Xtremespeed

iTrader: (25)

I enriched my pe table about a month ago to solve a lean detonation problem. I got a baseline dyno on the car at G force about a week and a half ago, and Mike said he could tell I had a fueling issue. We assumed it was too rich, because I had changed the pe table.

I ran the car pretty hard Friday night, and noticed some detonation again. So I decided to make a log run, so I could adjust my timing. Mike said I should be able to run 28*. The 02's are very rich. .940-.950 average, which would be explained by the pe table being off. I was going to tune this today. I showed no more than 24.5* and up to about 4* knock retard. It was hot as hell outside. 103* I think. Ect was 221-225, and iat was 117-124. Can I just not run the car when it's hot outside?

I have a 160* thermostat, with appropriate fan settings, and I just installed an Ls6 intake, so I know the top end is clean. Other than being hot outside, what should I be looking at? Why the detonation and knock retard with only 24* timing, and soo rich? Seems the over rich condition and low timing would keep it from detonating.

oange ss

iTrader: (50)

I'd try a Seafoam treatment

V8_DSM_V8again

Yes the heat will effect the amount of timing you can run.

The intake air temperature affects that alot..

Xtremespeed

iTrader: (25)

Sea foam is not going to help. I just had the intake off, and I know the top end is clean.

I understand the basics, just wondering if there is something else I should be looking at. Seems even with it being hot outside, I should be able to get the car to run without detonation.

V8_DSM_V8again

I'd try a different o2 sensor(s) if you can too... Unless they are new too..

Xtremespeed

iTrader: (25)

What would lead you to beleive they are bad?

V8_DSM_V8again

Its one possibility.. You base your tune off of them... I have seen it before a false 02 reading by a goofy sensor...

Honestly get a LC-1 wideband and datalog using innovatives logworks software and retune using the wideband...

I think you will find a big improvement

Xtremespeed

iTrader: (25)

I made another log tonight. 78* outside. O2's about the same, but no detonation, no kr, and up to 27.5* timing. Ect was 181-185 and iat was 88-97. I guess you just can't race these damn things in the summer. I sure would like to know what everyone is doing at the track to keep from pinging!

Xtremespeed

iTrader: (25)

I also noticed that my ltft's did not go to 0 like usual. They were at 4.7 almost all the way through. What would cause that?

V8_DSM_V8again

HIGHER OCTANE

See about a better CAI system...

V8_DSM_V8again

Its a little lean or the O2 sensor(s) are reading wrong..

It will go back to 0 under the exact same atmospheric conditions it was tuned under using the exact same fuel. That little variance is'nt alarming..

Tune on race gas once then idle on 93 oxygenated and look at the trim!

Other things like fuel filter clogs, FPR getting weak, and weakening fuel pumps can do it to.. I'm not looking at the car but know what systems I would check for problems..

Just because you have the correct base pressure at idle does'nt mean the pump can keep it across all RPMs and engine loads.. At higher rpms with a larger load brings on the max fuel requirement. A weak pump or a partially blocked filter will cause problems there.

Since the fuel trims are only idle and cruise those may not be showing the whole problem... Buy or borrow a wide band and check it out...

zrater

mine too, i have a 02 stripper and heat soak kills this thing . i change timing
a little and the ve tables and kept things cool and the ping was almost gone, accept
about 4000 still get a quick rap at about 4 kr. intake temp seems to be
the big factor.

V8_DSM_V8again

Consider this

http://www.designengineering.com/pro...sp&pid=4&tid=1

Xtremespeed

iTrader: (25)

Doesn't seem like all this would be necessary with a stock car. I can understand when the temps outside are 100+, but damn.

I recently replaced the fuel filter, so I know it's ok. I need to try a wideband.

Everyone recommends raising the timing to 28*, but I can't even keep it from detonating with stock timing, unless I add fuel to the pe table, and it's less than 80* outside.

V8_DSM_V8again

what kind of fuel are you running on?

Try a fuel change.. Different station or brand..

Xtremespeed

iTrader: (25)

Shell 93

jyeager

There are a lot of things that you should check and double check as the previous posts have indicated, but I want to point out that you ignored the seafoam statement pretty much out of hand. If you had the intake off and know it's clean then the seafoam treatment isn't necessary, but the point there was that you may have oil contamination. You might not, but since we don't know your car we've got to play the odds. I think that statistically speaking, most unexplained detonation problems on our cars are due to oil contamination through the PCV valve.
You should try one pull with the PCV system disconnected to make sure. Or, if you consume zero oil between oil changes you can pretty much rule this one out. If you do consume any oil at all, the seafoam would still be a good idea for a few reasons: 1) it's cheap. 2) it's easy 3) you could still have carbon buildup inside the chambers even if you can't see it through the intake ports.
Good luck solving this.

V8_DSM_V8again

mopar cobustion chamber cleaner..

Xtremespeed

iTrader: (25)

I don't understand what you mean by out of hand. I stated in my first post that I had just installed an ls6 intake, and the top end was clean. I mentioned that because I knew people would suggest seafoam. I was just trying to convey what all possibilities I had already eliminated. I wasn't unappreciative of the thought, just confirming that possibility had already been considered and checked. Please correct me if I am misunderstanding. I appreciate all the help and suggestions.

jyeager

Sorry if I offended, probably a bad choice of words (negative connotation and all). Typically if an engine is all gummed up you'll see carbon deposits on the back of the intake valve and you didn't see that. But I wonder if the inside couldn't still have carbon buildup?
If you are aware of the oil issue, and have considered it the most likely culprit, yet ruled it out then you're covered.
I hope you figure it out.