[Cougar5.O]

I get remote tuning from Decipha. I seem to be constantly bugging for improvements to my tune and he gets a gold medal for putting up with my nagging.
I’d like to get a bit of a handle on tuning without taking up Decipha’s time so I only bug him on more urgent needs.
Before I can start playing with tunes, I need to understand exactly what it is I’m seeing on the logs. What certain things mean, what readings are optimum, things that look odd etc.

ie, here is a screenshot of a recent log. Car fully warmed up and driving. The LAMBSE are pretty close to 1.0, which is stoich, correct? Is that number a result of a table, or does it change based on info from the HEGO’s ? I am under the (possibly incorrect) impression that hego’s help the KAMRF’s make the fuel correction.
That being the case, what would cause the fuel to be out so far that the KAMRF’s read in the .700’s. If fuel is correct wouldn’t kamrf’s only stray marginally from 1.0? View attachment 1075650

You are correct - the short-term trims (LAMBSE) are fine - and yes they react to the HEGOs for each bank. Your long-term fuel trims (KAMRF) are off more than you'd expect with a properly dialed in tune/MAF. There's a lot not apparent on a screenshot (steady-state?) I'll need to refresh my memory a bit as it's been a while since I tuned this strategy. It would be better if I could look at the entire datalog.

 

[Cougar5.O]

KAMRFx and LAMBSEx are multipliers. As shown below, KAMRF >1 adds fuel and a LAMBSE >1 is multiplied against 14.64 which commands an AFR > 14.64, thus removing fuel.

AM = Air Mass as measured by the MAF.

It's a little confusing, but looking at the equation and following the rules about division will help remind you what's going on. Still not enough information to determine what your issue is. The implication looking at the two screen shots is that you're rich under this particular condition. This is why looking at the entire datalog would be helpful to see where the trigger is for your issue. A little rich shouldn't cause major problems.