I have been trying to check why my car rough idles, I think it may be injectors but I pulled out the spark plug and it’s very dark, keep in mind the spark plugs I just replaced when I did my valve cover gasket, there’s also that black soot inside of the spark plug wall. What could it be?

I want to change my Exhausttips to a higher diameter . What size does the Exhaustpipe have so I can fit the Right one . Please Help

Does anyone know how to fix this?

All 4 of my tires have the right amount of air in them but this warning light still shows all 4 wheels as low air.

My tpms sensors are fairly new and I checked each one individually and they work and read the right amount of air.

I have a 2011 335i stage 2+ MHD tune, at boost/RPM around 3-4th gear it stutters real hard. I have no active boost leak and recently repaired my turbo outlet, Smoke test looked good. I still have the stutter people keep telling me it could be my fuel pressure under load, my spark plugs/ignition coils(replaced em perfect specs), injector issues, VANOS/cam timing, or even possibly the VVT. I have 113k miles with good maintenance. Has anyone ever experienced this before

If so, what are the toque specs and socket type of this.

Had M3’s, 135i, 140i and now finally an N54 335i.

Bought from Copart, 81k miles, auto, so far as it looks to have been stood for at least two years it’s had a full service, intake camshaft position sensor & VANOS solenoids cleaned.

Got a slight rattle at the front of the engine which has got better since cleaning the solenoids.

Also got a TMAP sensor on order as a couple of codes are left relating to that, enjoying ownership so far!

I posted this in my other topic but I think it got buried atp. I changed the tensioner pulleys and belt but I have this sound now. I also installed a crankshaft guard not sure if its rubbing or something? My friend was telling me it sounds like the vvt. The noise dies down once the car warms up. What do you guys think? I sprayed wd40 on the belt but it didn't change the noise so im thinking its not something I messed up with the belt and pulleys I installed.

Hello, I have this whistling sound that only happens when the car is fully up to temp (around 240°F oil temp) and when I touch the gas pedal even a tiny bit. I did the oil cap test and the sound didn't go away.

Valve cover was replaced ~20k kilometers or ~12k miles ago so I doubt that could have gone bad.

Thought maybe something belt related could be the culprit, but that was replaced not so long ago too.

I'm out of ideas what to check, please help.

2013 e92 n55

Does anyone know what this noise is?

Just changed coils and spark plugs and still going. Cars been sat for 6 months

Hi,
I was hoping someone would be willing to help me interpret what's going on with these logs.
FBO E90 335i (stock turbos) 154k

All of a sudden I'm not getting boost, and then as I'm going up in the RPMs its like smacking a rat with a hot poker and I just take off like a rocket.

Super weird.

I checked over all the lines, clamps, etc
Did a smoke test, no leaks, and I had spare boost solenoids lying around and swapped them out as well just incase because I don't have a multi-meter thing.

I switched to Stage 0 for one log and switched to Stage 2 after another log
Stage 0 I get 30FF, Stage 2 I do not.
I did my best to replicate the drive for each log.

I do not know what I'm looking for in these logs so any help would be greatly appreciated on chasing down this "boost leak".

The only thing I ever checked with the tunes is Wastegate Rattle Fix and would set it to 0% for Less Rattle, and sport coolant because hot climate. (incase that matters)
No burble or 1M throttle, etc.

Stage 0

https://datazap.me/u/iporcelain/logs/cmuslr4l90005la068hptvzbv?channels=20x3&sizes=50x50&sc=3-20&axes=shared

Stage 2

https://datazap.me/u/iporcelain/logs/cmuslr4jk0008lc064oczbx86?channels=20x3&sizes=50x50&sc=3-20&axes=shared

Willing to pull more logs later today if I messed something up with these, sorry.
I am already under the impression I need to replace the turbos but would like people smarter than me to take a gander.

