[Knob]

So my stock E90 335xi N54 with 80.000km (50.000miles) has combustion misfires at around 2000-3000rpms on cylinder 5, fi I accellerate lightly at 2k rpms the car begins to stutter, if I keep going it cuts off cyl. 5 resulting in "29D1 - DME: Combustion misfires, cylinder 5". But it works fine at around 3300rpm and more, here´s what I already did:

- 6x new Spark plugs
- 6x new ignition coils
- 6x new injectors index 12 (coded as well)
- Compression test, on all cylinders fine
- Replaced 6 mosfets on DME MSD80
- 4 new o2 sensors
- Swapped coils. spark plugs and injectors from cylinder 5 to other cylinders

Cold start is fine, the car starts great, also you can cruise along and WOT above 3000rpms..

I haven´t checked the intake valves yet, that´s what coming next, but before I continue and order more parts, I wanted to ask you, I already searched the forums...

I´m tinking it may still be the DME, what do you think?

[Saif2018]

Originally Posted by Knob

So my stock E90 335xi N54 with 80.000km (50.000miles) has combustion misfires at around 2000-3000rpms on cylinder 5, fi I accellerate lightly at 2k rpms the car begins to stutter, if I keep going it cuts off cyl. 5 resulting in "29D1 - DME: Combustion misfires, cylinder 5". But it works fine at around 3300rpm and more, here´s what I already did:

- 6x new Spark plugs
- 6x new ignition coils
- 6x new injectors index 12 (coded as well)
- Compression test, on all cylinders fine
- Replaced 6 mosfets on DME MSD80
- 4 new o2 sensors

Cold start is fine, the car starts great, also you can cruise along and WOT above 3000rpms..

I haven´t checked the intake valves yet, that´s what coming next, but before I continue and order more parts, I wanted to ask you, I already searched the forums...

I´m tinking it may still be the DME, what do you think?

It's possible you need a walnut blast,

Plugs are Bosch OEM ones?

Swap plugs and coils from cylinder 5 to another cylinder and see if misfire follows,

[Knob]

I already swapped them to another cylinder, including injectors. Plugs are Delphi, DEL-GN10571, I´m using the Delphis ones on another E92 N54 and was using them in another E90 N54, but I also tested OEM plugs, NGK, and other, same result.

This is not much throttle:
https://www.dropbox.com/s/lc6e1dkh5r..._7683.MOV?dl=0
https://www.dropbox.com/s/40zcg3gtpa..._7684.MOV?dl=0

This is full throttle from still standing:
https://www.dropbox.com/s/n2xo3m01i5..._7689.MOV?dl=0

[Saif2018]

Originally Posted by Knob

I already swapped them to another cylinder, including injectors. Plugs are Delphi, DEL-GN10571, I´m using the Delphis ones on another E92 N54 and was using them in another E90 N54, but I also tested OEM plugs, NGK, and other, same result.

This is not much throttle:
https://www.dropbox.com/s/lc6e1dkh5r..._7683.MOV?dl=0
https://www.dropbox.com/s/40zcg3gtpa..._7684.MOV?dl=0

This is full throttle from still standing:
https://www.dropbox.com/s/n2xo3m01i5..._7689.MOV?dl=0

Did the misfire follow when you swapped?

[Knob]

No, it always stays on cylinder 5

[ab987]

Originally Posted by Knob

No, it always stays on cylinder 5

How do rough running values in INPA look? What compression numbers were you seeing? I don't think carbon at 50k would be bad enough to cause misfires, mine sure didn't at 90k.

My only other thought is a fueling issue. Can you upload a log for us to check out?

[Knob]

Btw, the car was standing around a long time and had an accident in the USA, a few years ago it was imported to Germany, last year I started the repairs and now its officially registered here. In the meantime I drove 1800/2000 miles, so the "bad" fuel should be completely gone, a few weeks ago I replaced all the stuff mentioned in the first post.

I can´t remember the compression numbers, my shop did this, but I´ll ask again.

Couldn´t see anything wrong in INPA. This is light acceleration from 2000 rpms, then cylinder 5 shuts of at 2800 rpms or so, but I kept going, because somebody said I should generate a log like that:
https://datazap.me/u/frederik/2k-rpm-mkl-bis-5k-rpm

This in an older log, at the end I provoked the misfires (with old spark plugs):
https://datazap.me/u/frederik/log-16...og=0&data=3-20

But only a fuel issue on cylinder 5?

[Saif2018]

Originally Posted by Knob

No, it always stays on cylinder 5

You installed New OEM Bosch 3 pronged plugs and swapped them and checked right?

