O2 sensors at WOT?

[Mark Wilcutts]

On Wed, 4 Nov 1998 PMDRACER at aol.com wrote:

> In a message dated 11/3/98 9:56:08 PM Pacific Standard Time, bartlett at slip.net
> writes:
> 
> <<  Might be because WOT enrichment pegs the O2 sensor to the rich side.
>  
>  And then the 02 sensor would try to trigger the ECM/U to lean the mixture
>  which, presumably, you wouldn't want.  Hence the open loop at WOT ?
>  
>  Jeremy >>
> 
> Actually, the ECU is progtrammed to IGNORE the O2 input at WOT. The ECU is
> programmed to err on the rich side. A rich mixture is necessary for max power,
> but a rich mixture will not do internal engine damage like that of a lean
> mixture will.

Yep. Another reason for the richer mixture at WOT is to reduce the exhaust
temperature (compared to stoich) thus preventing damage to the O2 sensor
and catalyst.