Right, here goes. irrespective of whether the car is eventually repaired, I would like to know what is going on. So here are some traces. I have also attempted to record the emissions at tailpipe but I didnt make such a good job of those (only one pair of hands)

Cold Idle.




corresponding emissions

CO 0.56%
CO2 14.48
HC
o2 0.9
NOX 125
Lambda 1.023



A bit later



Corresponding emissions

HC 148
CO 0.37
co2 14.48
o2 0.8
NOX 79
Lambda 1.02


This is where it starts to get wierd.



Corresponding emissions

HC 308
CO 0.461
co2 14.15
o2 1.08
NOX 73
Lambda 1.024


Later



Emissions

HC 424
co 0.47
co2 14.06
o2 1.20
NOX 76
lambda 1.027

And eventually it does this...




HC 424
o2 1.75
co2 13.82
co 0.363
NOX 80
lambda 1.06

The transition from switching to constant is quite sudden but happened just as the scan went to a new page

These were all at idle.

At speed, once hot, I got this





the red trace corresponds to throttle sensor.

I amm affraid that at this point I wasnt so good at taking emissions readings

when you release the throttle it does this.






Short term fuel trim 3.06%
Long term trim -0.8%

Live data states operation in closed loop!


So what is happening here and why???