Help, 0 degrees advance off the line
Thread Starter
TECH Apprentice
Joined: May 2008
Posts: 351
Likes: 0
From: Charlotte,NC
Help, 0 degrees advance off the line Hey guys I went to the track today and to sum it up the car ran like ****. At WOT off the line it shot down to 0 degrees advance timing and went back up to "almost normal." Obviously this caused my 60's to be abysmal, on top of that KR was anywhere from 2-3.5 degrees. The car has never done this before and I haven't changed anything from the last time I scanned it(last week).
I have absolutely no idea what's going on. First one is my tune, the other the last log I got(no spray, they all looked about the same). I'm still at the track and LS1tech won't let me upload the tune, I'll try to do it when I get home. If any "pros" want to help I can probably send it via email right now.
I have absolutely no idea what's going on. First one is my tune, the other the last log I got(no spray, they all looked about the same). I'm still at the track and LS1tech won't let me upload the tune, I'll try to do it when I get home. If any "pros" want to help I can probably send it via email right now.
Thread Starter
TECH Apprentice
Joined: May 2008
Posts: 351
Likes: 0
From: Charlotte,NC
I have no wideband so no clue what the AFR is.
Thread Starter
TECH Apprentice
Joined: May 2008
Posts: 351
Likes: 0
From: Charlotte,NC
It was off, the car is an auto. I haven't messed with the fuel at all since there really is no need. Just wondering why would a stock car pull 3.5 degrees of KR? I'll try that burst retard thing, after searching more seems to be a fairly common occurrence.
I have seen some trucks with 2 to 4 degrees of KR, 100% stock, not a single mod, 92 octane fuel
Trending Topics
Thread Starter
TECH Apprentice
Joined: May 2008
Posts: 351
Likes: 0
From: Charlotte,NC
Update: Turned burst knock retard off, turned timing via TCS pulled off and it's still doing the same thing. I finally got a log(timing set at 28 for NA runs). First is tune, second is log.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
Five Reasons the Camaro Was the Most Pivotal Player in the Pony Car Wars 2.0
Brett Foote I looked at these and can see no reason for the timing
drop.
However I have seen spurious data drops in logging
before, and seemingly related to "brain activity". I
did not look at whether other sensor values were
squirreled out in that frame.
I recommend if you think it's real, to log every timing
PID you can get (advance and retard). If it's dropping
to 0 for reals, then either there's a huge and exactly
right retard being laid down, or your main timing
advance PID would show a zero momentarily. There
is nothing in your timing tables to do that.
I do notice that your dynamic cylinder air mass value
seems insanely low (0.6x; 0.8x is more normal for a
5.7).
drop.
However I have seen spurious data drops in logging
before, and seemingly related to "brain activity". I
did not look at whether other sensor values were
squirreled out in that frame.
I recommend if you think it's real, to log every timing
PID you can get (advance and retard). If it's dropping
to 0 for reals, then either there's a huge and exactly
right retard being laid down, or your main timing
advance PID would show a zero momentarily. There
is nothing in your timing tables to do that.
I do notice that your dynamic cylinder air mass value
seems insanely low (0.6x; 0.8x is more normal for a
5.7).
Thread Starter
TECH Apprentice
Joined: May 2008
Posts: 351
Likes: 0
From: Charlotte,NC
Do you think it's somehow dipping into the low octane table instead? I ask because I looked on the histogram and right when the fall in timing starts it's at 800 RPM and 0.52 dynamic cylinder. In the low octane chart that's 1 degree of advance. Also I had advance set at 28 in the high octane, 22 on the low octane. Coolant temp didn't remove or add any and IAT removed 2 degrees but advance was at 21.5(again closer to low octane value).
You think this could be the problem? Should I just copy the high octane chart to the low octane one anyway? What would cause a car to dip into the low octane(it's got fresh 93).
Edit: After a little googling it seems like if any KR is detected it'll use some numerical calculation to arrive at a combination of low/high octane tables. They also said it takes quite a while for the PCM to go back to strictly the high octane table. I was getting a bit of KR over the last few days. I'm thinking about copying the low/high tables, any objections to that?
You think this could be the problem? Should I just copy the high octane chart to the low octane one anyway? What would cause a car to dip into the low octane(it's got fresh 93).
Edit: After a little googling it seems like if any KR is detected it'll use some numerical calculation to arrive at a combination of low/high octane tables. They also said it takes quite a while for the PCM to go back to strictly the high octane table. I was getting a bit of KR over the last few days. I'm thinking about copying the low/high tables, any objections to that?
Last edited by Quick Sh0t xMLx; Mar 4, 2011 at 03:10 PM.
