Jeffro07

I have a 6.0L LQ4 with T Rex cam 1/78 headers th400 4000 stall and my question is how much total timing should i be running? how much at idle? (1k rpm) I have 32 degrees total and 18 at idle and the car runs good and pulls strong. Its loud so i dont reall hear any detonation, but when i shut the car off it diesels and takes a couple seconds to shut down? any imput would be greatly appreciated! thanks in advance

Keith_D

Go and look in the carbureted forum.

S10xGN

iTrader: (11)

Dieseling is usually poor quality fuel, but can sometimes be "crutched" with additional timing...

BigEd_72455

iTrader: (7)

try a full tank of premium unleaded, and look for a station that advertises NO ETHANOL in their gas.

all this blended crap is playing heck on our delicate fuel systems!!

Fast86z

iTrader: (1)

Disesling can be caused by a few things actually. Is this a carb engine? Ususally caused by throttle being too far open at idle causing engine to suck in air and fuel after ignition is cut and is ignited by hot combustion chamber. Also called "run on", and can be caused by crappy fuel too, but some people will also say too much timing at idle. That doesn't make a lot of sense though since your engine should kill the ign at key off. A hot spot in the combustion chamber along with air and fuel will make it diesel. Some cars from the factory even had silenoids that closed the throttle completely to try to bandaid this problem.

My old setup dieseled occasionally when key-off, and I got it better by adjusting the carburetor so that the front and rear throttle blades were cracked open an even amount, and the primaries were not hanging open. Never did completely fix the problem though because it would still do it occasionally. Better quality fuel helped too. Never caused any problems though, just anoying.

Good luck.