Oxygen Sensors
 

hi all,

today while changing the trans filter, i have noticed that my cats don't have oxygen sensors installed (bypassed?) what i can see is there is a bolt installed on each (4pcs) pic attached. my X5 is 2001 4.4i full option with sport package and onwed it for almost 9mos now. is this something to worry about or should i enable them by putting O2 sensors?

thanks in advance.

cheers,
royemaun

???
 

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If you're underneath the car, the sensors are post-cat converters.

These sensors exist to make sure the cat is working correctly. Other then that, they serve no purpose (i.e. doesn't affect performance).

If your OBD is not setting off error codes and check engine lights, I don't think you need to do anything

thanks for the infor Werewolf, i was only surprised by what i've seen because i'm in process of ordering 2 pre-cats o2 sensor from the US.

cheers,

Pre-cat sensors adjust air/fuel ratio, the pre-cat are there to confirm that the cats are actually in existance.

I don't see how you're pre-cats could be completely missing, so I'd check for a wiring harness that has been spliced into w/ something to bypass them. I've only seen them used on the post-cats to bypass a CEL on forced induction applications. I still think there is something else going on here.

the wiring harness are present, would check again if they were spliced to connect with something. is this related to rough idle issue? were cat sensors are missing? as i am experiencing rough idle issue. fyi my engine was overhauled because of a blown piston, changed all the gaskets/seals, valve cover, exhaust gasket but the rough idle issue is still present.

cheers,