O2 sensors pre- and post-cat

[Bruce Plecan]

-----Original Message-----
From: xxalexx at ix.netcom.com <xxalexx at ix.netcom.com>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Thursday, September 10, 1998 9:06 PM
Subject: Re: O2 sensors pre- and post-cat



> If standard O2 sensors only work at a single O2 %, and the cat itself is
changing the O2 concentration in the exhaust stream, and the ECU is cycling
the pre-cat sonsor around its optimum ratio, then what does an ECU expect
the post-cat sensor to be telling it?
>
If you happen to see a 96 or later GM manual they give graphs and
limits and operation.  The ECU expects the CAT to release O2 at
a frequency. every 1 or 2 min?  If CAT does not put out enough O2
and car has less than 100,000 miles go to dealer and get a free new one.
alex

I been starring at the EK, and Y 97 manuals all day today, what areas were
they in emissions/diagnostics?.  I can't find them.
Bruce