LS6 w/ LS2 TB - Dies when coming off the throttle

[jclayc]

Hi everyone,

I'm very much a noob at understanding tuning but I've been doing a good bit of reading in the forum & thought I'd post a question.

The car: 2005 CTS-V, M6, 346ci LS6 w/ TFS 220 heads, Comp Cam 229/239 .627"/.621" 111.5+3, 63lb injectors, Fast 92, LS2 90mm TB, LS7 clutch and 19lb lightened flywheel. After a tune, aside from producing somewhat disappointing dyno numbers (390hp/383tq), the issue is that the car idles and runs fine but, when coming off the throttle, the engine dips down to around 260-300RPM and sometime dies (?particularly if I'm turning the wheel sharply?). If it doesn't die, it'll dip and rev, dip and rev like 5 times and eventually find idle around 950RPM.

I've seen a few similar posts about this that all say the ETC Area Scalar needing to be 0.0192 instead of the stock setting of 0.0255. I believe IAC reset is irrelevant since my LS2 TB is electronic. I believe the culprit is the light flywheel, requiring the Throttle Follower Decay be adjusted ?DOWN?. Is that correct? Does anyone see anything in the attached hpt file that I should ask my tuner about?

2005CTS-V_LS2TB.hpt

[camj256]

I hate to bring back such an old thread but I'm having the EXACT same issue. Just got a basic tune on the MAF and I changed the ETC Area Scalar but i'm seeing the exact same issue. Car dies coming off throttle. If i force i come off throttle VERY VERY slowly I can get it to stay idling like normal.

2005 CTS-V M6
AFR 220 heads
224/230 cam
ls2 throttle body (swapped from the smaller ls6 TB)
ported fast 102
stock clutch/flywheel/injectors.

I'll get a log file as soon as I can tomorrow. In the mean time are there some tables I should look at for this?

[mowton]

Make sure MAF/VE is tuned correct for the idle area's and BRAF is close...idles at desired rpm and timimg is hovering around your commanded. If timing is biased low, reduce mia, if high then increase mia. Adjust the Throttle follower decay values to "soften" the return to idle. Like a letter "J"...come down to a point, then slow down the return to allow a soft landing at your commanded rpm.

Post tune and log

Ed M

[camj256]

Hey, thanks. I accidentally made another thread about this before I saw you're reply. I'll give what you suggested a try in the morning. My tune/log are in my other post: http://www.hptuners.com/forum/showth...g-off-throttle

What is mia?
"If timing is biased low, reduce mia, if high then increase mia."

[mowton]

Sorry, its minimum idle air which in your year/PCM/operating system is actually call Base Running Air Flow or BRAF

Ed M