I am having this problem on both of my brother's trucks, one an 02 Denali and the other an 04 Z71 Tahoe. I have all the torque management removed(I think) and from a dead stop and nail it and it will pull timing down around 0 initially. It doesn't pull any at shift. Is there something i'm missing with Tq mngmt or how can I tune this out? Using HPT.

 

Send me a copy of your .bin I'll take a look. joshluther@myeastern.com

 

email sent.

 

make sure you have removed both engine and transmission torque managment, and go ahead and disable transmission abuse mode (if it makes you uncomfortable, just do it for the testing purposes and put it back)

 

I think I did all that but i'll look again.

 

That sounds like abuse mode kicking in.

 

It could be burst knock timing pull. When the PCM sees a rapid gain in air flow, it thinks it could knock and pulls a bunch of timing in anticipation of knock, even though non has occurred. I'd check that, if you haven't already

 

I've read a few posts by Mr Bubb (w4m) saying there is a launch spark modifier table in the PCM that none of the three tuning packages have as an option to edit. If that is true, it would most likely be your culprit.

That or burst knock like kbracing said. Check your delta air mass tables.

 

If thats so, I would like to know what kind of tuner he's using to see this? AFAIK, he is using EFI Live to tune.

Also, if there is this table why doesn't everyone get timing pulled at WOT?

 

Those were two questions that immediately popped into my head when I first read his post about it. I know that I don't have this launch issue.

Personally, I'd put money on it being a delta air mass issue, or timing being pulled due to MAF and MAP readings being too far apart with such an influx in air...

I just posted what Jesse has claimed to exist to further discussion on the topic.