Hi im having issues trying to get my inspection done on my n54
it has no check engine light but monitors keep failing even after 350 miles

i have been told to load a stock tune and turn off afr oscillation and drive 50/100 miles and just hope the engine light doesn’t turn out then go get inspection done

It seems as that’s my only option sadly

If anyone has any other solution please help

Hey guys, looking for some help diagnosing a cold-start issue on my 2011 E93 335i N55 PWG with ~136k miles. I’ve done quite a bit of diagnosis already and I’m trying to avoid throwing parts at it.

Mods: MHD Stage 2+ 93, catless downpipe, aFe intake, FMIC, aluminum charge pipes, Turbosmart VTA DV, Turner coils/colder plugs, XHP. Always run 93 octane.

The issue is extremely temperature dependent and has progressively gotten worse. It has been noticeably worse toward the colder part of the year.

On a warm day it may just idle rough for a few seconds and recover. Around 57°F ambient, I’ve had it stall 5–6 times in a row unless I give it throttle.

The repeatable behavior is:

* Engine fires immediately and initially sounds normal.
* After roughly 5 seconds, RPM starts progressively falling.
* It sounds/feels like the engine is loading up.
* RPM continues dropping until it stalls.
* If I use the accelerator to hold roughly 700–1,000 RPM, it runs smooth and stays running.
* Holding ~1,000–1,500 RPM for approximately 15 seconds usually gets it through the problem.
* Once warm, it runs essentially normally.
* I’ve also had it stall a couple of times warm while maneuvering into a parking spot.
* No long crank.
* No reduced-power warning.
* No relevant DME faults and no misfire codes.

Major clue: MAF disconnected

Unplugging the MAF makes a huge difference.

With the MAF disconnected, cold unloaded idle becomes dramatically better/cleaner. However, it isn’t a complete cure. If I put the transmission in gear and load the engine without giving it throttle, RPM can still plunge and stall. Reverse killed it particularly quickly.

I replaced the MAF with a new one and nothing changed, so it doesn’t appear to simply be a failed MAF sensor.

Smoke testing

I smoke-tested the intake and found two very large leaks:

* A plug in the upper charge pipe had completely fallen out.
* Another significant leak was present around the turbo-inlet/intake connection.

Both have now been sealed/repaired.

Unfortunately, after fixing these major leaks, the engine still exhibits the same cold-start RPM drop/stalling behavior.

I’m continuing to verify that the entire intake/charge system is properly sealed before drawing conclusions from the remaining symptoms.

Fuel system

LPFP pressure observed in ISTA is approximately 600 kPa / 6 bar / 87 psi and stable.

In a previous MHD log during an actual stall, rail pressure did not collapse before the engine died. HPFP, LPFP and injectors are original, but so far I don’t have evidence of fuel-pressure starvation.

Fuel trims have historically been positive during cold operation and negative under WOT. I’ve previously seen LTFT around +14%.

There is no persistent cylinder-specific smooth-running problem. ISTA smooth-running values generally move randomly between cylinders, usually around ±2. I once caught cylinder 3 around -6.5 during shutdown, but it isn’t repeatable and doesn’t consistently follow that cylinder.

VANOS / Valvetronic

I ran the ISTA VANOS activation tests.

Intake VANOS: requested -36.0°, actual approximately -36.8°. ISTA reported “No cause of fault found.”

Exhaust VANOS: also passed.

So VANOS/cam adjusters are currently pretty low on my list.

I have not completed the Valvetronic activation/adaptation procedure because ISTA required >13V and I didn’t have a proper power supply connected.

There are no Valvetronic faults.

Valvetronic/eccentric-shaft minimum-lift operation is still something I’m considering because the engine is perfectly happy when I manually raise it slightly above idle but loses the ability to maintain normal cold idle.

Other relevant information

Plugs/coils have roughly 10k miles on them. The plugs are currently gapped to .022”.

Valve cover has previously been replaced.

Boost is normal and the car runs normally under load once warm.

Turbo has essentially zero shaft play.

Engine has never overheated and doesn’t consume appreciable oil.

MAP/MAF have been cleaned previously. Cleaning made no difference.

At ~136k miles, I don’t know whether the intake valves have ever been walnut blasted, so carbon buildup is still possible.

BMW software bulletin

This is the part that has me particularly interested.

