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 10:57 PM
Subject: Re: Switch ratios

Thanks
Grumpy


>Yes.
>
>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
>>>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!
>>>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).