I guess this may be where the bigger injectors come in?? Maybe not, could be over boosting too? After bombing around by myself for a while my neighbor came home and we went for a little test mission. Went out down some country roads far away from people and laid into it. We warmed it up with a few partial throttle runs up to 90mph or so, and I know the computer is still learning and all but we did a run from 50mph all the way up to about 125mph, my caddy gauge was past the 120mph mark so I'm guesstimating here. All was well at this point and the truck was warm, I did get some reading over 900mv from the O2 sensors but who knows there. After this we pulled out on to another long straight road and nailed it, it was good up to abut 4800rpm the stumbled real hard so I backed out slowly and rolled into it again a few seconds later and the same thing happened. It felt like it was not getting enough gas or the ignition was cutting out or something. Any of you other turbo guys see this with your set-ups? Forgive me if I am ignorant here, I'm still learning.

 

Do you have a boost guage on there? Honestly it sounds like too much timing, or not enough fuel.

 

No boost gauge yet, I will be ordering one soon when I find a good brand and one that mounts where I want it.

 

Sounds to me like you ran out of fuel. You may want to take it easy intill you get that thing hooked up to hptuners or atleast some kind of scan tool to get some readings but good luck.

 

Agreed, go easy until the tuning and/or larger injectors are installed. Else get a wideband reading to check A/F ratio.
Have fun, but not too much fun, til the tuning is done.

 

I will heed your warnings oh master of the LS1s, I think I just got alittle too crazy a little too soon. So can I get anyusefull information from Predator diagnostic live data screen? It seems like my O2 readings are ok, I did see some numbers above 900mv yesterday but not too high. What should I be running about? Also what king of MAP readings should I be getting as well as MAF? This learning curve will be a little frustrating but worth it.

 

screw you MV predator thing get a wideband and did you hear any know at all or did it just drag nuts???

 

One thing to note, the computer learns some idle parameters, and all part-throttle positions... but when you go WOT, there is (nearly) no learning involved - the computer goes open-loop, and runs off of hard-coded parameters.

I say "nearly" no learning, because if your long term fuel trims are positive, they will be added to your PE table fueling (performance enrichment table - which is the main fueling table at WOT).

 

Without knowing how much boost you were running, this is all shooting in the dark, but a couple of things come to mind:

1) severe knock / detonation -- it was never audible in my truck, but I've seen 10* of KR at those RPMs with the same symptoms (on a very hot day...)
2) running out of fuel (which can / will lead to #1) - assuming you have stock injectors and a stock fuel pump, you can't go much more than 5psi
3) too much timing (which will lead to #1)

Basically, your turbo didn't stumble, your motor did. As Marc said there is very little "learning" in the stock PCM -- driving 50 miles ussually = max learn, and none of it would affect WOT @ 4800rpm.

If it were me, I'd verify your AFR on a wideband as suggested, get a better tuning solution, and a boost gauge before going to WOT again. The consqeunces of going under boost with a faulty tune / fuel system are catastrophic. Be careful

 

Say again brotha!!!!

You don't know how much boost you are at. That spring can vary. Iv'e seen some guys say they were boosting 7psi right off the bat because of the spring their wastegate came with. Be very careful man. I'd hate to see your next post be about a blown motor.

The guys covered most of the stuff I would have said. Also, you did change your plugs and regapped em at .035 right?