[mehr]

Hey guys,

I'm having some trouble with my car and would really appreciate some help in trying to figure it out.

Background: Car is a 07 N54 with JB4 G5 ISO (latest firmware), DCI and Chargepipe. 150k kms. I run it on Map 1.

Car has a rough cold start idle, with no misfire codes. Idle is fine once warm.
When warm and cruising at aroudn 3k RPM and then applying slight gas, there is sometimes a 'bucking' or 'surging' hesitation, and the car then continues on.

During WOT runs the car will abruptly jerk in the high RPMs (~6k) and then continue on.

Pulling the codes reveal a shadow code of 2FDB (always there regardless of city driving or WOT).
During the WOT runs, the car throws a superknock code. The cylinder varies, but cylinder 1 (30ED) and cylinder 4 (30F0) seem to pop up most often. The other cylinders, 3, 5, and 6 codes appear as well. For some reason cylinder 2 never does...

What i've done (all within the last 5k kms):
- new spark plugs (OEM Bosch) and then replaced again with 1 step colder NGK 95770
- replaced all ignition coils with Delphi coils
- walnut blast
- valve cover & valve cover gasket
- oil change (castrol 5w-30 european)
- always use 91 shell V-Power (used PetroCan 94 before but heard it has ethanol)
- ran injector cleaner
- adaptation reset

After replacing the plugs and running injector cleaner, it seems to help for a short period of time, but the rough idle comes back.

I suspect my injectors may be giving out, considering they are index 3 and 9 (BMW only replaced 3 of em at 60k kms). It could explain the blackness on the plugs after pulling them after a night of sitting.

Using the JB4 logging app, I have yet to see my HPFP dip below 5 and my LPFP dip below 60psi, but maybe these are problematic as well?
HPFP last replaced at 60k kms by BMW. I don't have any other HPFP symptoms like long crank, etc.
I've also read some posts suggesting it's the O2 sensors. Mine have never been replaced but I have no codes for them.
I'm considering the JB4 BEF as well, not sure if it will help with these issues.

The car otherwise behaves absolutely fine, pulls strong and hard, no smoking, no leaks, etc.

Anyone have any experience or guidance with these codes?

Thanks!
-M

EDIT: Noticed in my JB4 logs that my Ign1 makes sharp corrections of over 3 degrees. It seems to be worse compared to logs from a few months prior. Further suspecting injectors.

[torrque]

Pull out that JB4, make sure you run fine stock first. When fixed, put it back in.
I would put my money on injectors first, and then LPFP and/or LPFP sensor.

You can run the car with O2 sensors completely disconnected, apart from check engine light you won't feel anything.

[mehr]

Thanks for the suggestion!

I heard about disconnecting the after-cat O2 sensors, but don't the pre-cat O2 sensors affect AFRs?