O2 sensor tuning with Headers

[schpenxel]

Yeah, it's airflow "mode" like you were thinking

[JBZ]

Cool well that almost makes it easier to set up swings then modifying the p and i gains...i mean i will still modify the gains but alot smaller changes and line up the airflow mode to hit the cells in the gains i want for the engine speed i want.

Finally i figured something out.

[coolmo]

Good idea on the ZR1 settings. I think I'll try the 'O2 rich/lean' mv settings as well. They change with airflow mode and ECT. Mine are just set at 450mv. ZR1 settings are at 600mv at cruise speed and 200 deg ECT.

[coolmo]

Actually looks like they switch around 525-550mv. I was looking at my stock 'cold offset' table.

[JBZ]

The file i pulled was a 2011 and it had switch high/low at 250/685mv and bank to to bank were first 3 cells at 400 and the rest were 450. Its strange how gm changes things. They even did that with the v switch points in the later years

[coolmo]

Yeah that's the same file I pulled. Remember you have to add the value from the 'cold offset' table. 450+100(183.2 deg F)=550mv.
The 250/675 high/low is just the min/max allowable.
That's how I understand how it works anyway.

[JBZ]

Yeah that's the same file I pulled. Remember you have to add the value from the 'cold offset' table. 450+100(183.2 deg F)=550mv.
The 250/675 high/low is just the min/max allowable.
That's how I understand how it works anyway.

Good call forgot about the cold offset table. Need to drop that down to zero or drop the left/right banks by 100. I want a stoich or leaner idle and stoich switching for the rest of cl operations. Have not seen any changes and already dropped them down to 250 mv across the board. I set up a histogram to track my average mv plotted against my maf htz so i could see on average when i was rich lean. I have not seen any changes as of yet and went from 450 down to 250.

[coolmo]

Yeah that's the same file I pulled. Remember you have to add the value from the 'cold offset' table. 450+100(183.2 deg F)=550mv.
The 250/675 high/low is just the min/max allowable.
That's how I understand how it works anyway.

I may be wrong on that. It may only use the cold offset table for the first few seconds after startup. Maybe somebody who knows can let us know.

[coolmo]

Good call forgot about the cold offset table. Need to drop that down to zero or drop the left/right banks by 100. I want a stoich or leaner idle and stoich switching for the rest of cl operations. Have not seen any changes and already dropped them down to 250 mv across the board. I set up a histogram to track my average mv plotted against my maf htz so i could see on average when i was rich lean. I have not seen any changes as of yet and went from 450 down to 250.

You may need to go even lower. Check out these stock tables for my ZL1. 61 mv at 0 & 8.

zl1 o2 r-l.PNG

[JBZ]

You may need to go even lower. Check out these stock tables for my ZL1. 61 mv at 0 & 8.

zl1 o2 r-l.PNG

Yeah those are the left/right banks that are in the later V files...i think 2012 and later. Although at this point im note sure anything actally affects switching voltages.

I have already dropped the offset down to 0 for anything above 183 degrees.

[schpenxel]

Did it do anything when you went that low?

[JBZ]

Did it do anything when you went that low?

No...no noticable change in o2 mv.

Now im trying to figure out if my random misfire count has to do with min/high low settings, integral delay, porportional gains/all 3 or maybe o2 temperature because after i put in the zr1 settings my count was less but had it more often.

Btw last night i check plugs and wires and they were all good. Seeing as how i get way less random misfires when im in OL i am almost 100% positive its do to o2's. Ive more or less made this random misfire thing my priority now.

Edit: kind of off topic but using sevinn's filtering function i do have the ltft/stft all within 2% both in the morning and afternoon on my way to and from the office. I also asked hpt support for integrator delay multi vs o2 error. Somthing i dont have in my tune file. Still wondering if integrator delay is the same as transport delay in other software. I really just think its how often the pcm switches from lean to rich and holds that state before switching. No actually how long it takes the o2,s to read the value opposed to when the pcm changed the proportion of fueling.

[JBZ]

heres a weird one.

I started my VVE tuning this morning and never got one random misfire. I currently have it in MAF fail.

is the MAF used to help calculate random misfires? my only thought is that it is not actually doing the calculations now and that is why it never logged one.

[schpenxel]

I have no idea how misfires are calculated honestly--I do know mine ran so much smoother in SD only that I never went back to using a MAF. But mine was right after an intercooler and a bend in the tubing so I think there was just too much turbulence. Some people run MAF's just fine.

I always assumed misfires were calculated by watching either the crankshaft or camshaft position sensor and picking out points that engine speed randomly drops out or isn't smooth compared to everything around it. Whether that is true or not, I have no idea

[JBZ]

I have no idea how misfires are calculated honestly--I do know mine ran so much smoother in SD only that I never went back to using a MAF. But mine was right after an intercooler and a bend in the tubing so I think there was just too much turbulence. Some people run MAF's just fine.

I always assumed misfires were calculated by watching either the crankshaft or camshaft position sensor and picking out points that engine speed randomly drops out or isn't smooth compared to everything around it. Whether that is true or not, I have no idea

I hope others may chime in, here ive been thinking its related to the 02 sensors the whole time, and changing around the gains did affect how often and the severity, also going into open loop would greatly reduce the amount of misfires...but today with MAF fail...not one single misfire.

[SSUte01]

Can't speak for E38/67, but in P01, misfire detection is disabled when the MAF is failed, so it is possible that the same is true for Gen4. Not sure.

[GHuggins]

Pretty sure it's disabled in the gen 4's too - at least I can confirm that I've had misfire problems due to plug wire burn ups while tuning in the VE and had to put the MAF back in to see which cylinder was causing the problem.....

[JBZ]

Yeah ive had none since disabling maf so that only makes sense. No worries as the majority of them are erroneous anyways and due to my headers. Thanks guys for chiming in.

[ddtech]

Your KR settings are still stock and they are rather sensitive from the factory, cut them down by about 15% and see if it helps, i did that on mine while reading plugs and its pretty much dead on.

I can take a gander over your timing maps again and see ,you may just also need to pull some out.

[JBZ]

Your KR settings are still stock and they are rather sensitive from the factory, cut them down by about 15% and see if it helps, i did that on mine while reading plugs and its pretty much dead on.

I can take a gander over your timing maps again and see ,you may just also need to pull some out.

Im really not seeing much if any KR at all lately. Every now and then i get some and i will revisit my timing maps but i have just started my VE tuning...literally just downloaded a tune in and well see how it goes. I can post up a copy of my tune tomorrow. I left my pc in the passanger seat for logging tomorrow morning on the way in.

My biggest issue right now is random misfires showing up on the scanner. Checked plugs and wires last weekend and they were all good. It mostly has to do with my 02 placement and me wanting perfection. I dont feel misfires, sense misfires but the scannner picks them up when in closed loop. If i go into open loop i may see 2 every 5 minutes so i know its a header issue. Also i never see misfires under load...they only show up cruising down the fwy.

From everything i have read timing will change with airmass calc changes so i plan to hit timing again but i want to get air and fuel right as of now. I have my timing really consertive right now and i think i would rather let the pcm take timing out even if there is no knock there rather then risk an expensive build if infact there is real KR and i numb the settings down to where it doesnt pull enough timing out. The most KR i have seen is 1.5 degrees and that was around 1600 rpm.