Lambda Sensors

[Paul H Johnson]

Hi all, a few quick questions for you !! My 1997 2.8 has just failed its MOT on emissions. On inspection by the tester, he found that the wires from the post cat lambda sensor had been cut off, leaving the sensor itself as a blanking plug !!! When we investigated further, there was very little evidence of the route of the cable or where it connected back to the on-board computer. The pre cat sensor & its connection are in place & are easily visible. My questions are: Does my Z3 normally have 2 lambda sensors & if so, what's the cable route & where does it connect ??? I hope someone can help !!! Thanks in anticipation to any of you that knows the answer !!!
Rgds
Paul J

 

[jonco]

I think only one but need a 2.8 owner to confirm. On the M44 1.9 there is only one - the double sensor was for US market emissions at that time.

Realoem only shows one for the 2.8 https://www.realoem.com/bmw/enUS/showparts?id=CJ32-EUR-04-1997-Z3-BMW-Z3_28&diagId=18_0252

 

[colb]

oem parts site shows pre cat and post cat sensors here https://www.realoem.com/bmw/enUS/showparts?id=CJ32-EUR-06-1997-Z3-BMW-Z3_28&diagId=18_0252
If you look at the left side of the cam cover you should find the connections clipped along the edge of the cover. If your post cat sensor has been cut you should find the empty connector tucked upn along the cam cover with the pre cat connector.

 

[jonco]

oem parts site shows pre cat and post cat sensors here ....

The post cat (item 17) is faded out and not included in parts listing. I thought this meant not installed on this model.

 

[colb]

Your right, shaded out so not fitted to yours, can only think your exhaust is not the original otherwise I would have expected a blanking plug, they wouldn't have put a sensor in there to act as a blanking plug.