seraphim

Not sure what's going on unless the Shell V8 93 octane is no good. I've switched from BP cause I was getting the dieseling with it, but the Shell gasoline is doing the same thing. Is it the gas or the tune or something else? Any ideas would be much appreciated.

AmericanMuscle4.6GT

what do u mean by dieseling? stumbling?


try the 91 tune. could be bad gas.

ratnacage

Probably not bad gas from the pump since it's doing it from different locations, unless it's something screwy withthe way fuel is formulated in your area. It's probably the tune (too much timing).

seraphim

Ok, having done some reading it sounds like the correct term for what I'm experiencing is detonation. Has anyone had a similar experience with the JLTII and the 93 Tune? If the EVOLUTION guys are reading this, what should I do? Will you improve the tune or do I need to do something on my end. Any help is much appreciated.

moosestang

Detonation, from what someone told me on this site, sounds like shaking a tin can with a bee-bee in it. I'm pretty sure I was getting this with my 93 tune from brenspeed. I recently switched back to my 91 tune and haven't heard it since.

EskimoPie

Yes, detonation sounds very much like metal rattling around under your hood... if you hear it, get off the throttle ASAP!!! Continued throttle application w/ detonation can cause serious damage to your engine. Bad gas is a possibility, hot weather can cause it, but likely your tune has too much timing.

FYI, dieseling is when you shut off the engine but it keeps running anyway. Its the fuel in the engine lighting off even without a spark. It's pretty rare with fuel injection since once you shut off the key you're not intrudicing any more fuel into the cylinders.

PROMETHEUS PRIME

Try switching back to the stock intake and reflash to the stock tune and see if the problem is still there. If so then I would say its the tune.

MrSandman

Same here. Went to 91 tune and 93 gas and the car is running strong.

marcuskeeler

Switching octanes won't help on this as the ECU adjusts accordingly to that. So, if your timing is too advanced, that error will flow through the whole range of octane scenarios.
Bummer I know but you'll have to ditch the tune.