My commanded AFR is changing rich on me!

[joecar]

Make sure that the units agree between the pids in these places:
- scantool Data tab (edit these on PIDs tab by rightclick->Metric/Imperial);
- tunetool table axis (edit these by going Edit->Configure Display Units);

Check also this:
In tunetool, go Edit->Properties->Display and check that fuel units are not Lambda.

I like to use these units: VE units g*K/kPa and fuel units EQ.

[Chris81]

Ok, looks like I found the problem! I will do some more logging soon to make sure, but it looks like it ended up being the COTP after all.. I guess it does alter the commanded AFR.

I'll include some logs to show.. I went ahead and adjusted my fueling to get rid of the positive trims, so now my avg's are .4 and -1.4 on the last log and 0 at WOT

The only thing I did between logs is turn off B0701, the first log shows it going rich again, as always.. and the 2nd log it doesn't do it at all.. I did get a bit of KR though, so it looks like I might need to add a little fuel. I wasn't around the shop so the WB wasn't in, but I promise its right.

Thanks for everyone's help!

Chris

PS, the files included are the 2 logs and the current tun. file in the car.

[WeathermanShawn]

Wow, good job!

Kinda going fast there..Just kidding. You ought to see some of my logs. We have some pretty wide open roads here. I always count my 1 second frame(s) Vss acceleration to compute 'road HP'. Saw you are doing two-second frames, so nice to compare.

Noticed you maxed out at 90 Kpa. Are you at elevation? I can barely hit 82-84 Kpa on a good day up here at 'mile high'.

You may have discovered something worthwhile here. It appears when you hit about your 3rd WOT in succession, your COTP kicks in. Never realized it actually changes your commanded fuel. Perhaps there is a 'timer' involved that calculates how many seconds your narrowband O2's stay above 800mv. You seemed to have hit it.

I have ran headers/w cats for over a year now with COTP disabled. Always noticed before disabling COTP I would hit ~11.7 on the wideband, but never logged commanded AFR at the same time.

[joecar]

Chris,

That's a good log... see how EQIVRATIO follows the PE table (which is richer than the OL commanded fuel table at those points)...

As WeathermanShawn said, note that you're logging at 5 frames/second since your pid channel count is above 24.

[Chris81]

Thanks guys..

Weatherman.. i'm out in west Texas where it is around 3000 ft actual elevation.. and there are PLENTY of open roads..haha. I have noticed that the car would usually start to go rich in the middle of 3rd gear it seems.. I wondered if it took that long on each run to get "hot" enough to kick in COTP or there was some sort of timer involved.

Joecar, I see that! I'm glad I got this figured out.. it does pull a little better on the top end now that i'm leaned out.. i'm going to have to hurry and make another trip to the track soon to see what I gained.

And, sorry about the pid channel count.. I guess I forgot to get rid of something.. I usually never go over 24.. I guess I was in a hurry! I'm going to log it again in a day or 2 (I wait until night time since we have been over 100 degrees here already) just to make sure.

[joecar]

I was wrong, it looks like COTP may be reflected in commanded AFR...

see this: showthread.php?p=97048#post97048

It's a little confusing because it doesn't always show up and there's no discovered COTP AFR table.

[Chris81]

Yup, its a weird deal.. I've logged mine many more times with COTP turned off and the AFR has always commanded what I wanted it to.

[5.7ute]

I was wrong, it looks like COTP may be reflected in commanded AFR...

see this: showthread.php?p=97048#post97048

It's a little confusing because it doesn't always show up and there's no discovered COTP AFR table.

I had a quick look through the PCM map I have for the ls1 and there is a few tables in regards to COTP that we dont show in efilive. From the small descriptions evident there is a filtered multiplier at play & not a base AFR that I could have easily added in a cax file. This has put it well out of my range of skills to easily implement.
I have emailed you a copy with the addresses of the tables to have a look.
Cheers Mick