Buy/Borrow your O2 Sensors?

[Don Plumley]

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

[Bill Verburg]

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.

[Don Plumley]

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

[Bill Verburg]

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

[Don Plumley]

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).

[Bill Verburg]

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.

[Don Plumley]

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