Odd after tune issue

[Spindoctor]

I delivered a 2004 Z06 with vortec and tune to an out of town customer.
Everything runs strong with 440s at the wheels.
However the customer states that when he hits a long hard pull then shifts he gets a
traction control warning in the display and the car goes into limp home mode. This happens in or out of tracs mode, and he is sure the tires are not spinning.
If he pops it in N and shuts off the car then restarts it all is good.
Before I have to drive a couple of hours out of town on a possible warranty issue I wanted to know if this was common enough to have a known fix.

Thanks in advance- Tim H

[ScarabEpic22]

Hmmm, I know some later Vette and TBSS guys have been fighting with StabiliTrak and Traction Control kicking in at inopportune times. Not sure Ive heard a fix yet, have you made sure the ETC limits are raised well above factory? They're in the Engine Diagnostics section of the tune, not the actual Engine section.

[swingtan]

Post the tune..... At a guess, it's the air flow sanity check.

[Spindoctor]

Here it is-JohnsonR04Vette_0014.tun
Now that I am looking at the ETC max predicted I can see where it is falling off hard past 5500rpm.
My last dyno log shows 1.08 grams per cyl at 6k rpm well above the .825 on the expected graph.
I would think adding about 10% across the ECT graph above what I logged should take care of It.
Any thing else you see that I missed?

[SOMhaveit]

It's C6101. I'm not boosted but mine is 1.4 X the oem parameters.

[Spindoctor]

So a 40% (*1.40) increase across the boosted end of C6101 & C6102 should keep me out of limp mode?
If I go too high is there another set of limp mode faults I could run into?

[swingtan]

What you would do is to take a log and see what sort of air flow you get under peak loads at different TPS % and RPM. It's a little like tuning the VE table in that you want to see what is the expected airflow for the set conditions. Then allow an amount of error above these values and put those figures in C6101. If you wanted to guess, I'd be selecting all cells above 0RPM and adding 50% for starters, maybe 60% depending on how much boost you are running. Then fine tuning it from there.

If you know the VE table is accurate, you could try calculating the airflow from that. You would still need to guesstimate the throttle % though.

Simon.

[ScarabEpic22]

Ill check the tune out tonight, but pretty sure that's going to be the problem. ETC at stock values + boost = PCM/ECM doesnt like it and goes into limp home mode.

Simon is dead on (as usual), start with a 50-60% increase and move up or down from there. If you still get limp mode, note the g/cyl and up it a little.

[Spindoctor]

I will probably go out to the vehicle this week end and re tune those areas.
Upon checking my history on the last supercharged vette that came in, found the base tune had already had those changes made.
I just didn't think to look at it this time as on the dyno it did not produce the limp mode.
As usual life on the street is not the same as life on the dyno.