O2 sensor tuning with Headers

[ERIKGUNNAR]

I realize this is an old thread but info here helped me get my WB oscillations running CL with errors now under 2%. Car is a lot smoother and even picked up a few extra MPG.
No more O2s swinging into saturation before corrections. Just takes time to tune in all the gains and delays for each airflow step.

Attachment 69303

Great. Can you post the tune? I have a Z6 Z06 2008 E38

[ERIKGUNNAR]

I've been experimenting with O2 settings for a couple days now trying to improve idle, reduce AFR swings and push everything a tad leaner if possible. What I've discovered is that leaving the switching voltage at 450/450 and reducing bank 1/2 down to 50mv across the board did push the average AFR .1-.2 leaner. I then reduced the o2 limit from 2 all the way down to .01 and that made a dramatic difference. At cruise my AFR swings at most .1 point compared to over 1 point previously. It still swings about 1 point at idle but with 13 degrees of overlap and idling at 720RPM I expect that but the swings don't seem to affect the idle quality nearly as much as before. Overall the motor feels happier and more willing to rev than it ever has. I haven't found any negative consequences to dropping the limit so much. I also reduced both the int and prop airflow in various cells until I got the switching to smooth out pretty much everywhere.

Now I just need to figure out why my laptop decided to tank a dump and lose corrupt my last log file.
Attachment 61422

Hi. Morris.

Which car/ECM/Engine was this tune file for?

[GHuggins]

Erik, I sent you an email on what to adjust - at least I think it was you?

[gmorris]

Hi. Morris.

Which car/ECM/Engine was this tune file for?

418 LS3 E38 in a '69 chevelle...not likely much use to you lol.

[BigMike42]

Any cliffs? Seems like gen 4, the limit table is our ticket now?

[GHuggins]

Just watch out on the limit table - it can be too low and cause fueling to stick rich or lean... I didn't go much under 1.25 for idle and cruise airflow ranges...

[NickBoulin]

that is interesting, wonder if they expect that the purchaser will inevitably put headers on. I may try and set my limit to zero. honestly I have left my settings alone and am happy with them for a few weeks now.

here are my current settings

I know this was 2 years ago but were these settings with the 2010 CTS-V in your signature?

[bmd2_colo]

This thread really helped me get my O2s workin right since my header install- thanks to you guys workin through things.
I'm not running a blower (07 TBSS, LS3, kooks LTs, yank 3k, RPM LVL 6) but these changes woke my O2s up in the lower airflow closed loop modes.

I've performed multiple SD and MAF only narrowband tuning sessions then re-enabling both for VVE prior to changing my O2 prop stuff, my O2s are much peppier now and it does seem to react faster on tip in and it does stablize much faster where it should (+/- 1-3 LTFT between banks and max of +/- 3 LTFT from zero). I didn't have any issues with mismatched banks before hand or LTFTs hanging rich or lean, but these changes helped fix my lazy O2 LTFT behavior below 2k rpm.

Since I don't have a wideband yet, I didn't change my narrowband rich lean switch points, my previous experience with 88-98 chevy trucks has shown that this really doesn't do much (had a zeitronix zt-2 wideband way back when), but maybe it will with the GEN 4 computers. I'm gonna get a wideband and see what AFR is displayed when the computer thinks its hittin 14.7, 0.0 on LTFT according to 450mv and then maybe adjust as necessary. Since E10 stoich is 14.1, I wonder if GM accounted for that, maybe not, maybe so.

I use the aeroforce gauge for monitoring LTFTs while driving, great tool. recommend that one

[RobZL1]

I also want to take a minute to say thanks to JBZ for figuring all of this out. (Also to GHuggins, schpenxel, gmorris, Michael_D, and others that contributed and helped along the way.) This thread was a great read and I really appreciate all the time that you guys put into this.

I had guessed/iterated at tuning these with multipliers and got fairly close with my SW headers, but after spending some effort applying the things JBZ learned, I got it even better. I attached before and after pictures with both idle and low-rpm/low-flow cruise to show the differences. The O2 swings got tighter and more consistent. I also shifted the average down a little with the switch points.

One thing I'll add that's relevant to this thread for anyone working through this stuff: make sure you get rid of rich coast-down as shown in the last picture by forcing it into the idle LTFT cells, and keeping it the hell out of FTC 15. This is accomplished by raising the LTFT Idle Cells Thresholds to speeds higher than you'll ever see- e.g., just pump 'em up over 200 or 300 or something, while keeping Enable VSS less than Disable VSS. This was just one last thing that bothered me that needed fixed.

Thanks again JBZ!!

[xc_SS/RS]

So is it a bad idea to set the O2 sensor limit to 0? I have mine at 0 and so far it runs well but I noticed the O2 switching slowed down. I'll post my tune/log when I get my laptop charged but from what I saw my fueling only showed 1-3% rich.

