[janpa7]

Hi,

This is my first time posting here. I have a misfiring issue with my 2008 335xi N54 touring which has 154,000 km, fully stock. I've read a lot of posts here, but I couldn't find a clear answer to my issue.

BACKGROUND:
My car was running fine, with an intermittent and very light misfire for 2-3 years.

In February 2023, I had my AT gearbox repaired and cylinder 1 injector replaced with index 12, while all other injectors on index 8. The above misfire almost completely went away and my car worked well.

In May 2023, I purchased MHD tuning and happily flashed my DME to stage 1. I was thrilled and excited, as I only recently knew that the N54 engine was so famous and so powerful. The car drove totally fine for 3 days on MHD stage 1 tune. However, on the 3rd day, when I fully stepped on the accelerator, I felt a sudden and unusual loss of power, and a rough rpm and unusual noise coming from the engine, later my car just died and I couldn't start it.

Basically, my MSD80 DME fried because of the stage 1 tune. Therefore, I replaced the Mosfets in July 2023. However, 20mn after driving, as soon as I went full throttle, the same issue happened: a sudden loss of power, rough idle and car died soon after.

I then decided to upgrade to MSD81.

THE ISSUE:
After the upgrade, my car finally started, but the idle was very rough and I had no control on the accelerator. After resetting throttle adaptation, the idle was still rough but more stable and I had some control on the accelerator.

I then proceeded with replacing the ignition coil with OEM Eldor coils. My car was running smoothly and nicely at the first start, however, as my engine started to warm just slightly above 70° Celsius (158°F), the idle started to become rough again, not as wild though and I still had control on the accelerator. However, I was happy as this was an improvement overall.

I then proceeded with changing the spark plugs with OE Bosch. But, the symptom was the same, my car started to idle roughly with an unusual noise and it would still feel rough when accelerating.

Here are my current error codes:
- DME active codes -
29CC - DME: Combustion misfires, several cylinders.
29CE - DME: Combustion misfires, cylinder 2.
29CF - DME: Combustion misfires, cylinder 3.
29D0 - DME: Combustion misfires, cylinder 4.
29D1 - DME: Combustion misfires, cylinder 5.
29E0 - DME: Mixture control.
29E1 - DME: Mixture control 2.

Yesterday, before clearing the codes, I had these codes below (in addition to the above ones):

2A2C - DME: Mixture control 2.
2CFB - DME: Throttle-valve adaptation value.
2D09 - DME: THROTTLE.

- DME shadow (inactive) codes -
2FDB Fuel high pressure nach Freigabe der Einspritzung

MY ANALYSIS:
Before my DME fried with stage 1, my car was running fine. And, I have almost not been driving my car since then (for 2-3 months), as it was grounded and impossible to start the whole time.
So, I think it is very unlikely that I now have injector number 2-3-4-5 misfiring all of a sudden. It just cannot be. 4 Injectors don't go bad simultaneously because of DME failure as far as I know.

Coils and spark plugs are new, so no issues there.

I read here that 29E0 and 29E1 combined indicate a tuning issue. https://bmwtuning.co/bmw-n54-common-...s%20at%20fault.
What exactly is a tuning issue?

After googling code 29E1 and 29E0, it seems like some people had issues with the O2 sensors. Some other people had clogged Downpipe with these codes. But, what is troubling me is that they had slightly different error codes than me, so I cannot be sure I have a clogged downpipe or issue with O2 sensors.

Also, as I said above, when my MSD80 mosfets were repaired, I had no issues or whatsoever with misfiring, DP, or even O2 sensors codes. Even before my MSD80 fried in May, I also didn't have any issues or codes. Maybe a very slight misfire time to time at best.

When the DME was fried, we tried to start my car many, many times and during that process there was black smoke coming out of the exhaust, as we were trying. So, I can imagine that it is possible some parts got clogged because of that black smoke, like injector 2-3-4-5 or maybe even the downpipe got clogged, because many people tried to restart my car (me, my garage, the towing company, etc.), but I really cannot be sure if some smoke could really cause such a damage.

