O2 Sensor Readings Tuneecu

Discussion in 'Technical Help' started by Red Thunder, Jun 1, 2020.

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  1. Red Thunder

    Red Thunder Crème de la Crème

    Dec 2, 2014
    2,035
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    High Wycombe
    I just ran TuneECU on my Speed Triple 2010 to remove an error code and see the general health of the engine
    It has been running rough after a couple of months non use- when throttle at 0% (stopped at lights etc.) the engine would just die no tick over. An engine management light came on so thought I would investigate

    TuneECU showed error with Fuel Mass Sensor, I cleared the error and TPS, started the engine to run a diagnostic
    Only thing to note is the O2 readings are -26, -26, +25
    So I read this as cylinder 1&2 running lean and cylinder 3 running rich
    Everything else was on the ball, the cylinders are all perfectly balanced so no issue there
    I can only presume they are not burning even. When the motor has cooled I will remove the spark plugs and see what condition they are in
     
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  2. crispey

    crispey crispey creme de la creme

    Nov 6, 2014
    7,198
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    Simple things first, having sat for a while, a bit of cloggy fuel in there? If you haven't yet, give it a good clean out or long run
     
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  3. Tricky-Dicky

    Tricky-Dicky Crème de la Crème

    Dec 12, 2016
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    Norfolk UK
    Kind of depends how the tune ecu software reads lambda voltage and what the interpretation is of those readings a narrow-band lambda will read roughly 0.2v which is lean to 0.9 volts which is rich all the ECU does is switch the injector duty cycle to try and keep the AFRs at around 14.7 which is stoic,
    Its will always be switching between slightly rich to slightly lean as narrow band is not really suitable for accurate tuning and besides i believe the ECU only uses lambda feedback up to around 1500 RPM.

    A failed Lambda sensor will read 0.9v or more and the ECU will run permanently rich mixture until the map is open loop.
     
  4. Red Thunder

    Red Thunder Crème de la Crème

    Dec 2, 2014
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    ...last time I replaced the air box, it seems I forgot to reattach the air mass sensor
    Engines don't run well with sensors not attached
    :neutral:
     
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  5. Tricky-Dicky

    Tricky-Dicky Crème de la Crème

    Dec 12, 2016
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    Surprised it ran at all with MAF disconnected.o_O
     
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