N62 issues after timing chain replacement

[raksike]

I have arranged the timing chain replacement on my X5 2004 which has the N62 4.4 engine.
I have ran the car previously for 2 years without the camshaft sensor unplugged, since this way it did run without any misfires or any rough idle. Probably the car has the worn Internediate levers issue.
Now after replacing the timing chains +many other things such as valve stem seals etc. the engine is running now rough at cold starts, the cam sensor is unplugged and after some time of driving I get in addition to the cam sensor error also the fault code P3019 which give the definition O2S Sensor Lambda Controller Value Above Threshold due to Open Pumping Current Circuit (Bank 2 Sensor 1)

When the engine warmes then it runs ok. Any suggestion where to start from now? Before the engine teardown there was no similar fault code, only the DTC for related to the unplugged cam sensor.

[andrewwynn]

Rough idle when cold on n62 usually has to do with Valvetronic calibration which often is related to eccentric shaft or intermediate levers problem. There was a recall so look if your engine was made during the recall years. Probably too late to act on but at least may help to determine what's what.

Finding the right tool to adjust the minimum lift for Valvetronic may resolve the problem.

[raksike]

As I mentioned the cam sensor was off for two years and I did not got any errors or misfires. Based on my understandin when the cam sensor is unplugged the valve lift is set to 6mm. There is for sure an issue with the intermediate levers and eccentric shaft, but as I mentioned it ran before the timing chain was replaced without issues. My main question is what can cause the DTC 3019, it was not there before and now it is, I doubt this is related to the valvetronic, because it would have been there also before the timing chain replacement.

Could it be bad O2 sensor?

[andrewwynn]

It definitely didn't "run without issue" with CPS disconnected. The engine can't run properly without knowing where the cam is. I'm curious exactly what self-crippling limp mode is engaged in this case.