I don't think that having index 12 on cylinder 1 and index 8 on all other cylinders caused my current issue as it was totally fine before I upgraded to MSD81 and, it would be very unlikely, again, that my injectors went bad at the same time as my DME.

So, what do you guys think? I am really clueless. I would like to have some sort of certainty before throwing a lot of money... I was thinking to change the injectors with index 12 next, or changing the O2 sensors...

I read here https://www.e90post.com/forums/showt...php?p=22552723 that this person was able to test whether the issue came from the O2 sensors/pre cat downpipe, by disconnecting the O2 sensors and starting the engine... But, I don't know exactly which sensor should I disconnect or remove in order to safely test my car... I am scared to damage my car further.

I heard it could also be the HPFP, but I am not familiar at all with the error codes associated with it and why would my cylinder 2-3-4-5 would misfire in that case.

Thank you guys for your help!

[Mustafa.e92]

Throttle adaptation will usually do that their is another procedure you can follow after a reset. YouTube it. Could be a hpfp. I would reset all codes and log a cold start aswell as a wot pull with mhd. Log will give you a lot more info on what’s going on

[janpa7]

After doing some more research, I am leaning towards bad O2 sensors.

Firstly, because O2 sensors can go bad due to contamination from oil ash. That is my case, since we tried to restart the car many times, and in this process, I could see a lot of black smoke coming out of the exhaust, which could have contaminated O2 sensors.
https://www.google.com/search?q=why+...hrome&ie=UTF-8

Second, I found this video from vehicular DIY

I basically have the exact same symptoms and same error codes. The only difference is that I have both bank 1 and bank 2 issues. My 6 spark plugs were pretty much all black as in the video.

What do you guys think? Am I on the right track?
I am going to check if the O2 sensors are plugged correctly, and then order new ones

[lowrydr310]

There's really nothing you posted to suggest bad O2 sensors, they won't cause misfires like that on numerous cylinders. Also burning oil would be white smoke; black smoke is from a rich fuel mixture. Your cylinders could have been getting flooded with fuel from all the attempted starting causing that, and it's unlikely to contaminate an oxygen sensor. Short term smoke isn't going to clog a catalytic converter either.

Do what Mustafa said and clear all codes and start logging with MHD. This sounds like a bad high pressure fuel pump, but data logs will help better understand what's going on.

[janpa7]

Hi everyone,

So I did a datalog https://datazap.me/u/janpatout/220823?log=0&data=3-25

Strangely, this is the first time I got this code today, while I was data logging:

- DME active codes -
29D0 - DME: Combustion misfires, cylinder 4.
30FF - DME: Turbocharger, charge-air pressure too low.

It’s also the first time I pushed to around 3-4 thousand rpm.

When I drive, I hear a slight howling sound from around 2k rpm.
I remember hearing that howling sound when I did the mhd stage 1 tune before upgrading to MSD81, 3 months ago, but at that time I didn’t have issues.

I have no idea how to read datalog, what do you guys think?

[janpa7]

When STFT 2% and LTFT 2% collapse to 0, that’s when I got engine check light.

And at the very end of the data log, I got limp mode.

Until I got the engine check light, the car felt normal, no vibration. Vibration started after engine check light.

Any ideas what it could be?
I surely cannot have several catastrophic failures at the same time such as injectors, turbo, HPFP… my car was running fine up until my dme fried due to stage 1 mhd tune.

By the way, I currently didn’t flash my upgraded MSD81 DME with MHD.

[janpa7]

Originally Posted by Mustafa.e92

Throttle adaptation will usually do that their is another procedure you can follow after a reset. YouTube it. Could be a hpfp. I would reset all codes and log a cold start aswell as a wot pull with mhd. Log will give you a lot more info on what’s going on

Hi, thank you for your answer. I have done data log, see above.

Do you mean throttle adaptation reset will cause misfire/mixture control errors? What other procedure should I do? I have tried to google it many times, but I couldn't find anything. Could you specify please?

Thank you very much!

