[listed5]

I bought my car about 2 months ago (used 09 with 55k) it had what seemed like a slight at miss idle. A cylinder seems to fall out every 8-10 seconds when idling and warm. After getting some more wheel time in, I noticed the idle was oscilating (from 700-800 rpm) similar mannerisms to the a/c compressor running, which it IS NOT!! I decided to change the plugs and found a lot of black soot on cylinder 5's plug. All of the others were normal in appearance (tanish powdercoat). Additionally, the black plug had a fuel odor to it. In most cars, black means rich. Not sure about DI. Does this mean the Injector needs to be replaced? Sorry about the pic quality, it's hard to capture.
Thanks,
Chris

[Joshboody]

could be a leaky injector or bad coil, but i would think you would have misfire codes if this was the case. Let us know what you find out.

[listed5]

Yeah, never had a check engine light. My only code is for the muffler flapper (I disconnected it's power wire)... I'll keep you posted if I make any progress! Luckily my car falls under the injector recall! I'm not sure if my local dealers will offer the service to me since I have zero relationship with them...

[michael1284]

turn on macro mode or focus properly.

[raceyBMW]

macro mode needs to be your friend, cause we can't see shit!

Very well could be a leaky injector though. If you aren't throwing codes, maybe try running some fuel injector cleaner though the gas tank and see if that does anything.

[etichi]

OP, no offence but look up depth of field. It will help with your "picture is a thousand words." Your palms are more in focus.

[drfrink24]

So... did changing sparkplugs fix this issue?

[orionredwing]

I have the exact same problem, but mine is on cyl 3. I swapped out new spark plugs a few weeks back and noticed the same thing. I have clearer pics and will post when I get home.

I swapped coil packs after the new plugs were installed, took it out for a 20 mile spin, came back, noticed the blurp in the idle, and decided to remove the spark plugs in the morning after the engine was cool. With only 20 miles, my plug #3 was black w/ fuel smell. It's not the coil pack (swapped), it's not the spark plug (brand new), so the only thing left is the injector. My injectors were swapped 30K miles ago, so these are not factory original. I have 72K on my car.

Symptoms:

- When the car is idling, there is a little blurp every 10-20 secs, which is indication of a small misfire.

- But the misfires are not serious. I have about ~200 mins of track time on the car since new plugs were installed w/ NO misfire codes thrown. No observable impact while driving.

- Fuel economy is about the same. Maybe 0.5 to 1mpg worse. That's within the variation of the right foot, but I feel mpg is slightly worse, but not significant. I write down mpgs, etc in a little notebook at every fill up.

- Did not dyno car so don't know if there's a loss in power. My butt had long since adjusted.

- Added Chevron Techron concentrated. Blurps went from ~8 secs to the 10-20 sec intervals I reported above. While I was a firm believer and user of Chevron Techron in my previous cars, all the DI related discussions meant I did use any treatments on the 335i. This is the first treatment in 72K miles (I used to do it every 5-10K), and with the slight positive benefit noticed, I plan on restarting the routine. I silently sided w/ the naysayers who said Techron does not work in DI cars, despite being a Techron fan myself. But now I'm back to being a believer that it does help. Call the benefits minor, or whatever, but this isn't a Techron discussion thread.

[listed5]

Originally Posted by etichi

OP, no offence but look up depth of field. It will help with your "picture is a thousand words." Your palms are more in focus.

Haha. Would I take offense to this??? I love cars! NOT photography . Anyway, Redwing seems to have the exact same problem I do! I use Shell at every fill up, but have only owned the car for 2 months. Seems replacing the injector is the answer....
Chris

[YngPhllyKd]

I've actually been noticing this recently. Wasn't sure what was going on. And i didnt get any codes for misfires though.

[Joshboody]

Originally Posted by orionredwing

I have the exact same problem, but mine is on cyl 3. I swapped out new spark plugs a few weeks back and noticed the same thing. I have clearer pics and will post when I get home.

I swapped coil packs after the new plugs were installed, took it out for a 20 mile spin, came back, noticed the blurp in the idle, and decided to remove the spark plugs in the morning after the engine was cool. With only 20 miles, my plug #3 was black w/ fuel smell. It's not the coil pack (swapped), it's not the spark plug (brand new), so the only thing left is the injector. My injectors were swapped 30K miles ago, so these are not factory original. I have 72K on my car.

Symptoms:

- When the car is idling, there is a little blurp every 10-20 secs, which is indication of a small misfire.

- But the misfires are not serious. I have about ~200 mins of track time on the car since new plugs were installed w/ NO misfire codes thrown. No observable impact while driving.

- Fuel economy is about the same. Maybe 0.5 to 1mpg worse. That's within the variation of the right foot, but I feel mpg is slightly worse, but not significant. I write down mpgs, etc in a little notebook at every fill up.

