"no one" wrote in message
...
Geoff, show me the evidence O2 sensors are primarily for cat performance.
If you've ever seen a fi system go into a bad full rich open loop state,
you'll see the cat is REAL efficient. Like white hot efficient.

Not a conventional three-way catalyst. Once it goes rich and all the stored
oxygen is gone it loads up with carbon really fast and it cools off. In
fact, excess fuel is used to for catalyst protection when it gets too hot.
I didn't read the posted link but hopefully it included little story on the
oxygen-bucket theory. Sometime in the near future (post-Super Bowl) I'll
find the catalyst efficiency vs. lambda charts online and post a link - TWC
efficiency diverges quickly from stoichiometry.