[Nero10578]

My car is a 2010 E90 335i N54 and I bought it used with apparently some kind of upgraded turbos already installed. I have a custom tune by Wedge that with what I can see targets about 16psi for 1/2nd gear and 17-18psi for 3rd/4th/5th/6th gears. Also have an XHP Stage 3 flash on it.

Hardware wise besides the unknown upgraded turbos it has a G-Plus intercooler which keeps IATs just fine, NGK 95706 gapped to 0.022", fresh Eldor coils, VRSF CP, upgraded TMAP sensor, but stock downpipe and exhaust.

I have been getting a pretty consistent misfire whenever I do a WOT pull and I've found out that it only happens if its on 3rd gear or higher and if I upshift at above 6500RPM. The car happily goes to 7000RPM and upshift on 1st and 2nd gears but it just does not like it in 3rd gear or higher and would immediately throw a CEL light along with a code for misfire. I can go through 1st to 5th gear foot to the floor as long as I don't upshift above 6500RPM.

I searched for if anyone has had a similar issue but came out empty handed. Most of what I got was that a misfire at high RPM could be a false alarm from the vibration or something and some people fixed it by changing all the injectors and coils/plugs. Ken from Wedge told me to get new injectors first because yes mine are leaking but the worst bank is on bank 2 which doesn't get any misfires at all, instead the misfires are from bank 1 which doesn't look like it leaks much from the logs.

I tried moving coil packs but the misfire wouldn't follow it, it usually happens to cylinder 1 only and occasionally cylinder 3. Given how it doesn't move with the coils I was thinking maybe the plugs but I guess a broken injectors could cause problems as well? The thing is the injectors that leak more are in the bank 2 and those had cylinders 4/6 pretty dark with soot when I changed the plugs. I want to know what you guys with more knowledge would think about this situation.

Seeing the logs I can't really see anything go wrong either with the LPFP keeping up easily and the HPFP isn't crashing either. The timing corrections were minimal as well and the extreme timing corrections and increased AFR only happened AFTER the misfire when the ECU shut down that cylinder.

[BM3Rrrr]

First you shouldn't be pushing above 6500rpm as the n54's has no more power after that anyways.

If its not following the coils when you move them around its the plugs. You say you have leaking injectors on bank 2 only? Did you let the car sit overnight then pull each plug and inspect them for fuel smell?

[Nero10578]

Originally Posted by BM3Rrrr

First you shouldn't be pushing above 6500rpm as the n54's has no more power after that anyways.

If its not following the coils when you move them around its the plugs. You say you have leaking injectors on bank 2 only? Did you let the car sit overnight then pull each plug and inspect them for fuel smell?

The turbos on my car can keep up to redline. Boost PSI is flat all the way to redline so yea it makes sense for me to rev it out. Might try getting new plugs soon but I think I might as well change injectors too its the most likely culprit i think?

Yes bank 2 is leaking pretty bad in that i can see in logs AFRs won't lean out on throttle lift. Bank 1 leans out but i can see it doesn't lean out perfectly on lower rpm throttle lift either so i probably have some slightly leaking injectors there too. They are index 7 injectors after all which were notorious for issues.

[BM3Rrrr]

Can you post a log?

[Nero10578]

Originally Posted by BM3Rrrr

Can you post a log?

Yea here's a log of 2nd to 5th WOT pull with no misfire shifting just before 6500RPM.

https://datazap.me/u/owenarliawan/ac...og=0&data=3-22

And here's a 2nd to 3rd WOT pull that immediately causes a misfire when I try to upshift at 7000RPM. Error code scanned was misfire on cylinder 1 everytime and no other codes.

https://datazap.me/u/owenarliawan/ac...og=0&data=3-22

[NoGuru]

Look at this video that describes the ring around the injector being loose and causing misfires up high.

[Nero10578]

Originally Posted by NoGuru

Look at this video that describes the ring around the injector being loose and causing misfires up high.

Interesting...it wouldn't cause AFRs to not lean out though would it? So maybe I'll check it when I get new injectors installed.

[S`ebu]

Hi! Did you get fixed this problem?

I have had similar problems with my N54. It doesn't matter if I WOT to 6500 rpm or just like 50% throttle accelerate to 6500 rpm I always get misfire. Usually it's cyl no. 5 but sometimes also 1,2 etc and few times also got all cyl....
I have BL coils coded correctly w/ MHD. Plugs gapped to 0.025". I have changed the coil places and doesn't matter. One thing noticed when changing the coils places that cyl 5 coil was way more hotter than other after the misfire :/ Could it be the plug gap is too big or the plug is already broken after 2000 km?

