oxygen sensor query

Ask any questions about using PicoScope Automotive software here.
Post Reply
PeterM
OneWave
OneWave
Posts: 10
Joined: Fri Jun 26, 2009 2:51 pm
Location: Saddleworth

oxygen sensor query

Post by PeterM » Mon Nov 09, 2009 4:06 pm

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.

User avatar
Matt Fanslow
OneWave
OneWave
Posts: 15
Joined: Wed Aug 01, 2007 8:38 pm
Location: MN

Re: oxygen sensor query

Post by Matt Fanslow » Mon Nov 09, 2009 4:43 pm

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

User avatar
Autonerdz
TwoWaves
TwoWaves
Posts: 343
Joined: Wed Nov 20, 2002 4:19 pm
Location: Washington State USA
Contact:

Re: oxygen sensor query

Post by Autonerdz » Mon Nov 09, 2009 4:48 pm

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.

_________________
Tom Roberts
(The Picotologist)
http://www.autonerdz.com
skype: autonerdz
THE PicoScope Automotive Authority
In North America

Post Reply