Bloody O2 sensors again!!!! Should have done a recall!!

[GuidoK]

Could be the sensors, but I don't think it's the heater circuit in this instance. (no code)
And I think z4m precat o2 sensors are considerably more at the dealer than £90/pc. I think almost double at bmw's premium prices... It's a lsu 4.2 afaik so not narrowband (at least that's what I think, just speculating)
So pretty expensive for just an attempt. You can get an lsu4.2 much cheaper online (so non specific bmw), but I don't know if the z4m has the standard bosch connector.

 

[Beedub]

I've got some off the car if anyone wants pics of the connecters etc.

 

[TomK]

I believe the connector is specific to the Z, it's square and it's a 5 rather than 4 cable arrangement used in the circular connector by the e46m3.
Don't really want to swap them but struggling to come up with anything else that could explain the symptons.

 

[Izice]

Out come update :

Got z4mr back today after paying £600 for x2 O2 lamda sensors.

Bank 1 pre cat and Bank 2 pre cat both changed.....apparently 6 hrs of work too.

Asked what they had done...puzzled look by salesman/service manager....did they check heater circuit? ......or do air test on exhaust system?....more puzzled looks followed by the " techs followed their diagnostics"....mmm.

Because previous O2 sensors were covered by AU warranty they are not covered by the BMW parts guarantee for 2 yrs. Also charged me £4.12 for a clip that holds the OBD11 port socket in place...will have to fit myself though.

They also said if they throw some faults O2 sensor faults they would have to change the ECU.... I questioned this as it has never shown as a fault code and suggested it may be something else. Also quizzed him on the fault diagnosis process and asked whether it was a blinkered approach and perhaps they should look at other potential reasons the faults are occurring instead of just plugging a code reader in and fixing what it says.

Anyways fingers crossed its fixed and a can start enjoying the beast now after what has been an expensive 2 months which has cost £2200 so far (disc n pads all round/ rear tyres/ throttle response sensor/hand brake shoe pads/ x1 additionalO2 sensor and x3 points on my licence).

Thanks for all the replies and advice