Quick Sh0t xMLx

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.

Russ K

iTrader: (1)

To fix the low spark timing off the line, zero the Burst Knock Retard vs Rpm table. What is the WOT AFR? Also what temp is the coolant at?

Russ Kemp

Quick Sh0t xMLx

I was looking at that chart but I wasn't sure what it did. I have no idea what just happened but when I open the log files they're all blank. Coolant was anywhere from 170-210 at the highest, I keep a close eye on that.

I have no wideband so no clue what the AFR is.

MontecarloDrag

iTrader: (3)

You need a wideband. There is no point messing with fuel at the track if you have no feedback from a wideband.
The car is auto or manual?
A little more info would help

Upload the logs

jimmyblue

iTrader: (11)

Some traction control schemes will pull spark. Was yours
off?

Quick Sh0t xMLx

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.

MontecarloDrag

iTrader: (3)

I have seen some trucks with 2 to 4 degrees of KR, 100% stock, not a single mod, 92 octane fuel

Quick Sh0t xMLx

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.

jimmyblue

iTrader: (11)

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).

Quick Sh0t xMLx

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?