[NZE90]

Originally Posted by WheelNut2

I only checked the ESS for oil contamination. I haven't had a look at the cam position sensors at all.

Any suggestions for diagnosing ESS or CPS at all? Is there a specific parameter in ISTA I can use to investigate them? Should I get an oscilloscope, back pin them and check out the wave form? I really don't want to just fire the parts cannon at this problem.

ISTA can do that too.

[WheelNut2]

Update! Finally. This is fixed!

I installed new Vanos adjuster units (along with the updated vanos timing disks to suit the updated adjusters), new eccentric shaft sensor, new valvetronic motor seal, ESS seal, and a new valve cover gasket (wasnt leaking, but needs to be replacing as part of the service).

This thing runs super smooth now! Its noticeably smoother during low speed and low RPM driving.

Now, exactly which part solved the problem? I don't know for sure. I'd suspect it was the Vanos adjusters, but it could have been the ESS or valvetronic gasket. A buddy of mine who is a long time BMW tech had a quick look at the car in the drive way a few weeks ago and thought it sounded like a vacuum leak. There was a bit of oil around the valvetronic motor, so was it leaking vacuum? It didn't release any smoke when I tested it, so I kind of doubt it. The RPM of the car DOES change now when you open the oil filler cap, which didn't happen before. I couldn't see any damage or issues on the Vanos adjusters or ESS, but that doesn't mean that they weren't the issue.