LSA G8 Idle Stumble

[wa04compg]

I have a 08 G8 with LSA Supercharger Ls7 cam and ls7 maf. Previous to the supercharger and maf change zero issues with drivability warm or cold. My issue is when it?s cold if you don?t let it warm up for 5 min the idle will surge up and down as soon as you give it gas and sometimes will actually die. When it is warmed up driving it around is no issue idles fine no surging coming on or off the throttle but if you turn it off for 5-10 mins restart it and give it gas surges again a few times but usually won?t die. I followed a idle tuning guide on here and it liked the stock idle timing and didn?t really need more air then the stock final air table. I have messed the proportional tables and have given it more and less timing spark control with nothing fixing it. Anybody have any ideas? I?m on my phone but I will attach tune tonight. Thank youG8 GT LSA Idle Tuning.hpt

[wa04compg]

Also forgot to say that ltft and ve lookup is turned off and my maf tuning has been via ngk wb

[wa04compg]

Added current tune! So I put all the stock G8 Adaptive Idle back to stock except for the Followers which I used from a stock 2010 CTS-V. With the stock Adaptives it is greatly improved from what it was. On warm start I do get some surging on my first stop sign but then after that it is fine. It did also surge once really bad when I put it into gear but again is so much better then it was. I will update if I am able to figure it out and of course if anybody has ideas for me would love to hear them thanx Toby

[lukearmstrong1990]

try setting your idle min VSS value to 550rpm so it has some margin from your targeted 600rpm idle.

halve your start up flare control spark reduction

copy your adaptive idle spark "coast" tables into the respective "gear" and "P/N" tables

copy your idle base spark table into the coast down table

set all proportional and integral idle airflow values to stock.

see how that goes to start.

[wa04compg]

Thanks for all the feedback! Last week I ended up using all the stock 2010 cts-v stuff that had to do with idle and also all the target rpm and startup airflow. My idle has been really stable during warm starts no surging when I put it in gear and give throttle and have been able to start it cold and drive it without issue. One thing I have noticed is on cold starts or if it has been sitting for a few hours if you give it small amounts of throttle or small blip in P/N it will undershoot target idle but once its fully warmed up it does not do this. I never have a need to give it throttle in P/N before its warmed up completely but just something I have noticed. For now I am pretty happy with it if anything changes I will report back

[Niemer]

Read this https://forum.hptuners.com/showthrea...e-tuning-guide

Pay particular attention to the bits about proportional and integral airflow. I had a very similar issue that turned out to be all the corrections working against each other to control idle and actually making it worse.

[crutt]

You still need to tune the vve table as it is referenced for transient fueling.

[Maxspeed96ct]

You still need to tune the vve table as it is referenced for transient fueling.

Even if the maf enable is set at 500 rpm?

[STAGEUP]

On G8s, you MUST tune both the VVE and MAF to get correct transitional fueling. No real way around it, unless you want to hack it and have a huge hump in your MAF curve. Also, make sure your "Enrich Desoot Mode" is set to disabled so that IPW isn't affected while transitioning into PE.

[Niemer]

What issues are you seeing with transient fueling if set to VE or MAF only? If running blended, yes, you'll need to tune both, but if one or the other I personally didn't experience any transient issues. Desoot mode is a different story, disable that for sure.

[Maxspeed96ct]

What issues are you seeing with transient fueling if set to VE or MAF only? If running blended, yes, you'll need to tune both, but if one or the other I personally didn't experience any transient issues. Desoot mode is a different story, disable that for sure.

could have something to do with your open loop vs closed loop fueling.

you could drop the closed loop enable to about 105* and see if that helps. But like others said, some basic changes to the VE may need to be made just for proper fueling before closed loop