[NoGuru]

Originally Posted by S`ebu

Hi! Did you get fixed this problem?

I have had similar problems with my N54. It doesn't matter if I WOT to 6500 rpm or just like 50% throttle accelerate to 6500 rpm I always get misfire. Usually it's cyl no. 5 but sometimes also 1,2 etc and few times also got all cyl....
I have BL coils coded correctly w/ MHD. Plugs gapped to 0.025". I have changed the coil places and doesn't matter. One thing noticed when changing the coils places that cyl 5 coil was way more hotter than other after the misfire :/ Could it be the plug gap is too big or the plug is already broken after 2000 km?

You should start a new thread. List your mods and what you have checked.

[gkuba911]

Anything new in this two cars? I have same problem and looking for solution because i did chceck everything twice...

https://datazap.me/u/jakub-gracz/4-b...og=0&data=3-15

[jayconemst]

Originally Posted by Nero10578

My car is a 2010 E90 335i N54 and I bought it used with apparently some kind of upgraded turbos already installed. I have a custom tune by Wedge that with what I can see targets about 16psi for 1/2nd gear and 17-18psi for 3rd/4th/5th/6th gears. Also have an XHP Stage 3 flash on it.

Hardware wise besides the unknown upgraded turbos it has a G-Plus intercooler which keeps IATs just fine, NGK 95706 gapped to 0.022", fresh Eldor coils, VRSF CP, upgraded TMAP sensor, but stock downpipe and exhaust.

I have been getting a pretty consistent misfire whenever I do a WOT pull and I've found out that it only happens if its on 3rd gear or higher and if I upshift at above 6500RPM. The car happily goes to 7000RPM and upshift on 1st and 2nd gears but it just does not like it in 3rd gear or higher and would immediately throw a CEL light along with a code for misfire. I can go through 1st to 5th gear foot to the floor as long as I don't upshift above 6500RPM.

I searched for if anyone has had a similar issue but came out empty handed. Most of what I got was that a misfire at high RPM could be a false alarm from the vibration or something and some people fixed it by changing all the injectors and coils/plugs. Ken from Wedge told me to get new injectors first because yes mine are leaking but the worst bank is on bank 2 which doesn't get any misfires at all, instead the misfires are from bank 1 which doesn't look like it leaks much from the logs.

I tried moving coil packs but the misfire wouldn't follow it, it usually happens to cylinder 1 only and occasionally cylinder 3. Given how it doesn't move with the coils I was thinking maybe the plugs but I guess a broken injectors could cause problems as well? The thing is the injectors that leak more are in the bank 2 and those had cylinders 4/6 pretty dark with soot when I changed the plugs. I want to know what you guys with more knowledge would think about this situation.

Seeing the logs I can't really see anything go wrong either with the LPFP keeping up easily and the HPFP isn't crashing either. The timing corrections were minimal as well and the extreme timing corrections and increased AFR only happened AFTER the misfire when the ECU shut down that cylinder.

I was wondering if anyone has an update or has fixed this problem, started having cyl 5 misfires at 3k or higher rpm 3rd gear, did coils, sparks, and injectors nothing has fixed it, it made the misfire only happen at higher rpms 5,500 or higher havent tested it much, if anyone has any ideas, or knows what happened with the original car it would be a lot of help.

[asterfern]

How's the health of your battery? I know this sounds odd of a question, but I remember reading somewhere years ago that if your battery is low that it could be causing issues like this. I could be completely off here, but regardless curious about your battery health / date stamp.

[jayconemst]

its fine, its charging good and haven't had any problems with the bat, its less than 3 years old

[AidanN335iDCT]

did this ever get fixed? im having the exact same issue!

[NoGuru]

Originally Posted by AidanN335iDCT

did this ever get fixed? im having the exact same issue!

DCT! So I fixed my high RPM issue by changing the flywheel to an M4 flywheel on my DCT.

[AidanN335iDCT]

Originally Posted by NoGuru

DCT! So I fixed my high RPM issue by changing the flywheel to an M4 flywheel on my DCT.

oh poo, mine is a DCT too so wondering if this could be it. changing injectors tomorrow and hoping that fixes it. I thought if it was a flywheel issue it could be cylinder 5 or 6?