Closed loop goes rich not lean????

[ddnspider]

Reference this thread for my setup and history
https://forum.efilive.com/showthread.php?27603-Blower-Larger-Cam-Timing-Theory-with-Pics&highlight=

I've got the tune pretty much down pat, cold start is great, idles great, A/F is good, timing is where I want it. But for the life of me when I try to go closed loop all it wants to do is pull fuel at idle and cruise, somewhere in the neighborhood of 10%. With longtubes and mods I usually see it trying to dump a bunch of fuel when you go closed loop. Has anyone seen what Im seeing, that it will trying to lean it out with closed loop? Is it just a matter of adjusting the O2 switch points to something high like 5-600mV to get it to richen up the idle and cruise when in closed loop? Thanks for any info.

[joecar]

Post log and tune.

[ddnspider]

Post log and tune.
This is a "warm" start as I had been messing with the MAF table and other crap to try and get it resolved. Notice the air fuel before the O2's start switching and it goes closed loop and then the air fuel after. It smells a little lean from inside the car so I think the wideband is correct. Its a brand new LC1. I can compare with an LM1 I also have if needed. I did the 02 OS flash update from the 99. Also note the air g/sec and injector data is scaled 30% and its a MAF only tune.
2125021251

[ddnspider]

Verified the air fuel with a lm1 in place of my new lc1 and same result.

[ProperTuningOG]

How are you receiving the wideband data? Serial or analog?

[ddnspider]

How are you receiving the wideband data? Serial or analog?
Serial only on both widebands. I've tuned quite a few cars now and this one runs great, especially given the cam and blower, but this closed loop lean business is so weird to me.

[ProperTuningOG]

CL mode at idle is about 30. I think you are adjusting the wrong part of the switch point table. Adjust the switch point or adjust the CL mode table to make the switch point table proper. Remember lower vacuum cams at idle want a leaner switch point to match the wideband.

Also, when the wide band shows mid-high 14s the narrows never dip from high mv.

[ddnspider]

Ah crap,well now I just feel lazy. I thought about CL mode and figures there was no way it was that high given that the time is scaled 30 percent, but didn't actually check it. One thing you said confused me. You said I want a leaner switch point? My understanding was the switch point table allows you to tailor what the car thinks is Rich vs. lean. I.e if I raise the switch point to 600mV, the car will spend more time on the lean side and I will have positive fuel trims, is this true?

[ddnspider]

I made a change to the switch points at CL mode 24 and 32 and it appears the crusing AFR is better than it was, not perfect but in the right direction. Idle still is leaner than I would want. Something of interest in the logs is at frames 3859-3943 right when the car comes to a stop. The AFR and O2's go rich like 900mV and the AFR 13.5 to 15 and then all of a sudden the O2's start switching again. This is also repeated starting at frame 6830. Should I keep pushing the switch points up until the fuel trims comes back to where they should be?

[ProperTuningOG]

The log makes it seem like you are running on 2 different ground plains or something is off voltage wise with the wideband or narrows. I highlighted an area to show this. If the condition was lean the narrow mv would not be 900.

I would disable closed loop and start looking at voltage difference under steady state with no O2 switching. If things even out as they should and its only an idle condition, then at least you have narrowed it to that. If they have not and you are still showing 900 mv condition under a steady state 14.7-15 then something is going on with data collection.

21256

[ddnspider]

Checking voltage potential differences at steady state with no Dyno is going to be tough. I thought when you're open loop the O2s will drift all over to whatever they please, they just don't switch. I have read that there's been a lot of issues with the new LC1s, but I hoped I typed that when I put my lm1 in its place and am using serial data. Any chance the factory settings in the LC1s need to be changed?

[ProperTuningOG]

That would not be a question for me. I stepped away from the same manufacturer a few years back for similar constant inconsistencies across the product range.

[ddnspider]

That would not be a question for me. I stepped away from the same manufacturer a few years back for similar constant inconsistencies across the product range.

Well that stinks. I'll try the open loop stuff and report back in a couple days.

[joecar]

I've been having problems with my newer LC-1.

My older one is ok and works great.

[ddnspider]

I've been having problems with my newer LC-1.

My older one is ok and works great. That's unfortunate. I've been hearing that alot lately. I may try and see if I can reprogram mine or something. Did anything jump out at you in the tune? I get my new electric fan Thursday so I'll probably try logging either Thurs or friday.

[joecar]

I'm still looking.

[ddnspider]

Update. Went back OLMAF and added another ground from the block to the battery post and it seems to be helping when OL at least. Also worked out some belt slip issues and it pulls hard now. Did anyone see anything else in the tune that would have made it act wierd in CL? Lasted OL log attached.

21288

[joecar]

That's unfortunate. I've been hearing that alot lately. I may try and see if I can reprogram mine or something. Did anything jump out at you in the tune? I get my new electric fan Thursday so I'll probably try logging either Thurs or friday.Nothing big jumped out at me (sorry it took so long...).


B5001 MAF: table is a little bumpy, should be smooth, but PCM performs smoothing/filtering on MAF anyway.

B4105 O2 Switch Point: try setting all of those to 450 mV.

[joecar]

Update. Went back OLMAF and added another ground from the block to the battery post and it seems to be helping when OL at least. Also worked out some belt slip issues and it pulls hard now. Did anyone see anything else in the tune that would have made it act wierd in CL? Lasted OL log attached.

21288I'm now looking thru this log...

[ddnspider]

Nothing big jumped out at me (sorry it took so long...).


B5001 MAF: table is a little bumpy, should be smooth, but PCM performs smoothing/filtering on MAF anyway.

B4105 O2 Switch Point: try setting all of those to 450 mV.

My guess is belt slip is playing a role in the MAF being a bit bumpy, but ill take another swag at it. Something I was thinking of is when I did my scaling, I need to verify that I scaled the CL mode table. I'm wondering if thats why the fuel trims were so far off in CL vs. the wideband.

[ddnspider]

Thanks!

[ddnspider]

Bumping this thread from awhile ago with an update. Set up a hybrid tune. OL idle below 1200rpms and closed loop above that. When the setup went closed loop it was leaning out the cruise AFR to mid15s to 16. I logged o2 switch points and CL mode and went back and adjusted the switch points to what the log said and it's better now. Still a little lean, low 15s, but it's cruise so not bad. I found a couple links on tech that helped me out. I may still try raising the switch points more and see if it helps even more.
https://ls1tech.com/forums/pcm-diagnostics-tuning/1842325-tuning-o2s-headers-closed-loop.html
https://ls1tech.com/forums/pcm-diagnostics-tuning/603765-who-can-explain-airflow-modes.html

[ddnspider]

The only thing I haven't figured out is the fuel trims only pull fuel they never go positive which seems odd to me.

[joecar]

Please post your tune file.

[ddnspider]

Tune attached. Ignore the MAF table, its maxed on a scaled tune and I need to move to an LS7 MAF to get more range.
21747

[ddnspider]

Anybody see anything that would cause this?

[joecar]

Try setting B4105 to 450 mV in all cells.

[ddnspider]

Try setting B4105 to 450 mV in all cells.
I think I had it like that before adjusting and the fuel trims we're WAY off and it was pulling a bunch of fuel running lean. As part of scaling the tune I also scaled the closed loop mode table which shifts airflow to numerically lower closed loop modes. Would this have any impact?

[joecar]

Try setting the CL mode table back to stock to see what happens.

[ddnspider]

Try setting the CL mode table back to stock to see what happens.
Thats a good thought, I hadn't considered that. I will give that a try. Thankfully its back in the 70's here now.