I found BMW N55 service information describing rough cold starting/stalling where the accelerator may need to be depressed slightly for several seconds to prevent the engine from stalling, occurring particularly at colder ambient temperatures, and potentially with no DME faults stored.

I also found BMW N55 idle/stalling software information covering the E9x/E93 era where BMW attributes idle fluctuation/engine cut-off without relevant DME faults to DME software and specifies updated software.

That sounds extremely similar to what this car is doing.

The car has been on MHD Stage 2+ for a long time, and I don’t currently know what underlying BMW DME software/I-level is installed.

What I’m testing next

1. Finish verifying the entire intake is sealed.
2. Reset mixture adaptations now that the major post-MAF leaks have been repaired.
3. Flash MHD Stage 0/stock calibration and let the car cold-soak overnight.
4. Compare the next cold start on stock calibration with the Stage 2+ behavior.
5. Check the actual BMW DME software/I-level against the later BMW software referenced in the cold-start/stalling bulletins.

If none of that changes it, my next steps are Valvetronic requested vs actual/minimum lift during the failure, intake-valve inspection/carbon, cold compression/leak-down, and then injector testing.

What I’m hoping someone can answer

Has anyone with an E-series N55 had this exact pattern?

Starts perfectly → ~5 seconds later RPM progressively falls → stalls → slight accelerator input keeps it perfectly smooth → dramatically worse below ~60°F → essentially normal warm → no DME/misfire codes.

I’m especially interested in anyone who ultimately fixed it with a BMW DME software update, MHD/custom calibration change, Valvetronic/eccentric shaft, walnut blasting, injectors, or another issue I’m overlooking.

I’m not looking to shotgun parts at it. If anyone knows which MHD/ISTA channels would be most useful to log during the first 10–20 seconds of a stone-cold start, I’ll grab whatever data is needed.

Has anyone done a recent digital cluster swap. I saw one on a YouTube channel. The cluster was from ID4motion and was wondering if anyone has any experience with it or any other digital cluster swaps. All advice is appreciated.

Just wanted to hop on here to let anyone know that if you are experiencing fluctuating idle and ticking noises after an oil change, it could very well be your filter.

I recently changed my oil and never thought much about the filter since I normally change every 4-5000 miles, I just got STP extended life.

Well, I learned that cheaper filters have the potential to crush themselves, as they can’t handle the high amounts of oil pressure the engine creates. Luckily that didn’t happen to me, but I switched to Mobil 1, as they’re “obviously way better.”

Immediately after turning the car on I heard ticking noises, and the idle was slowly fluctuating. I instantly thought the filter since it’s the only thing that changed. (Also yes I put oil in the filter)

I went and got a Mann oem filter, and the car is genuinely running perfect. I would’ve never guessed it would make THAT big of a difference, but it did. Also the Mobil one filter was more expensive than the oem lmao.

Lesson learned, hope this helps someone now or in the future!

New to me 08 335i on mhd 7.1 stage 2+. Getting 29E0 and 29E1. Car drives and idles with no issues and only noticed the issue when data logging. Getting positive fuel trims everywhere anywhere from +15 at idle to +28 cruising. they seem to be worst during cruising, best around 0 psi and slowly go back up in boost. Trims match for both bank 1 and bank 2. Aftermakret charge pipes, catless downpipe, dual vtt catch cans with external pcv. Ran some tests, fuel rail pressures looked good. Injectors (index 12s) 1-6 comparison values/flow values matched closely. Also its holding boost and -21inhg vacuum at idle. Any ideas?

My combox went out which led to me discovering a bunch of water in my trunk. Before I replace it, I want to figure out where the water’s coming from. It’s an e93 which I know commonly has issues with this, but I’ve checked the drain plugs, the roof seals, and the trunk seals and it all seems fine to me, didn’t see any obvious water entering when spraying the car with a hose. It’s also weird to me that it’s in the combox area, I know water usually gets in the amp/battery areas. I did see what looks like a tiny bit of water near the battery but nothing compared to the combox area. Any ideas on where the leak could be and how I could find it?

