335xi n54 misfire
 

I have seen many cases of hostility when it comes to posting something or questions that have already been covered, so please bare with me and understand I have researched and dig around any and every forum out there. So if you can’t help please avoid the hateful commentary.

Now that’s out of the way let’s get started.
Issue 29D1 cyl5 misfire, only code being thrown except secondary o2 sensors due to cd’s.

Mod list:
Jb4 gen 5
DCI
Bms cp
Vrsf ******* **
Custom exhaust(secondary *** delete, resonator delete, vibrant resonators installed with x pipe, stock muffler)
Everything else should be miscellaneous

Car has 100k miles and was very neglected.
New coils: FCP euro, ELD-R3516S00100
New plugs: bms, ngk 5992
New vanos selonoids
Cyl3 plug showed small traces of oil on threads (no issues with three though)
Plugs were gapped at .022

Even map 4 this misfire will rise but it is absolutely more reluctant on map 2 or 5. Daily driving causes no issues car runs fine, crank time in 30 degree weather is 1 1/2 seconds(idk if normal). So what’s happening is 2nd threw 4th gear if you are below that 4K range and try any more than 25-50% throttle it imidiately misfires for 29d1 until code is cleared or car restarted. If you work your way into a higher rpm tang let’s say 5k or greater the car runs fine the best I can tell. Any help on this will be greatly appreciated.

put up a log.

Jb4 bt connect is on its way

Sticky/bad injector? To start trouble shooting move your plugs and coils on #5 to another cylinder and see if the misfire moves with it.

FYI the JB4 BT connect app is awesome!!

Jam, Cyl 5 was misfiring before/after new plugs and coils

Ok so quick update, hopefully you can help or know someone. bt connect by bms will be here in a few days. Randomly got a cyl 4 misfire with my 5 on the way home I popped the engine cover after I found out you can get the revision of the injector by the code etc. well bank 1 has cyl1-index11, cyl2-index12, cyl3-index11. But bank to has cyl4-? Cyl5-?, cyl6-index12. Injector 4 and 5 both appear to have like something that almost looks like tape covering the numbers that give you the index of the inj. Maybe meaning they could be factory?? Like a index 05😂 maybe why the car is running like a three legged mule (couldn’t get good picture it was late and dark)

I had the same issue where I had Oil in Cyl6, and enough to seep through the threads into Cyl6. This alone wasn't causing my issues though. The Oil leaking was from a valve gasket going bad.

I started to have misfires in Cyl3 even on stock maps. I already swapped out all plugs with new. All new coils were installed about a year ago from bavauto. I was now down to either the injector or the LPFP (HPFP was also replaced a few years ago). I was having very long cold starts, and the last morning where it completely died and didn't start was the first night it froze in my area. That particular morning the entire car was shaking and shuddering, I was throwing a ton of white smoke out the back and tons of unburnt fuel coming out the exhaust, and misfires in ALL cylinders.

I started to compare all the injectors values to what was in the ECU. After closer inspection I noticed that injector 3 was not the same as all the others. I bought the car used with 21k miles, and someone before me already had one injector replaced. But the bad thing was the injector 3 values did not match what was in the ECU!!! They were off considerably. The index for all the injectors were in the same class with 7 or 9 (class being index version 1-9, or 10+), but the injector values were not even close.

Funny enough I had a spare injector that matched the index, but I only had one. Yes, you are suppose to replace them in groups of three, front bank or back bank, but I was desperate. Luckily the fuel rail is individual per injector. I swapped injector 3, waited for it to warm up a bit, started the car, and to my surprise it started and ran for 5-10 minutes with not a single hiccup! On closer inspection the old injector 3 was stuck open, and just dumping fuel into cyl3.

However, the next morning everything died again. Misfires in every cyl. Come to find out, my LPFP was dying a horrible death. Got that replaced last week, and the car is back to running 400-450bhp, and feels as good as when I first got the jb4 on it. Also checked to ensure the original white smoke wasn't a leak of coolant or other issues. Everything checked out, and car is running clean and strong again.

Did the wrong injector values potentially cause the premature death of injector 3? Or the premature death of the LPFP? Who knows. But I double checked EVERY injector and they are all accurate now.

Sorry for the long story, but just wanted to explain the process of what happened to me.