[Saif2018]

Originally Posted by Knob

Btw, the car was standing around a long time and had an accident in the USA, a few years ago it was imported to Germany, last year I started the repairs and now its officially registered here. In the meantime I drove 1800/2000 miles, so the "bad" fuel should be completely gone, a few weeks ago I replaced all the stuff mentioned in the first post.

I can´t remember the compression numbers, my shop did this, but I´ll ask again.

Couldn´t see anything wrong in INPA. This is light acceleration from 2000 rpms, then cylinder 5 shuts of at 2800 rpms or so, but I kept going, because somebody said I should generate a log like that:
https://datazap.me/u/frederik/2k-rpm-mkl-bis-5k-rpm

This in an older log, at the end I provoked the misfires (with old spark plugs):
https://datazap.me/u/frederik/log-16...og=0&data=3-20

But only a fuel issue on cylinder 5?

LPFP and HPFP, LTFT all need to be logged.

[Knob]

I can´t do new logs right now, the car is standing in my shop

[ab987]

Thanks for the logs. Here's my theory: cylinder 5's injector is dumping fuel, which is probably causing your DME to lean out 4 and 6, causing some of those corrections you are seeing. Rail pressure is probably pretty low given the intense fuel flow, causing bank 1 to lean out too. Check the connector for that injector, my only worldly idea would be that the connector or wiring is damaged and causing the injector to act wild under load. I've never seen something like this so it could be way off, but it's good to at least check the easy stuff without throwing money at the car.

[Knob]

Here in the forums a few similar cases, but in most threads there were no answers in the end, or no on told us how it ended. Since I couldn´t figure it out, I gave it to my workshop, but I can get there anytime and check stuff on my own. With this low mileage it would be a shame if I can´t get it running fine.

Sounds plausibel ab987 , in my opinion all left is wiring, connector, still DME (not still DRE ), high and low pressure fuel pump and intake valves, or am I wrong?

Also I got new vaico solenoid valves here, cause somebody told me it COULD theoretically cause something like that, but I´m trying to chase every good hint..

[Wolf 335]

I’m not sure if this has any merit but it may be worth checking if the injector port is suffering from oval port issue.

Good luck with this and keep us posted with your remedy.

[Knob]

Never heared of that tbh, I also talked to many n54 drivers here in Germany, none of them had that problem. I don´t hope so (even though it seems fixable?), but we will see

[Dave92N54]

Originally Posted by Knob

Never heared of that tbh, I also talked to many n54 drivers here in Germany, none of them had that problem. I don´t hope so (even though it seems fixable?), but we will see

This is probably due to the fact that you all did not seem to experience injector failure on the scale we did here in the states, which has led to plenty of people improperly removing injectors and ovaling out their ports in the head.

[Knob]

Indeed mate, here in the forums are a plenty of threads over that, I hope its not that, but I will see and give you an update

[El-daybed]

Originally Posted by Knob

Indeed mate, here in the forums are a plenty of threads over that, I hope its not that, but I will see and give you an update

Did you ever figure out your issue, im having the same issue with cylinder 4 but only on cold starts

[Knob]

Nah, not yet. What did you change so far? I had this too, after replacing the injectors its completely gone.

[El-daybed]

Originally Posted by Knob

Nah, not yet. What did you change so far? I had this too, after replacing the injectors its completely gone.

I replaced plugs coils and injectors still there, i guess im gonna try valve cover and see if its a vacuum leak or lean issue

[Knob]

Took longer, but it drives awesome again. I replaced a few vacuum lines, they weren´t too bad, but when I was there, I did that. My intake valves looked surprisingly good, especially on cylinder 5. But I also did replace the low pressure sensor at the high pressure pump, which was more like "well, let´s see if it makes a difference". And after that I did not had a single misfire

[Saif2018]

Originally Posted by Knob

Took longer, but it drives awesome again. I replaced a few vacuum lines, they weren´t too bad, but when I was there, I did that. My intake valves looked surprisingly good, especially on cylinder 5. But I also did replace the low pressure sensor at the high pressure pump, which was more like "well, let´s see if it makes a difference". And after that I did not had a single misfire

That's good, sounds like you had a fuel pressure issue caused by a faulty sensor. How long has it been misfire free?

Did you manage to log HPFP, LPFP and STFT and do a 3rd gear log?

[Knob]

Didn´t log anything yet, since the car runs pretty smooth. Before that I couldn´t barely accelerate without a CEL, that works without problems again. One thing I didn´t mention was, sometimes I got an error like "misfire at low fuel", where the fuel was really low, but I´ve read that is quite common and nothing to worry about..