[mondevx]

Just bought the car recently (2009 BMW 335i 6MT) and started to have this strange issue.

While driving on the highway the car went into limp mode, after restart the car seems to idle fine, but the limp mode comes back after a few minutes while driving and seems to stutter quite a bit while trying to accelerate.

After checking with the scanner the following codes show up:

2E9F Oil State Sensor
29CF Combustion Misfire on Cylinder 3
29Cd Combustion Misfire on Cylinder 1
29CC Combustion Misfire on Several Cylinders
030FFH/12543 Undocumented Code


After sitting for a few hours no codes show up but the car makes this strange noise while revving the engine. I also checked the oil level and it checks out "OK" and doesn't show that it's low or anything of that sort.

No visible leaks near the engine bay either.

Please advise, thank you.

[Physics]

How many miles on your current plugs and coils?

[mondevx]

I believe the spark plugs were last changed around 60k miles or so based on the carfax that I got from the dealer, I'm at 75k now.

After tons of research I believe this sound is caused by a loose spark plug.

Going to change out all plugs (for peace of mind) and see how it performs.

[mondevx]

So after changing my spark plugs the noise is still there, not really sure what to do at this point other than possibly changing out all coils..

Very strange noise, while driving it will intermittently disappear and reappear, any ideas WTF this is?

[924er]

Change ur coils it won't hurt. Could also be injectors. How did ur plugs look?

[stieny]

It sounds like rod knock in that second video.

[Physics]

You are due for new coils at this point as well.

[mondevx]

Here were the plugs when I pulled them out, #1 at the bottom and #6 at the top:




I refuse to believe it's a rod knock at this point because the car would not be misfiring and throwing misfire codes because of a rod knock, or could it?

To me it sounds more electrical (sparking noise) than actual knock. Do bad coils ever make this noise?

I'll be able to get my hand on two spare coils today and will attempt to swap them out to see if anything changes.

[lichtgelb]

That noise sounds like fuel detonation in the exhaust manifold. Would make sense that you don't hear it until the engine comes up to temp. Does your exhaust smell fuel rich on a cold start? If new coils do not fix this you need a compression test on cylinder 1 for sure.

Look for higher positive values in the ST and LT fuel trim on bank 1 compared to bank 2. You could swap the coil from cylinder 1 to cylinder 6 and see if the fuel trims change from one bank to the other. However, given the state of that plug and noise I wouldn't run the engine much until you can rule out bad ignition or lack of compression. The DME will lean out the fuel mix due to a misfire and running a turbo engine in a lean state is not good.

[mondevx]

Ok so I found out the coils were "Delphi" brand, and I had two spare Bosch OEM coils to swap out. I swapped out cylinder 1 first, absolutely no difference, then proceeded to swap out all cylinders with the Bosch coil, sounds exactly the same.

Here is a video of the sound with the cover off, definitely sounds electrical.

I have an appointment at BMW for next Monday (out of warranty) hoping they'll tell me what the hell is going on here.

Worst case scenario I might buy the Route 66 warranty before turning it in to the dealer.. Hoping it's not something major..

[mondevx]

Just a little update on this issue:

It was the injectors!

I disconnected my problematic cylinder 1 just to test it out, and lo and behold the clicking clatter is gone.

With this info I checked all of my injectors, and I found out that I still have an index 7 injector in the 3d cylinder (on recall), and index 8 on the 1st and 2nd.

The last 3 have index 11, so it seems like I've found out why the engine roughs slightly rough on cold starts.

Here is how they all are:

Cylinder 6: 1353 758 5261-11
Cylinder 5: 1353 758 5261-11
Cylinder 4: 1353 758 5261-11
Cylinder 3: 1353 756 5138-07 RECALL (MISFIRE)
Cylinder 2: 1353 758 5261-08
Cylinder 1: 1353 758 5261-08 (MISFIRE)

I've read on previous posts that you cannot mix different indexes, is that still the case? Here I have a little bit of everything, which is definitely not great from what I hear.

The car will be going to the dealer on Monday, so I'm pretty sure they'll swap the recalled injector, but not so sure about the others, thoughts?

[Spun Crankhub]

Glad to hear you found out the problem. I was going to suggest you check your gatling guns to make sure they were working fine.