Results 1 to 9 of 9

Thread: O2 Sensor cals & min/max limits

  1. #1
    Tuner in Training
    Join Date
    Dec 2019
    Location
    Newport News, VA
    Posts
    14

    O2 Sensor cals & min/max limits

    Greetings!
    Have been trying to make heads or tails of these values as in tuning it gives a small explanation but that is not clear always in how it affects the ECU decisions.

    Have an 06 GTO and the o2 sensors have a min/max setting at Min Rich/Lean 300 & Max Rich/Lean 650 under FUEL>>Oxygen Sensors>> rich/lean vs. Airflow. Are these values also maximums or minimums for the ECU in fueling between banks 1 & 2? Also I have noticed some tunes have static values while others have incrementing ones on the bank1 & 2 of LS series engines. Some have 450 static while others have different values like mine 300 & 650 etc. Any insight on these values and their proper tuning or dialing would be greatly appreciated.

    I have lost my original downloaded stock file because of a computer change and the ones I have found online have irregularities that have already messed me up until I learned the hard way and found them. Either way I am wanting to learn this VERY much and so need to know as much as possible and appreciate the time and help you give.

  2. #2
    The min/max define the bounds of the switching points. The tables above those define switching points versus airflow mode. You can tailor the airflow mode tables to suit your liking, but the min/max values act as a limit to what is being requested in the airflow tables.

    I find these tables useful for two things:
    1) adjusting switchpoints to get narrowbands to match widebands.
    2) leaning out the idle airflow mode area (low switchpoint #) to help with the false lean / actual rich condition that comes from a cam

  3. #3
    So my 300 min or 650 max lean/rich set point once it falls below or above this Value then switches to the VE table or the MAF depending on whether I'm using SD or MAF for my calculations of VE?

  4. #4
    Huh? Nope, not related. It's always using the airflow model regardless of these settings. These settings simply tell the ECM at what point to switch from a rich condition to a lean condition based on the natural switching feedback of the o2 sensors. It's akin to a sensor offset.

  5. #5
    Tuner in Training
    Join Date
    Dec 2019
    Location
    Newport News, VA
    Posts
    14
    Okay so I have heard that at WOT for instance that a sweet spot for AFR on 06 GTO is .890-900 mv on the narrow bands. WIth that being said then shouldn't I change my max rich to 900 so it then tells ECU to go leaner?
    Someone said I can tune in the switch points to match with my Wideband but am unsure what they meant. Best I can tell is I would adjust or tune the fields for my 06 GTO at Fuel>>Oxygen Sensors>> Min/ Max Lean or Min/ Max rich/lean Bank 1 & 2? With the banks it is in a voltage range 0-64 and am totally lost on how these can be transposed to the MV from the steps of the narrow band?

  6. #6
    Lots of stuff to unpack here:

    1) Don't use your narrowbands to tune WOT. Use a wideband. There is not really such a thing as a "sweet spot" for narrowbands when they operate outside of their narrow band. It is true that the narrowband output correlates to wideband output, but it is not absolute. You can't say that a certain mV output on a narrowband is going to match up closely enough to where you actually want to be in terms of WOT lambda. Bottom line: only use a wideband for WOT tuning.

    2) Changing these O2 sensor feedback settings won't do anything to adjust open-loop fueling. WOT/power enrichment fueling occurs in open loop in a system with narrowband O2 sensors, not closed loop. The reason for this is as explained in #1- they aren't accurate feedback devices for anything other than a narrow band surrounding lambda=1.0. These O2 parameters you are asking about only affect closed loop fueling.

    3) Yes, you can tune the switchpoints to make the NB's match your WB('s), within 1.5% or so in my experience.

    4) 0-64 refers to the airflow mode, not a voltage. The value you input in those Bank 1/Bank2 tables is a voltage that corresponds to the airflow mode (0-64... see the Mode vs. Airflow table to determine which airflow mode you're in at any given airflow).

    5) To make your narrowbands shift richer, add to the switchpoint. For example, let's say at a forced constant 450mV narrowband switchpoint, your wideband averages 1.01 lambda during a steady state cruise in closed loop for 30 seconds. You could change your switchpoint to 550mV or 600mV for example to bring that down to 1.00 average.