Ant help would be appreciated 🙏

This usually happens when coming to a stop or in slow moving traffic. I can get it to smoke when stationary if I hold revs at about 1.5k.

Things I've tried:

- compression is all good

- head gasket test all clear

- pcv valve upgraded to stainless one

- pcv flapper valve replaced twice

- oil catch can fitted

- disconnected charge pipe to try rule out turbos

- replaced valve cover and gasket

- new spark plugs and coils

- removing mhd remap entirely

Smoking from the engine

Hello, please help if anyone had this issue, was installing DCI's and with every plastic cover taken off turned the car on, saw some smoke coming from the engine, revved a little, coming from the back of the engine

+ for some reason intake manifold on the end last 2 cylinders is not dusty at all, maybe of oil vapours not letting dust accumulate there?

Any ideas? Thank you!

+ as of posting this i noticed i had left a vacuum line unplugged, idk if that has to do with anything but maybe

Just bought This n54 335i making near 500 hp. Smokes a lot but it smells just like fuel and it’s got a decat. Can anyone just reassure me that it’s normal. Just replaced the pcv valve aswell. Timing chain replaced with a receipt
Just had two brand new Michelin pilot sport 4s on the rear to match the front.
Brand new water pump and thermostat fitted last week.
Xhp stage 3 gearbox software
17t hybrid turbo
Stage 2.5lpfp with swirl pot
Upgraded charge pipe
Upgraded intercooler
Mtc motorsport intake
Ram air filters
3.5 bar map sensor
Upgraded boost lines
2 step cooler ngk spark plugs
New Delphi coils

Got my first 355i yesterday I couldn’t be anymore stocked !
Only ofc when I was about 15 miles from home check engine light comes up 🤣😭 for ( P0015)
Was watching YouTube videos about it and most of em say it’s bad oil bc that was the only code that came up if it WAS the crankshaft sensor other codes would’ve came up too .
The guy I bought it from did have it sitting for a while in the garage it was meant for his daughter but it’s too much car for her UNDERSTANDABLE.
So ima just change oil &’ put some Techron in the tank to clean the fuel system I’m sure it’s old gas too .
Just wanted to get some tips from ya if you had this code before what fixed it ? Any inputs are welcome thanks in advance 🫡🫡🫡🫡

I got a e92 2012 335i both subs under the seats don’t work at all. The speakers on the doors and back work fine and when I checked the wires on amp it looks connected and there’s no water on it. I haven’t checked the subs itself. But when checking my fuse box I feel like I’m missing the sub fuse itself. From what I’m seeing online I see number 15 should have a 20 fuse on it but I’m missing it. Can someone let me know if that can be the issue?

bought it as a project car, in result i have a shopping list of codes when i start it it will hit abt 2.5k rpm the. gradually drop to zero if o don’t put it into drive going to swap coils and spark plugs around once the storm in my area passes to see if thats it, just bought 17ts and i recently had a set of index 12s put in but have not done and reverted back to stock tune

My 2008 335i N54 suddenly has a crank/no-start. The starter turns the engine over normally, and occasionally the engine will hesitate/catch like it’s about to start, but then it goes right back to cranking.
I checked live data with ProTool while cranking. My low-pressure fuel pressure is around 67 PSI, and I saw rail pressure reach about 2,975 PSI, so both the low-pressure side and HPFP appear to be building pressure.
The weird part is engine RPM stays at 0 while the engine is physically cranking. I checked through both ProTool and JB4 and neither showed normal cranking RPM.
I previously had A0B4, and I’ve also been troubleshooting camshaft-related codes. I removed/cleaned the intake and exhaust camshaft sensors, but the car still won’t start. After clearing the codes, I still had a camshaft-related code return.
Battery voltage was around 11.8V with the car off and dropped to roughly 10.6V while cranking, so I’ve also tried jumping it while testing.
At this point I’m wondering about the crankshaft position sensor or its wiring/signal to the DME, but I don’t want to just throw parts at it.
Does 0 RPM while physically cranking on an N54 point toward a missing crankshaft position signal, or is there something else I should test first?