Buy/Borrow your O2 Sensors?
 

Any 993 owners that have switched to Cat bypass pipes with unused post-cat O2 Sensors?

I'm interested in buying (or even borrowing) your sensors so I can pass smog with my car in CA.

Thanks!

Don

The post O sensors will always be electrically needed even on a cat bypass.

They are generally just tied up out of the way(not installed in the pipe but conected electrically

I posted about the heating element connections over on Rennlist. Don't know if that is the problem or not.

Bill - since the sensor are needed electrically, do you think it makes sense just to have bung holes welded into the cat bypass pipes so the sensors can sit in a "safe" environment?

Thanks,

Don

This is why I avoided an OBD2 car.

To the best of my knowledge the downstream sensors need to be connected electrically but not screwed into the pipe.

I have heard contradictory reports on how well this works, most report no CEL issues, but there have been a few that reported otherwise.

Alon over on Rennsport also reported a distinct odor to the exhaust. form remmoval of the cat.

Neither of mine has a cat(both OBD1 though) and i have no issues w/ the exhaust odor thing.

I can't imagine passing Ca. emission inspection w/o a cat. or w/ any CEL

Yes, I'm sure I won't pass CA smog without a cat or the O2 sensors.

But once I pass, I'm wondering if instead of tying them up and out of the way, why I couldn't just install two additional bung holes and leave them in the cat (along with the two upstream sensors).

The purpose of the downstream sensors is to verify the function of the cat. The DME compares upstream w/ down and is looking for clean air downstream, if it doesn't see that it throws a CEL.

By having the downstream sensors connected but out of the exhaust, the system is fooled into thinking that the cat is present and functioning properly.

Ah - a blind man sees. After I get replacements I'll wind them up and get them out of the elements. Many thanks Bill.