Results 1 to 2 of 2

Thread: o2 switchpoints

  1. #1
    Advanced Tuner
    Join Date
    May 2005
    Location
    Conway, AR
    Posts
    347

    o2 switchpoints

    Ok I have my MAF and VE dialed in as perfect as it gets. Truck feels much much more responsive than when i thought I had it perfect with narrowbands! I am using the AEM wideband now.

    Now my question, The fuel trims are +1/-1 but I still have an AFR error of 2% across the board in closed loop. Right now my o2 switchpoints are at 451 across the map on both banks. To get the AFR error down to I need to raise or lower the switchpoint so the trims match my error %?

    Chris
    2009 Silverado Crew Cab 5.3L, stock.

  2. #2
    Senior Tuner
    Join Date
    Nov 2002
    Location
    Central Florida
    Posts
    2,503
    No, the O2s should travel above and below just fine.
    You can crutch a sleepy O2s problem a little by setting
    the threshold lower but when they go to sleep, it's
    not a matter of millivolts, it's more like bang-bang,
    no-bang.

    I did bias my switchpoints lower to trick it into a
    slightly leaner cruising. But can't say as it did anything
    significant. You have to go mighty low to make any
    AFR difference as the switching curve is pretty sharp
    at the lean end.

    I don't believe you can call any hobby-grade wideband
    (which most of them are IMO until you get to the gas
    analyzers) a 1% instrument. Just bias the error so that
    you never get a positive LTFT onto WOT (all trims <= 0)
    and call it good enough.