Car is a 2010 Camaro SS LS3. Intake, headers, highflow cats, and flex fuel equipped. I'm just trying other o2 settings out to see if it'll improve mpgs. I have it dialed in well with VVE, MAF, and WOT done.

[07GTS]

with the limit zero it wont correct for the 02 switching as fast as it may need to, its the same as setting your idle proportional corrections to zero, it may still work just not as fast or good as it should

[truth.b]

Thanks to everyone in provided input into this thread. I have been chasing random off IDLE KR for roughly a month and incorporating the techniques from this thread resolved a lot of my issues and now.

Car Setup:
- Drysump Manual LS3 in Grandsport
- Stock Airbox with Attack Blue Filter
- Stock Intake & Throttle Body
- AFe 1-7/8" TRI-Y header with cats
- Stock NPP Exhaust
- Upgraded Cam (below specs)

Upgraded Cam Profile:
Duration: 216/224
Lift: 0.553?/0.553?
LSA: 117* +4 advance
Overlap: -14


For those that are interested here are my O2 setting I'm going with for right now.




Current Tune I'm testing out -->> Build -- O2_dev8.02.hpt

[evetune1969]

Great information. thanks to everyone

[JimMueller]

I personally would like an "exact" step by step on how to best adjust it?

After reading through these 12 pages, I was hoping this would have been answered. Has a specific workflow been established to return O2 behavior to factory behavior after performance modifications? I have Banish's two books, his beginner DVD, and books from Maslic and LaSota. I recently bought the 350 page Throttle Up PDF; they supposedly bought the rights to all of Ed Mowton's research. This PDF does describe the tables, but in general only says to correct those tables for the increased O2 distance.

Do we have a step-by-step guide? In what order to adjust the Gen3 & Gen4 tables? How do we specifically determine how much to adjust the cells in each of those tables? What symptoms do we monitor to know that those values are incorrect and how to further optimize them?

[Aaron Hines]

i was wondering the same exact thing. ANYONE?

[rcodea1]

same here....or are people just using the data from JBZ and/or truth.b and leaving it alone?

~Ryan
Charleston, SC

[JimMueller]

I know mine is Gen3, but both Gen3 & Gen4 are being discussed in this thread. Here's a log from my drive to work this morning, my current tune, and the factory tune. Do I need to log anything else to dial in the O2 sensor relocation tuning? What can be improved and what are the specific steps to do that?

[MG93]

I've been lurking on this thread for a while and trying to follow the progression of what factors into the closed loop operation of the engine. I'm still a bit confused about the PID controls, and what tables to edit in order to reach a desired outcome. I glanced at the papers one user posted links to a few pages back, where it outlines the principles behind the transfer functions used.

From what I understand, the transfer function takes in a raw lambda signal, then applies a proportional derivative and integration transform to the signal and checks the output against a set value, then feeds that back into the function to work towards the desired signal.

What I'm trying to understand is situational applications, since I've been messing with these tables on my truck since installing long tubes and I have been getting p0133 & p0153 (O2 sensor insufficient response time) errors. Knowing that my o2 sensors are brand new and that I don't have any exhaust leaks, my research has led me here. When logging on VCM scanner, I notice that my bank 1 O2 sensors seem to hang high (rich) then have a nice smooth switching at the trough of the wave form. Looks kind of like this (obviously smoother, though) _,----._,----._ etc.

I have tried some suggestions here but I am wondering what could cause these sensors to hunt and maintain a richer signal than being balanced and switching like: _,--._,--._,--._

Is there a set of tables I could check?

My truck is a '99 Z71 5.3 P01 with an '02 12212156. I used the comparison summary to copy over virtually all my stock '99 tune engine tables except for the cranking (fuel/air/spark) tables. I also noticed that with the '02 OL/CL tables, the truck would set the p0133 & p0153 codes, but not with the '99 settings, so I know those codes are related to the PID scheme the computer is using doesn't see the o2 sensors the same way my '99 stock tune did.

Sorry if this is confusing, please bear with me!

[lambda1]

Hi
I installed long tubes on LS2 corvette (6.0L).
I installed a harness extensions because the wires were to short, and something is not right. I checked with VCM, that the LTFT and STFT works pretty fine, the voltage is oscilating, but.... when I checked with my wideband, it turned out, the AFR is around 16. The narrow bands are oscilating to keep the afr around 16 which is extremely lean.

I thoungt maybe it is the reason of the harness extensions, because the voltage is lower due to longer harness and I tried to lower the switching voltage, by 100mV on and on down to 150mV, but with no success. THe narrowbands still keep oscilating and keeping the fueling to hold 16AFR.

Any idea what is the reason for that?

[GHuggins]

Make sure your wideband is right for one. O2 age will effect it too. Integrator needs to be increased to represent the further distance and then lower prop limit some.