VE tuning Hunting/Surging Idle

[Burntendzz]

Currently working my way through this tune. I've made some good headway with the MAF tuning. Today I decided to try getting the VE dialed in. When tuning the VE I get large swings in RPM @ idle and the car dies within a few seconds. Driving seems to be fine, for the most part. My first thought was adjusting Adaptive Spark Control, the car wouldn't die any more but the idle would still swing back and forth just much higher. With "MAF only" car idles and drives fine, besides a small surge coming to a stop, which it has always had with this tune.

[Burntendzz]

Here is another log attached. You can really see the oscillating of RPM in this one.

[kevin87turbot]

Give this a try. It should help out. What injectors are you running?
SamTune_injectorschange_step15VEenabledkwmod.hpt

[Burntendzz]

Give this a try. It should help out. What injectors are you running?
SamTune_injectorschange_step15VEenabledkwmod.hpt

Thanks Kevin! They are FID 1300cc injectors. I'm assuming the Idle Advance Coastdown might have been the culprit? I'll give the tune a shot this afternoon.

[blindsquirrel]

Your PE settings were letting it get into a sort of feedback loop, or at least making normal idle adjustments create the surge. MAP enable was... 35kPa? (from memory, looked but already deleted) and throttle 10%. At least that's what my wild guess would be. Anyway, it couldn't have been helping. In your log, with every surge it goes from CL to OL Accel.

[kevin87turbot]

Your PE settings were letting it get into a sort of feedback loop, or at least making normal idle adjustments create the surge. MAP enable was... 35kPa? (from memory, looked but already deleted) and throttle 10%. At least that's what my wild guess would be. Anyway, it couldn't have been helping. In your log, with every surge it goes from CL to OL Accel.

That's exactly right.