Spanner size
 

Anyone know the exact size of spanner for removing o2 lambda sensor on the down pipe as tried 19mm not a chance that fitting like .

Think its 22 though I cant remember

I've got a special socket with the side cut out of it to allow for the cable, will try and remember to have a look tonight.

22mm spanner fits but cant undo from the top as spanner hits the turbo haha might try from underneath .

22mm......

I too have one of the fancy Sockets with the slot!

22mm

Mmmmm well the sensor is not budging but on another note not sure if its helped but we know the car needs mapped but un plugged the sensor and its seems to improve it but we see tomorrow when driving to work lol .

probably will need heating to remove if seized, my ones on the R32 were a bit of a pain to get out. Have to be careful the threads don't knacker, probably worth running a tap through to clean it up before putting back in.

Just looked and mines 7/8" so 0.2mm better than yours.

If you unplug the lambda the fuelling will run off the base map which will be close to where it needs to be (14.7 AFR at idle), but probably not quite tight enough control for an MOT.
Failing lambda normally give a duff low reading which cause idle and cruise to run rich at about 12AFR.

Unplugged is fine in this instance, and they don't tend to log a fault unless you force a diagnostic test.

The lambda is only used at idle and cruise (approx less than around 3500rpn and negative boost/vacum).
MAF controlled fuelling is used beyond that point.

Picking up new lambda sensor tomorrow also have some goodies from Ron so i will have a spare just incase .