Switch ratios

[Bruce Plecan]

-----Original Message-----
From: David A. Cooley <n5xmt at bellsouth.net>
To: gmecm at esl.eng.ohio-state.edu <gmecm at esl.eng.ohio-state.edu>
Date: Thursday, April 01, 1999 10:41 AM
Subject: Re: Switch ratios

So then, the rear O2 since it is dealing with thourghly reacted gases would
need to be the "superior" sensor?.
  So it's slew rate at Stoich. would need to be much less for the ecm to see
the cat con effeciency?.
Bruce


>OOOH OOH  MEMEMEMEME!!!
>The PCM looks at the Stoich crossings of the pre-cat O2 and the post cat
>O2...
>Post cat most likely will be pretty steady.  If the post cat starts
swinging
>it's output close to what the pre-cat sensor see's, then it flags a cat
>failure.  PCM will have params on how close the post-cat O2 must be in
>cycling to the pre-cat to set the code.
>There... 70 words!


>-----Original Message-----
>Subject: Switch ratios
>>Can someone in 100 words or less explain what a swtich ratio is?.
>>This is in reference to comparing O2 sensors (post-pre cat converter).
>>Thanks
>>Bruce