hypertech chip from the stock lg4. i have about 36 degrees total, but i don't know what the idle timing is. i recently backed it down 4 degrees to the stock spec, with no difference

 

Get you idle speed down, I bet that's your problem, next time shut the car off in D and see if it shuts down ok.

 

its a stick, i can load the engine and stop the run on, but i shouldn't have too

 

Correct, but by shuttin it off in D or what not, it will keep the rpms down, and if it works like this, then too high an idle will most likely be your problem.

Be sure you're timing isn't too far advanced.

 

I run into the same problem, its most likely your idle speed. It may be that you are running a little rich. Try shutting down the car quick when you go into park before it has a chance to come up in idle. Lastly, double check ur timing and spark plugs. Make sure your plugs match the heads. I had a huge problem because the plugs were from my old motor and they were not the right ones for the heads. Do not overlook this, by changing my plugs i gained 1.3 sec in the 1/4 mile. Timing should be between 8-11 initial and about 36 at 2500RPM. good luck

 

hmmm idle speed must be why mines doing it. I idle at 2500rpm in N and P?!? Maybe I need to check my carb gasket and vaccum lines because something is wrong. Probably need to set my idle miture screws to. Other than that it seems to run decent. starts right up without being pumped and without a choke in 40 degree weather. Starts hella easier than the TBI did....plus so far it has WAY more power than the lo3. i havent even got on it at all yet because i have longtubes only and its way to loud to get on it. I think my timing may be off to I have some popping from the exhaust bu t they could be because i have no backpressure...Ill find out tomorrow when i get exhaust on it.