O2 sensor tuning with Headers

[schpenxel]

I'll have to try that one

[JBZ]

yeah, ill try and get all the logic in today if I can. thanks again sevinn

[sevinn]

yeah, ill try and get all the logic in today if I can. thanks again sevinn

No problem. There is probably something better than vehicle mph to use but it seems to have worked pretty well for me; it's easy enough to adjust these filters after a drive to get a better idea of the data if you need to.

[sevinn]

Got me thinking about it... You could probably end up with similar (if not more accurate) results by looking at the slope of commanded throttle position as well as average commanded throttle position. I'll test it out and see how I feel about it

Log commanded throttle position and the following filter would do it I think assuming these pids are all the same across our ecus:

[2148.156] < 50 AND [2148.156.avg(500)] < 50 AND [2148.156.avg(-500)] < 50 AND [2148.156.slope(500)] = 0 AND [2148.156.slope(-500)] = 0

[JBZ]

killer, I just dropped it in...checked it with my scan from today and Viola it works...thanks again. and because of the steady state calc it logs a lot less data. that will be interesting to try on my virtual VE table histogram set up as well...once I man up and attempt to adjust it.

[sevinn]

killer, I just dropped it in...checked it with my scan from today and Viola it works...thanks again. and because of the steady state calc it logs a lot less data. that will be interesting to try on my virtual VE table histogram set up as well...once I man up and attempt to adjust it.

For vve tuning you may want to drop the times in the filter because I wasn't getting enough data at all on the street with half a second, so just be mindful of that. 250ms average/slope is better than no filter at all.

[schpenxel]

Got me thinking about it... You could probably end up with similar (if not more accurate) results by looking at the slope of commanded throttle position as well as average commanded throttle position. I'll test it out and see how I feel about it

Yeah, just has to look at it over a long enough period of time, I think anyways.

[JBZ]

I need to get this o2 thing worked out first and make sure my o2s are reading the correct data. Then i can start vve tuning. Thanks for tour help fellas.

[GHuggins]

Sevinn, that equation looked familiar I'll have to give your filtering function a try - I've honestly never been much good at coming up with filters...

A thought Carson... Are there any filtering threads for the new scanner?

[sevinn]

Sevinn, that equation looked familiar I'll have to give your filtering function a try - I've honestly never been much good at coming up with filters...

A thought Carson... Are there any filtering threads for the new scanner?

I thought it was a thread you were active in that I got those equations from I just didn't want to give the wrong person credit! Lol

[schpenxel]

Sevinn, that equation looked familiar I'll have to give your filtering function a try - I've honestly never been much good at coming up with filters...

A thought Carson... Are there any filtering threads for the new scanner?

I don't think so.. who wants to make one?

[JBZ]

one of you 3 should, you're all a lot smarter than this guy right here.

so would you guys mind taking a look at a log from yesterday and tell me what you think about the O2 spacing? here are the settings I have now

Closed Loop Proportional Base vs. Airflow Mode (multiply x .8)
Closed Loop Mode vs. Airflow (decreased to DOD settings for lack of better option or knowledge)
Closed Loop Integrator Delay vs. Airflow Mode (multiply x 1.42) this is the only one I have changed in the last couple of days and changed it from 1.40 to 1.42

by the way I brought all my switching voltages down to 350 mv...absolutely no change in switching that I see in any log. is there something that we are missing in our tune file that GM has that ACTUALLY affects switching voltage?

thanks

[schpenxel]

Did you change both bank 1/2 and min rich/lean mV?

Try lowering it some more--I've never really seen a difference when changing it either, though maybe going further will do something?

[JBZ]

Did you change both bank 1/2 and min rich/lean mV?

Try lowering it some more--I've never really seen a difference when changing it either, though maybe going further will do something?

yes, here is what I got, am I missing anything?

[schpenxel]

I think that's it--try like 250 and see what that does

[GHuggins]

Above 30mph good looking, below not as great - I typically don't worry about that a whole whole lot - at least not personally unless a cam or something is causing fits from the switching O2's...

Another thought on this since your comparing open loop to closed loop - I'm seeing something in the averaging neighborhood of -3 to -6 percent fueling - fine for your setup - even what I try to shoot for the majority of the time - this will make it your fueling go to the .95's that your seeing... Just for experimental sake - dial you idle area of your MAF in until it's +/-2% on the short terms - put into open loop and then see what the air fuel is...

[JBZ]

So what looks wrong below 30? Spacing to tight...to narrow...or does the porportional look wrong? Would you maybe have an example even a screen shot of what looks right? Thanks

[GHuggins]

O2's aren't switching fast enough and are staying richer longer - try increasing proportional back to stock or slightly higher as long as it doesn't cause bucking or surging issues... Your 30+ mph areas are what your looking for while idling and slow cruising or rather high gear low rpm cruising... Sometimes if missing cats or when combined with large overlap cams it may all but be impossible to get that area...

Wish I better understood which portions of the airflow mode tables controlled what load or rpm "breakpoints" so I could better dial them in myself...

[JBZ]

O2's aren't switching fast enough and are staying richer longer - try increasing proportional back to stock or slightly higher as long as it doesn't cause bucking or surging issues... Your 30+ mph areas are what your looking for while idling and slow cruising or rather high gear low rpm cruising... Sometimes if missing cats or when combined with large overlap cams it may all but be impossible to get that area...

Wish I better understood which portions of the airflow mode tables controlled what load or rpm "breakpoints" so I could better dial them in myself...

yeah ive now been trying some random things like dropping in factory Zr1 LS9 P&I settings just to see what happens, actually quite an improvement in low RPM swinging but in my opinion way too fast up top it also knocked down my random misfire numbers but made them hit more often. I put the stock P settings back in and think its actually getting to the rich and lean a little faster which completely makes sense. the integrator delay that I had (X 1.42 of the stock V settings) in there seemed ok in the higher cells but too big in the lower section. I actually don't think it ever sees the 0 cell (1200 something number) with just the cold air and pulleys that I have.

this is how I think these tables are calculated (in the screenshot) this is just a guess. why GM didn't just put 0,8,12,16,24,32,40,56,64 in those cells is what I'm not sure of. but if I look at my logs the swings do seem to coincide with the mass airflow lb/hr in the table. so my only guess is that if you want to stay in a particular cell longer moving the numbers in the table lower might hold them longer.

[coolmo]

Yes, that's what I think also. At whatever airflow mode you are at, say 8 (32-63lb/hr), the pcm uses airflow mode 8 values in all the charts. If you are at 32 (~240lb/hr) it uses mode 32 values in all the charts.