- Did not dyno car so don't know if there's a loss in power. My butt had long since adjusted.

- Added Chevron Techron concentrated. Blurps went from ~8 secs to the 10-20 sec intervals I reported above. While I was a firm believer and user of Chevron Techron in my previous cars, all the DI related discussions meant I did use any treatments on the 335i. This is the first treatment in 72K miles (I used to do it every 5-10K), and with the slight positive benefit noticed, I plan on restarting the routine. I silently sided w/ the naysayers who said Techron does not work in DI cars, despite being a Techron fan myself. But now I'm back to being a believer that it does help. Call the benefits minor, or whatever, but this isn't a Techron discussion thread.

purchased a bottle of techron at lunch thanks to you. stupid question: our fuel fill flapper is deep inside the tank tube. Do you use a skinny funnel, or something long to open the flapper before pouring?

[David1]

Placebo. You have 2000+ psi at the injector. If it is not clean from that nothing will clean it. What happens in a DI motor when an injector is worn, the tip is worn away and this lets the spray pattern hit the spark plug soaking it. BMW calls this spay diversion and requires injector replacement.

[orionredwing]

haha nice

I just use the skinny funnel included in the bottle, and wiggle it around to get the flow going. You're right, as the risk of slightly lifting it out of the flapper to create an air gap (to allow flow) may result in overspill.

Originally Posted by Joshboody

purchased a bottle of techron at lunch thanks to you. stupid question: our fuel fill flapper is deep inside the tank tube. Do you use a skinny funnel, or something long to open the flapper before pouring?

[Joshboody]

Originally Posted by David1

Placebo. You have 2000+ psi at the injector. If it is not clean from that nothing will clean it. What happens in a DI motor when an injector is worn, the tip is worn away and this lets the spray pattern hit the spark plug soaking it. BMW calls this spay diversion and requires injector replacement.

very good point. they can also leak... a good test is if you have rougher starts after letting the car sit for a bit... day or 2. If they are leaking when not under pressure, i'm sure it's more severe with engine on.

[bv1]

Did you end up replacing the injector? Did it fix the problem? I just posted the exact same problem.

[pimple]

Originally Posted by Joshboody

could be a leaky injector or bad coil, but i would think you would have misfire codes if this was the case. Let us know what you find out.

From my experience, misfires due to bad ignition coils aren't always accompanied with misfire codes. Intermittent misfires in my car under heavy load were indications of pending ignition coil failure. Once the ignition coils failed completely, the check engine light came on, misfire codes were thrown, and the engine misfired badly. On my '07 N54, 3 ignition coils went bad around 50k miles (on separate occasions).

[Dr_Dirt]

Originally Posted by pimple

From my experience, misfires due to bad ignition coils aren't always accompanied with misfire codes. Intermittent misfires in my car under heavy load were indications of pending ignition coil failure. Once the ignition coils failed completely, the check engine light came on, misfire codes were thrown, and the engine misfired badly. On my '07 N54, 3 ignition coils went bad around 50k miles (on separate occasions).

Does this mean that a fouled plug is due to bad coil?

[tibra1]

A good guide for spark plug analysis..

http://www.gnttype.org/techarea/engine/plugs.html

#5 def looks carbon-fouled..did you notice if the plug was "wet" or gas soaked..tell tale sign of leaky injector

changing ur sparkplugs every 20K is optimum.

Another memeber reported the exact same case with cylinder #5 spark plug

http://www.e90post.com/forums/showthread.php?t=590771

[pimple]

Originally Posted by Dr_Dirt

Does this mean that a fouled plug is due to bad coil?

I don't know, but I'd doubt it. Here are my plugs at 50k miles, cylinders 6, 5, 4, 3, 2, 1 from left to right. (Dealership swapped plugs 1 and 2 when the 1st coil went bad. When the next coil went bad, 2 and 6 were swapped. When the 3rd coil went bad, I just replaced all plugs and coils. Coils 2, 3, and 4 were the ones that failed, I think.). Car was completely stock up to this point. Oil first changed @ 8k miles and then every ~4k miles after that.

[listed5]

Sorry not to have kept up with this thread! I called VOB BMW (albeit hesitantly) several times and never got a return call. I eventually called BMW of Silver Spring; they said my car was covered under the recent injector recall and scheduled an appointment for the following week. After 2 days in my loaner KIA, I had my 335 back again with new injectors on cylinders 3, 5, and 6; as well as a new HPFP and low pressure sensor. My idle hiccup is no more and the cylinder 5 plug looks just like the others! Thanks BMW of Silver Spring!!!

[bimmertt]

Techron might be a placebo, but it seems to have resolved my issue. After changing plugs I noticed hiccups in my idle. I threw in a bottle of techron at my next fillup and after going through half a tank, my idle is smooth now. Don't know how else to explain it.