GTO stalling at stops

[Fox95]

I have a 2006 GTO i am working on and it has a real lumpy cam in it and when coming to a stop at stop signs or redlights the idle would dip well below 500 rpms and sometimes would stall.

here's what i did to correct the problem and so far it appears to be the cure:

under---- Idle>Idle RPM>Adaptive Idle Proportional>Airflow: add 4 to every row and column(transition and coastdown)that's on the positive side (32 rpms - 512)

under---- Idle>Idle RPM>Integral>Airflow: multiply every row and column(transistion and coastdown) by 2 that's on the positive side (32 rpms - 512)

do not mess with any numbers on the negative side as this seem to negate the changes on the positive side.

ben

[redhardsupra]

do you know what this does/how it works? could you post a scan of your idle before and after these changes?

[Fox95]

well my theory goes along with the description of what it does in the software.

when the vcm sees too high and idle rpm then it subtracts the value that's on the negative side of the table from the rpm it's seeing.

and vice versa, when the vcm sees too low and idle rpm then it adds or multiplys by the numbers that are on the positive side of the tables.

so as you are transitioning to idle at a stop and the idle drops below the commanded idle rpm then the vcm will use the positive numbers to get it there at a faster rate.

This is only speculation at this point, and like i said from what i have observed so far it seems to be the case.

I will do some data logs if i can, I have to give the car back to the customer today and I don't have much time to experiment as I spent mucho time already just trying to get it to not die coming to a stop.

[EC_Tune]

What is your MAF airflow compared to your Base Running Airflow table? If those two don't match pretty well, you will have idle issues.