Lean tip in

[151LE]

I have been battling this lean tip in issue from the start of tuning.. I have a Ls3 to LSa conversion running 6 lbs of boost. Stock cam and such. The car only has a lean tip in in open loop while cold and open.loop hot start. I have tried adjusting just about every setting via transients timing tables it will spike to around 1.03-108 lambda which will produce spark knock. This is only in first gear take off. The car is a manual.

Once the car is in c.l. operating temperature the lean tip in issue goes away. However in c.l. mode at 95 degrees, motor still cold, it has the lean tip still until operating temp has been reached.. any suggestions would be appreciated.

[Lakegoat]

Sounds like you need to fatten up a few cells that you have identified as lean. Have you done that to your ve tables? Are you in SD? Where is your tune and a scan of the event? What kind of car?
I guess it must be a 15 Camaro from your name?
Is this a DI motor or regular injectors. If it is regular, then you have to change the injector data that came with the LSA kit.

[151LE]

cold take off maf only.hpl at around 3 min 9 sec on take off you can see the afr gauge reading 1.20 lambda. No spark knock on this scan.Don't look into the fuel trims, it was just reflashed. To answer your question yes the injector fuel data is interred correct. triple checked that. I've even played around with fuel/general/injection boundry with no effect. also o.L. gas gear has had no effect either.

[151LE]

yes the car is a 2015 camaro which is not direct fuel injected. I am running maf only at the moment, ive tried to run s.d. only and yes I had the v.v.e dialed in, ive ran the p.cm stock for both the v.v.e. and maf and it doesn't seem to help this lean tip in.

[lukearmstrong1990]

tune?

[151LE]

e-85 and gas new tune 2019 aug.hpt here is the attached tune. feel free to rip it apart. it is still a work in progress.

[151LE]

On the scan above there isn't much knock happening here, however on must occasions it will knock up to 3 degrees in light throttle take off.

[07GTS]

if u look on your vve there is a dip around the same rpm/map area, if u have it set to show 1 bar u can see it, its not as bad in the 2 bar layout but id suspect its still there, u could even change around the zones to get more even coverage encase going thru small zones is throwing it out in the background, thats just a guess tho as i dont do much vve stuff nothing alse looks to stand out

[Lakegoat]

Look at you maf curve in 2d. There is a big blip. Smooth it out.

[151LE]

Are u referring to around 5200 Hertz? Or are u meaning in the lower Hertz area?

[151LE]

I'm running m.a.f only so the v.v.e. shouldn't be a factor..

[151LE]

tune?

Did you get a chance to look at the tune?? Anything stand out to you?

[07GTS]

I'm running m.a.f only so the v.v.e. shouldn't be a factor..

zero out your VVE to see if its still being used ? maf is too slow for all fueling where map is instant it needs to be used for best results

[151LE]

I have noticed that while running m.a.f. only it does seem a little doggy or slower while in the the lower r.p.m.'s I was running m.a.f only to see if I could correct the lean take off.

This is the part that had me stumped though, while in open loop or cold c.l. it has a lean stumble or on hot restarts before entering into c.l., but once the motor is up to operating temp, the lean spike is completely gone. Any ideas as to why?

[IARLLC]

You really need the VVE right on in order to make accurate transitions. The MAP finds out that you opened the door (throttle) WAY sooner than the MAF. And a colder motor is much more likely to complain about a lean moment.

If you get your VVE and MAF really dialed in and it still happens, your open loop maps and even cold closed loop temperature related modifiers might take you leaner than desired. Fuel>Open Loop>Open Loop tables and Open Loop Gain tables might help with this. Fuel>Transient>Warm Up Transient Fuel Correction>Stomp Compensation Base Gain might be a little off for your exact combination. I wonder if you Spark>Advance>Catalyst heating>Engine Run Time and Engine Coolant Temp might retard enough to cause dippy behavior too....

But I would focus on getting your airflow models (VVE and MAF) really right FIRST and then see if any other improvements are even needed.

[151LE]

Thanks for the reply, I will look into that.