[Mustafa.e92]

do another log that one is all over the place. Connect with mhd and begin logging before turning the car on for a cold start and stay connected for a minute until the idles sets down. 2nd log. Get on some open road in 2nd or 3rd gear around 2k rpm’s. Start recording a log and floor it until you’ve gone through the rpm’s than end the log. Upload both

[Mustafa.e92]

from a quick glance at the log you posted the afrs look terrible car seems to be running very lean. Check for vacuum leaks aswell

[janpa7]

Originally Posted by Mustafa.e92

do another log that one is all over the place. Connect with mhd and begin logging before turning the car on for a cold start and stay connected for a minute until the idles sets down. 2nd log. Get on some open road in 2nd or 3rd gear around 2k rpm’s. Start recording a log and floor it until you’ve gone through the rpm’s than end the log. Upload both

Ok, I will do a proper cold start datalog.
But, I am scared to do a full throttle with an very shaky and rough engine, in limp mode... I mean, isn't it dangerous for the engine? It's obviously not running well at all.

[Mustafa.e92]

okay no need to go wide open but have one continuous increase of the rpm’s in the same gear. Give it as much as it feels safe to. We want to clearly catch it in the log when it misfires or values go out of parameters

[janpa7]

Originally Posted by Mustafa.e92

from a quick glance at the log you posted the afrs look terrible car seems to be running very lean. Check for vacuum leaks aswell

Yes it’s very lean, but what about LTFT and STFT going to absolute zero and staying there while I’m still driving? It’s not even moving, just staying at zero during the second half of my drive… I have googled it and found nothing…

[janpa7]

Originally Posted by Mustafa.e92

okay no need to go wide open but have one continuous increase of the rpm’s in the same gear. Give it as much as it feels safe to. We want to clearly catch it in the log when it misfires or values go out of parameters

Hi,

So, I have done a cold start log, and gave it a gas up 3000pm, as I didn't feel it was appropriate above that. https://datazap.me/u/janpatout/23082...18-19-25-27-28

I found an invoice from BMW dealership, 2 years ago (or 20,000km ago) they changed the following parts: Thermostat, water pump, vanos solenoid, camshaft sensor, battery, 2 turbo pipes on admission and all lines between these parts and DME were controlled.

In addition, I post some pictures of all the leaks I have found after visual inspection. It seems the thermostat (and maybe oil filter gasket), charge pipe and another part which I am not familiar with are leaking. See below.

Charge pipe/connector leak


Weird wiring done by my garage, the lines may be constricted by the plastic?


Is that the steering liquid leaking?

Lines constricted?

This is below the termostat, you can see that it leaked oil


Please help me, I am still thinking to replace the O2 sensors and after today's inspection I am thinking to change the charge pipe to aluminum or only the connector (if only that is leaking), I want to upgrade the thermostat to mosselman (or change the seal/tube if only that is leaking), and later I want to change the pulleys and serpentine belt (as the oil clearly leaked from the thermostat to the belt below).

Do you guys think the leak in the charge pipe/connector is causing my issue?

Thank you very much!

[Mustafa.e92]

No I meant 2 separate logs lol. cold start dossnt look to bad trims are maxed though it’s trying to add lots of fuel. Get the car warmed up and get the 2nd or 3rd gear log. Give her as much as it feels safe to preferably we would have a wot pull

[janpa7]

Originally Posted by Mustafa.e92

No I meant 2 separate logs lol. cold start dossnt look to bad trims are maxed though it’s trying to add lots of fuel. Get the car warmed up and get the 2nd or 3rd gear log. Give her as much as it feels safe to preferably we would have a wot pull

Just an update, after changing the injectors to index 12 (mine were never changed and index 8), I've had a massive improvement. I have almost no misfires anymore, the only misfire code I have is when I push my car for 15mn, I get a cylinder 4 misfire, which goes away on its own after 2mn. So, I changed coil from cylinder 4 to cylinder 3 to see if problem will move to cylinder 3, even though my coils are brand new...

