What happens if I leave my O2 sensor off?
 

Sorry to keep nagging everyone about this. But if I just plug the O2 sensor port in my test pipe with a bolt, will this hurt my mixture or DME? Anything else to worry about? Since I'm taking my cat off, I really don't care about emissions until the next inspection.

I disconnect mine for track events. Without it (at least with a 3.6), you never allow the computer to go into closed loop mode. The effect is that the car runs a little richer.

From my experience the car will run richer as Jack says.
But do not do it with your Cat on as it will damage the Cat!
The car will rev slightly higher and performance may be better when driving hard!.
If you have bad idleing problems it may be a good temporary solution with the emphasis on temporary
regards
Ben

Godd to hear from you, Ben!

More, Warren. I want to hear what you say will happen if I do this.

Richard,

Basically, what you will be doing is running on a single, default fuel and ignition 'map' for the engine, and none of the flexibility and adaptability of the DME Motronic sytem will be used! There may be drivability problems under changing weather conditions.

Fuel mileage will suffer significantly, and spark plug life will probably suffer, too! The idea kind of reminds me of running a carburetor with a stuck-closed choke ...

If your O2 sensor needs to be replaced, that is what I would recommend!

Does the O2 Sensor not get replaced when you install a cat bypass?

Hi Warren,
I actually wire brushed my sensor and cleaned it with brake cleaner and it made a huge improvement if fluctuating revs is your problem?

The catalytic converter is NOT a part of the DME system design ... many versions of the 3.2 ROW engines never had a catalyst, but <b>ALL had O2 sensors ... because it is an inherent, fundamental part of DME system design!

There is a myth, probably born in the SC days ... that catalysts and O2 sensors wre somehow interrelated in emmisions systems designs, but that is FALSE!!!</b>

As warren says....
But please do try cleaning the sensor before replaceing, take 5 minutes. Imagine all of the soot and crud on there from the exhaust!.
My Cat bypass had a thread for the O2 sensor and as Warren said it IS part of your Bosch ignition system. Without it working properly your system will be out of Whack!
It is just part of over half a dozen sensors the Carrera ECU MUST have working and sending info for the engine to be in tune.
Others are the Cylinder head temp sensor, the air temp sensor, the CO2 sensor (or is it CO?), the air flow sensor, oil temp/presure sensors etc etc
Removing the O2 sensor on a Carerra will give you temp. increased perf. but at a cost.
regards
Ben

I can attest that my 84 Euro did not have an O2 sensor originally, the gray market importer added one, and had to add the wire (the green one) all the way up to the computer (it is spliced into the rubber boot), since none previously existed. I added the O2 sensor heater wire and ground (yellow and black) when I bought it to try to fix some cold running problems (it did nothing, but hey, I hate disconnected wires ;) ).