E38 commanding lambda 1.02-1.05 open loop??

[bjl1990]

Open loop tables for gas and alcohol are all set to .95 I cant figure out why my commanded lambda is ranging from 1.02 to 1.05 the longer it runs the leaner it commands! Wb reading starts at .96 and slowly leans out to match the commanded 1.02 to 1.05

And yes it is running in OL while I?m having this issue

When Its in closed loop its fine with a commanded lambda of 1 and WB reading of .99-1.0

completely stock L76 other than a mafless otr I have the 2bar map os patch applied although it makes no difference it still dose the same thing with or without the patch

I have a vcm13 cam and full 3inc exhaust with extractors and ported Ls3 heads to go on over Christmas

Current tune is chopped up trying to fix the issue so no point posting that just hopping some one has had a similar issue

[Ben Charles]

Change it from .95 to 1.0

[bjl1990]

It was originally set to 1.0 and it was still commanding 1.02-1.05 or leaner I set it to .95 to try to get it safe enough to continue with tuning the volumetric efficiency

[07GTS]

IVT gain gas table also needs to be 1.0 in the operating temp range for it to command 1.0 the OL tables will always go to the richest value

[GHuggins]

You might want to post the tune and a log. Then you do know that a GM calibration uses multipliers for fuel and not "lambda" settings per say too right? SO anything less than a "1" setting with pull fuel and anything over will add or command "richer"

[bjl1990]

I knew the PE table was a multiplier and obviously all the multiplier tables I wasn?t aware that the OL tables were that could be where I?m going wrong.

This is my first gm tune I have mainly done Barra tunes

I don?t have my laptop with we right now I?ll post a tune and log tomorrow who knows where else I?ve gone wrong

[GHuggins]

It's OK. Just a learning curve going from vehicle make to vehicle make. The descriptions at the bottom will sometimes help out with figuring that kind of stuff out. Pretty much everything other than PE is a multiplier in GM. Ford uses lambda and multiplers and then dodge uses lambda, weird dividers and multipliers.

[bjl1990]

ok i got a couple of logs this morning and if attached the sh#t show of a tune file go easy on me fellas


this shit.hplthis shit idle.hplmafless 2bar lets try this shit step2.hpt

[GHuggins]

Just glanced at the tune and this may seem like a stupid question, but why not set all of the fueling tables to stock, put back into closed loop and tune it the way it's going to be in the "real world"? Use fuel trims vs wideband to get O2's close if even need be, then use fuel trims to dial in closed loop or even detuned PE and then finally widebands for final PE... This also helps to show open loop fueling issues while tuning for cold starts... Just don't see a point in making things extra hard on yourself

[bjl1990]

Thanks for the advice GHuggins I?ll give this ago tonight. This I how I was tuning it then I finally put my WB in so I changed to open loop expecting it to be easier and more accurate