Emissions (long - but need advice on somthing new)

[Raymond A. Kawski]

Jez wrote:

Snip:
> basically injects unmetered air into the exhaust stream,

Snip:
> When removing the PAIR the car will run rich without the
> PAIR.

Hmmm anyone else see anything wrong with these two
statements?  If PAIR is injecting "unmetered air" then how
could a change in mix occur?  Since the ECU doesn't know
how much air was injected how does it control the mix?
Also its injecting the air into the exhaust stream
*after* the O2 so how could it correct a rich condition?

RK
Confused.