oxygen sensor query

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PeterM
OneWave
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Joined: Fri Jun 26, 2009 2:51 pm
Location: Saddleworth

oxygen sensor query

Post by PeterM »

Hi

If a zirconia o2 sensor complete waveform is biased towards the rich [low in o2] in closed loop and the ecu leans out to maintain the A/F ratio, how come the o2 waveform appears to stay the same i.e. still showing a rich reading at a steady 1500rpm.

Appreciate any help offered.

Peter.

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Matt Fanslow
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Location: MN

Re: oxygen sensor query

Post by Matt Fanslow »

Can you verify with an exhaust gas analyzer that the trim adjustment "worked"?

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Autonerdz
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Location: Washington State USA

Re: oxygen sensor query

Post by Autonerdz »

Hi Peter,

Not sure I fully understand the question. Is the O2 voltage always high, or does it switch normally and just spend more time high than low?

If it is still switching but biased high by spending more time high than low, this could be normal strategy.

If it is high and not switching, even with fuel trims negative in closed loop, then probably the O2 has a problem or the PCM can't compensate.

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