The other problem I have is I have hesitation at about 3000rpm. And, even though my car's acceleration is satisfying above 4000rpm, I feel like it is not really delivering full power, probably because of that issue with cylinder 4.

I also started to get fuel smell in the cabin after changing my injectors, but I couldn't smell any fuel coming from the engine, there was no leak on the injectors and fuel lines in engine bay. There was also no fuel smell coming from under the seats in the back... So it's kind of a mystery...

The last problem I have, is that my idle is slightly unstable and car is slightly vibrating, but it used to be this way in the last 3 years, maybe I should clean my intake valves?

Here is a log I did today, with full accelerations https://datazap.me/u/janpatout/log-1...?log=0&data=25 Sorry for not having posted previously, but I couldn't afford to push my car in the state it was, it would have killed my engine.

Am I still running lean ? My AFR looks good to me, let me know please.

[Mustafa.e92]

That’s good it solved most the issues. Fuel smell is probably just some risidual fuel that leaked out when you did the injectors. Aslong as none of the lines are leaking it should disappear.
The logs are hard to read when they are that long but from what I could see bank 1 has higher trims and your having some timing pulls in cyl 2 and 4.
If plugs are good and coils are good I’d do the walnut blast it probably needs it

[SlowE92]

Originally Posted by janpa7

Just an update, after changing the injectors to index 12 (mine were never changed and index 8), I've had a massive improvement. I have almost no misfires anymore, the only misfire code I have is when I push my car for 15mn, I get a cylinder 4 misfire, which goes away on its own after 2mn. So, I changed coil from cylinder 4 to cylinder 3 to see if problem will move to cylinder 3, even though my coils are brand new...

The other problem I have is I have hesitation at about 3000rpm. And, even though my car's acceleration is satisfying above 4000rpm, I feel like it is not really delivering full power, probably because of that issue with cylinder 4.

I also started to get fuel smell in the cabin after changing my injectors, but I couldn't smell any fuel coming from the engine, there was no leak on the injectors and fuel lines in engine bay. There was also no fuel smell coming from under the seats in the back... So it's kind of a mystery...

The last problem I have, is that my idle is slightly unstable and car is slightly vibrating, but it used to be this way in the last 3 years, maybe I should clean my intake valves?

Here is a log I did today, with full accelerations https://datazap.me/u/janpatout/log-1...?log=0&data=25 Sorry for not having posted previously, but I couldn't afford to push my car in the state it was, it would have killed my engine.

Am I still running lean ? My AFR looks good to me, let me know please.

It looks like you still have a bunch of timing corrections .. i had similar symptoms and it turned out to be my 02 sensors on my cats.

[janpa7]

Originally Posted by Mustafa.e92

That’s good it solved most the issues. Fuel smell is probably just some risidual fuel that leaked out when you did the injectors. Aslong as none of the lines are leaking it should disappear.
The logs are hard to read when they are that long but from what I could see bank 1 has higher trims and your having some timing pulls in cyl 2 and 4.
If plugs are good and coils are good I’d do the walnut blast it probably needs it

Hi! Thanks for your answer! I want to give some updates. So, I tried to clean intake valves chemically on cylinder 4,5 and 6 after your recommendation, however, even after many attempts and hours spent, I couldn't remove more than 40% of the carbon, so I stopped. I haven't found anyone in my area who does walnut blast, so I'll do it one day when I go to Germany. Intake valve 3 and 4 seemed to be the dirtiest.

To solve my issue, I tried a new approach. I changed the seals and decouplers on my injector 3 and 4 (since I have recurring misfires on these cylinders, especially cylinder 4), injectors flow rates are all correctly coded. When removing injector 4, it was extremely easy to pull, like nothing was holding it and injector 3 only had a very slight tension holding it down. So, I think I have identified the issue: the injector 3 and 4 didn't completely seal. Which could explain why I was having a whining noise at 2k-3krpm (air coming out of injector bore?), unstable rpm, hesitation and misfire on these cylinders.

