ZONES89RS

iTrader: (25)

Yes captian obvious. When you cut EFI the enjectors stop fuel flow. A carb does not. It always comes down to lean cylinders at idle to be hot enough to have a spot causing fuel to still ignite. Mine does it on 87 but not 89. The 87 burns hotter.

tennerv8

iTrader: (7)

Hit a nerve there?

ZONES89RS

iTrader: (25)

Was just funny. Pretty simple to understand. Lol

331camaro

iTrader: (1)

i think someone dosent like efi! my old gen 1 sbc would desiel only because of the wrong octane, trying to cheat, and high idle conditions. shut her down in gear when your idling over 1200 ish, keep backing the idle down till it goes away, and like zones mentioned, might be an octane issue as well

onefast84

I had problems with mine with the other heads, tuned it, and got it to stop. Now I have the problem again. I believe its mostly carb related, but sometimes you have to get the timing just right to get the carb right. I am going to test this theory when weather here in MI gets warmer. This is a great thread! I thought I was the only one having this problem!

Pop N Wood

iTrader: (1)

My a 79 Ford Fiesta had a Weber carb with a solenoid in the idle circuits that cut off the idle circuits when the key was turned off. They got rid of high octane gas back in the 70's so this was one method of dealing with it.

Any build up in carbon in the combustion chambers will make the problem worse. This can lead to hot spots which ignite the fuel mixture.

So put those two things together and understand that if your idle mixture is too rich then you are sooting up the combustion chambers and providing a nice, rich fuel mixture, both of which will contribute to the dieseling. A mis adjusted choke will contribute to the problem. Back in the day we use to go out on a high speed run to "blow out the carbon". At least that is what we told ourselves.

If your car diesels then switching to a higher octane gas will almost certainly fix it. If you can't get that then leave it in gear when you turn it off. Flooring the gas pedal can help stop the run on too.

Doug G

Mine did it recently...engine run on....backed down initial timing...all good now (carbed)

ZONES89RS

iTrader: (25)

Nope 331camaro, no problem with efi. Could care less. I do take offense to the retards that dog carbs yet have never touched one.

331camaro

iTrader: (1)

Ya most guys who rag on carbs know nothing about em

onefast84

In the carb section non the less

ZONES89RS

iTrader: (25)

Yep. Then they wanna know why I get a bit fowl with them.

tennerv8

iTrader: (7)

I wasn't ******* carbs if I was what you were referring to. I was just sharing my experiences with both systems.

ZONES89RS

iTrader: (25)

Nope, not you. You have been nothing but a carb member to this section. A contributor.

89gmcs15

iTrader: (7)

Bumpin this back up. Got my junker pulled out of the snow fort it built for itself through the winter. Well after messin with the carb a bunch again and then re doing it on the engine it still wanted to diesel. Even with fresh 91 gas in the tank. I got frustrated and pulled out the computer to mess with the timing. Set it @ 30* at idle and bumped the idle to 1000 in park and 14.5 afr both in gear or park. Run the engine all day or even just to warm it up and it shuts right down without issue. I have a issue now where the carb goes dead lean before the jets kick in. I think my idle feed restrictors are too small now or maybe I should start playin with the air bleeds. It runs good at wot and idle and cruising speeds, just putting from a stop it gives me trouble. Just a recap, I think the timing change fixed the issue but I can't say totally the better gas didn't help either. Ill run it out and put 87 octane in it and see if it diesels I guess