Air Flow Measurement

[kleenair at ix.netcom.com]

> reads the oxygen content of the combustion products and outputs a
> voltage. But us California folks have this horrible pump that forces
> air into the headers to cut emissions, so how can the O2 sensor give an
> accurate reading??. Any comments anyone.
> 
> Neil Powell <Neilaura at ix.netcom.com>

Usually, air pumps are connected to the exhaust through a diverter (air 
bypass) valve.  The computer simply redirects the air back to the air 
cleaner when in closed loop operation, so no excess oxygen is pumped to 
the exhaust.  

Alternatively, I saw a 1996 truck (I forget the brand), that pumped the 
air down stream of the O2 sensor.