With new injector teflon seals and decouplers, the hesitation I was having decreased by 60%, acceleration was much stronger and so far cylinder 3 misfire is not coming back after 4 hours of driving. On some pulls, it even seemed as there were no issues anymore, the car would accelerate fine, no misfires, almost no hesitation...

However, cylinder 4 misfire is intermittently coming back, rpm is still slightly unstable, there is still a little hesitation at 2k-3krpm, and whining noise is less audible, but still there.

When I pulled the injector 3 and 4, only the tip was slightly black, but passed the teflon seal it was clean, even though I noticed some traces of black sooth on the decoupler, indicating that injector bore may not be completely sealing. But overall, my injector bore issue seems to be at its infancy and not too acute.

After reading a lot on the subject, I am thinking to try my luck again with new seals on injector 4. If it doesn't work, I may use teflon tape or double decoupler... What do you think? I didn't check if injector 4 was wiggling, maybe I should? But, the fact that it needed no effort to pull is a good indication in my opinion that the injector bore didn't seal correctly and may be damaged. I am surprised, because I only changed the injectors once on my car, it was the only time in the lifetime of the car, I don't think I improperly installed or improperly pulled them... very strange why the injector bore would fail like this...

Thank you for your advice again!

[janpa7]

Originally Posted by SlowE92

It looks like you still have a bunch of timing corrections .. i had similar symptoms and it turned out to be my 02 sensors on my cats.

Thank you. I changed the pre-cat O2, but not the post-cat O2 sensors. I will do it in the future, I have a set of new ones.

[Mustafa.e92]

You can get a cheap walnut blast kit and adapter for under $250. The valves get squeaky clean with minimal effort within minutes.
Make sure the injectore bore is clean and inspect it visually. The Teflon seals should be expanded, slid onto injector, compressed again, than installed right away.
Teflon tape and stuff are bandaid fixes. Oval happens due to improper removal of injectors usually from people wiggling them. Some jackasses forget the decoupler that can also cause that. If everything with the new injector install checks out. I’d look into the injectore bore. If you have access to a leak down tester that will also help you determine if that is the cause.
Proper fix is the pfi injector bore repair kit. You can search about it on Facebook forums much more active

[janpa7]

Originally Posted by Mustafa.e92

You can get a cheap walnut blast kit and adapter for under $250. The valves get squeaky clean with minimal effort within minutes.
Make sure the injectore bore is clean and inspect it visually. The Teflon seals should be expanded, slid onto injector, compressed again, than installed right away.
Teflon tape and stuff are bandaid fixes. Oval happens due to improper removal of injectors usually from people wiggling them. Some jackasses forget the decoupler that can also cause that. If everything with the new injector install checks out. I’d look into the injectore bore. If you have access to a leak down tester that will also help you determine if that is the cause.
Proper fix is the pfi injector bore repair kit. You can search about it on Facebook forums much more active

Thanks for your answer again!

So, yesterday I removed the injector 4, this time I had to apply force to pull the injector out (with the proper tools), which was encouraging. I properly removed the old seal, expanded, inserted the new seal and compressed it with the correct tools for N54 (and of course decoupler was on!).

When I reinstalled the injector, it really felt as if it seated well into the injector bore, it felt very tight and nice. And, the injector didn't wiggle at all when I very gently pushed the injector sideways with minimal force. The injector bore looked clean.

The symptoms didn't improve much, maybe by only 5%
But, I still get the misfire on cylinder 4 on WOT and misfire on cylinder 3 re-appeared like magic... hesitation is also still here.

So now, I am back to walnut blast. I know I can buy the tools to do it (even though I don't have air pressure), but turning the engine and making sure the valves are tightly closed is tricky and I would prefer a professional mechanic do it instead of me. I'll try again to find one in my area or near...

I'll also do leak down and compression test if walnut blast doesn't solve the issue (I don't have the tools).

I'll also buy 2 new plugs and change them on cylinder 3 and 4 to see if that solves the issue tomorrow. My plugs have 1k on them, but maybe they were incorrectly torqued by the mechanic or defect...

I'll keep you informed. Have a great week!

[Biggsie]

Update on this? Did you ever do the o2 sensors?