    6) Let's say it's the other way around. If your wideband averages 0.99 during a steady state cruise in closed loop, you could force your narrowbands to switch leaner by setting it to 350mV or 300mV for example, to move that average to 1.00.

    7) You can also use a low switchpoint to help pull fuel out at idle airflow modes with a cam. Combined with EOIT, it helps eliminate a raw fuel smell at idle.

    Hope that helps.

  7. #7
    It does very commander mark. Correct me or extrapolate where possible please.

    1) I'd NEVER tune with narrow bands and use my Wideband but needed to understand the 300 and 650 limits in correlation to my tune.

    2) Closed loop is where the narrow bands make adjustments once engine is warmed up and using all it's sensors to make AFR to it's commanded mark.

    3) since the set points are at 300 and 650 respectively then after I do MAF, SD and finally VE table tunes I can then check them out and move them if needed or should I do that in between somewhere?

    4) So the bank 1 & 2 tables 0-64 actually use those voltages from ? to determine whether it's in VE, MAF or SD nodes then? If so where do I check that when engine is running to double check and be sure that my current tuning logging is being setup and recording the right things?

    5 & 6) very nice thanks much for the details. Now WHEN during my tuning is it best to make these adjustments? After MAF but before SD?

    7) What's EOIT? Also it seemed like my tune had a straight 450 across the board on bank 1 & 2 and my Stoich was also 14.7 straight across. Would there be any advantage to changing these values in bank 1 & 2 instead of straight 450 to different voltages like on a 08 Hummer or 13 Corvette?

  8. #8
    Quote Originally Posted by cynicslullaby@gmail.com View Post
    It does very commander mark. Correct me or extrapolate where possible please.

    1) I'd NEVER tune with narrow bands and use my Wideband but needed to understand the 300 and 650 limits in correlation to my tune.


    2) Closed loop is where the narrow bands make adjustments once engine is warmed up and using all it's sensors to make AFR to it's commanded mark.
    This is an accurate statement. To add to it: once you shove your foot to the floor, it's no longer in closed loop, and it doesn't use the O2 sensors to adjust fueling anymore.

    3) since the set points are at 300 and 650 respectively then after I do MAF, SD and finally VE table tunes I can then check them out and move them if needed or should I do that in between somewhere?
    I'd probably just set both of them at 450 for now and worry about it later or not at all. Most big shops don't even touch these. Also, I'm not sure what you mean by MAF and SD and VE tuning. Unless I'm missing something, SD is equivalent to VE, so you do MAF and VE, or MAF and SD, but not MAF and VE and SD.

    4) So the bank 1 & 2 tables 0-64 actually use those voltages from ? to determine whether it's in VE, MAF or SD nodes then? If so where do I check that when engine is running to double check and be sure that my current tuning logging is being setup and recording the right things?
    No, neither the airflow modes (0-64), nor the voltages you put in those tables have anything to do with whether you are in MAF or blended or VE modes. Based on my guesstimate of where you're at with your tuning and tuning knowledge, I'd just set the min/max to 450, leave these bank 1 and bank 2 tables alone, and come back to them much later. It won't hurt you- all of this stuff is fine-tuning that only us hobby-tuners bother with, honestly.

    5 & 6) very nice thanks much for the details. Now WHEN during my tuning is it best to make these adjustments? After MAF but before SD?
    I'd save it for dead last, if at all.

    7) What's EOIT? Also it seemed like my tune had a straight 450 across the board on bank 1 & 2 and my Stoich was also 14.7 straight across. Would there be any advantage to changing these values in bank 1 & 2 instead of straight 450 to different voltages like on a 08 Hummer or 13 Corvette?
    End Of Injection Timing. It determines when the fuel injectors fire during the rotation of the motor. Honestly, if you don't have a cam, don't even bother with it. Regarding the voltages, as noted above, I'd just set both tables and your min/max to 450 and leave it be while you're tuning. Or if you just set the min/max to 450, it effectively overrides the Bank1/Bank2 tables.

  9. #9
    3) I was pretty sure VE or volumetric efficiency was SD or speed density tuning but never hurts to inquire.
    4&7) these set points are boundaries for a min or max amount of fueling change between telling ECU go lean or go rich then?
    Also if I were running at 430mv on narrow and and showing stoich running down highway wouldn't a good adjustment to the min lean value be moved up from 300 to 400? Same concept for the rich side to move 650 down to 550 say?