LS3 - adaptive idle / flare up issue + a few others

[rob_mac]

hey guys

have a few strange issues on this one, and was hoping could get a few tips

1. im guessing this has something to do with adaptive idle routines as it happens as i drop below the max VSS of 3.0km / hr in adaptive idle settings

vehicle idles great at commanded rpm of 850... but when i am coming to a stop, the vehicle rpm will drop down to normal idle rpm.. once the vehicle stops, it flares back up to about 1050 - 1100 for a few seconds, then it slowly brings it back down to commanded.

is this an adaptive idle setting, idle airflow setting, idle timing ??? havent had one do this to me before

2. after a long-ish drive (30 mins or more), the idle gets unstable and begins to hunt.. however, when sitting and tuning the idle is nice and exactly where commanded... anything pop out that may cause this?

i havent tried anything yet to attempt a fix at this - i was thinking possibly some table to do with ECT


3. when tuning wot, vehicle seems to have a weird lean hump at around 3500 rpm (graph attached)... however the hump is not present in the ve map ... cant seem to work out why she is there?

any suggestions from any gurus

thanks in advance

fwiw

vehicle is 09 ls3 m6

231/247 lsa 113 camshaft
vcm otr
dual 3" exhaust
TB has been ported - approx 5.5 - 6mm hole

tune file + wot dyno ramp attached

[DSteck]

I'll check out the tune later. Are you actually working on the VE coefficients or just tuning the MAF?

[rob_mac]

2 bar mafless os applied

[DSteck]

Can you post the stock file? Your final idle airflow table looks kind of goofy, and has a TON of airflow for 1st gear and reverse, but seemingly stock for the other lines.

Also, your adaptive spark for idle is totally screwed up. Set those tables back to stock. Plus, with M6 Spark Smoothing enabled, you don't need to drop timing down to the same as idle in the low rpm, low load areas for high octane main spark.

One last thing... if it was me, I'd change the axis labels on the VE table to only go up to one bar so you have more resolution.

[rob_mac]

tried to bump the airflow figures up a bit in first and reverse to help with sometimes wanting to drop / stall on light clutch riding etc etc (aka reverse park maneuver etc)

is there another table to play with to help correct this behaviour in e38 ala throttle cracker in gen III ?

will drop all airflow figures back to stock + maybe only bump 1 -2 g/sex

will change adaptive idle over and underspeed tables back to stock

and tiing in high and low octane spark maps in the 0 - 1500 range back to stock and see what happens

[rob_mac]

following changes made:

changed the adaptive idle over / under settings back to factory
changed base spark timing to 15
low load rpm point in HO spark table back to factory

and problem of it flaring back up once you come back to a complete stop is completely gone

im hoping this will possibly address the sometimes hunting after a longish drive - but have to go on a longish drive first to find out

thanks a million !!


any ideas on why my afr curve has that slight lean hump in her at 3500 rpm ?????

[DSteck]

Not sure on the lean bump. I'd be curious to see your VE table after changing the axis labels to one bar.