Originally Posted by themyst
My valve cover gasket leaked in cylinder 6 at 32k miles so anything is possible. Hopefully that's not the issue cause it's extremely time consuming to do that job.
Replaced the suspected bad injector and updated the stock software to the latest BMW version - no improvement. All new seals and decoupler elements on all the injectors I moved around, all coded properly. Also cleaned the MAP sensors, and both had oil all over them.
The only "improvement" so far is that the SES light isn't coming on and it is not shutting down a cylinder due to misfires. This, however, also means that it is not setting a code for misfires, and no amount of driving while misfiring will get it to tell me which cylinder is crapping out on me. The damn misfire monitors are turned down so low on the BMW tuning, and it makes for difficult troubleshooting at best. All the other non-turbos have misfire counters for each start cycle, and it will set codes much easier when transient misfires do occur. Really helps diagnose bent valves on all the older M50/M54/S54s that get an accidental mis-shift that barely nicks the valves, since they misfire lightly on cold start once you bend a few valves. Not so in these damn N54s.
So - next week we agreed to bring the car back and pull the intake for a carbon clean and inspect for excessive oil. I also advised that we will need to check the valve cover and gasket. Testing the PCV system via water manometer will let me know whether the whole cover needs to be replaced or just the gasket. I think there's a lot of oil getting into the intake, and myst is probably onto something here.
E92 335i/6MT Dinan Stage 3 intercooler, oil cooler, intake, flash.
E28 M5, R171 SLK350