Initial Startup Tune - Need some help to get it to idle please

[Goblue22]

Hi there,

Very new to HPTuners, but I have been studying a bunch online.

My new motor is not idling very well - I just need to get it to idle long enough to get it all the way warmed up, system check, one drive down the street, then get it on the trailer to the dyno and a professional tuner. Right now it idles for 5-10 seconds, then starts to hunt the idle rpm and swings up/down in increasing moves, can't correct, then stalls out.

I have added some idle spark advance, targeted idle airflow >20g/s, I do have appropriate injector data provided by FIC.

My current HPT file is attached. I do have a WB, but haven't got the math channel with Lambda error to work yet. Idling Lambda is in the 0.80-0.85 range which is low.

Thank you in advance!

Build:
Gen III PCM
4" Stroker LS3 - 416
Comp Cams 54-460-11 = .621/.624 235/243 113LSA
243 heads
Fast 92mm cathedral port intake
Silver LS2 TB
Lingenfelter conversion box.

[5FDP]

Lower the open loop EQ ratio. Lower the whole table some so it's not as rich and make everything past 120 degrees 1.00 so it commands stoich and not anything richer.

Do +/- 8 degrees on the over/underspeed spark correction. The 3 degrees you have usually doesn't work as well.

You may need to pull some fuel out of the VE table if it's still idling rich when commanding stoich.

Is the ETC area scalar right for that size throttle body, I don't know the exact number offhand to check.

[dhoagland]

Lower the open loop EQ ratio. Lower the whole table some so it's not as rich and make everything past 120 degrees 1.00 so it commands stoich and not anything richer.

Do +/- 8 degrees on the over/underspeed spark correction. The 3 degrees you have usually doesn't work as well.

You may need to pull some fuel out of the VE table if it's still idling rich when commanding stoich.

Is the ETC area scalar right for that size throttle body, I don't know the exact number offhand to check.

Isn't that Idle Air flow too high?
Also, shouldn't the main timing tables be bumped up a little to give room for the idle spark to work?

[Goblue22]

Lower the open loop EQ ratio. Lower the whole table some so it's not as rich and make everything past 120 degrees 1.00 so it commands stoich and not anything richer.

Do +/- 8 degrees on the over/underspeed spark correction. The 3 degrees you have usually doesn't work as well.

You may need to pull some fuel out of the VE table if it's still idling rich when commanding stoich.

Is the ETC area scalar right for that size throttle body, I don't know the exact number offhand to check.

Thank you for the suggestions 5FDP. I did get it to idle finally.

Changes I made along the way:

Set RPM Idle Proportional / Integral to 60 / 15 rpm respectively
Copied IAC Steps vs. Effective area and IAC Park position from another LS3 tune
Bumped relative idle spark advance region to 26 deg
Adjusted the over/underspeed spark correction as you suggested (this was the change that made it idle well) - I copied another tune and it isn't a flat rate, it ramps from 0 deg at 0 rpm to 15+/- deg at 150+/- rpm
Iterated several times on the VE table in the idle area with the WB

I will look at the Open Loop EQ table - also consult with the tuner when I get it to the dyno
I need to check the ETC Scaler - the other tune had a different value (mine is currently 0.030, other guy is 0.0255)

Thank you so much!!! Last log file and the tune file are attached. 7Working copy 03-13-2021.hpt09-13March.hpl