Cylinder 3 Misfire

[OneTwenty8i]

I have a 2013 128i with 27k miles on it. A month ago I got a misfire on cylinder 3, rough idle, weird rpm movement, misfire noise. I assumed it was the spark plugs, I bought double platinum OEM Bosch spark plugs from autozone and installed those but I still received a cylinder 3 misfire code.

Now that I knew it wasn't the spark plugs, I was suspicious of the ignition coil packs. I switched cylinder 3 coil pack with cylinder 1 coil pack but still received a cylinder 3 misfire code. Now I'm stuck and asking for your help. My car had bad gas mileage the day it was purchased. (17.6 mpg driving 50% city 50% highway) I'm thinking it might be a fuel injector? Any advice would help, I'm really sick of not having a working car atm lol.

[OneTwenty8i]

Bump

[desertman123]

Were you scanning it with a generic OBD2 scanner or a BMW/fancy one that can read manufacturer codes?

Might have a dying/dead eccentric shaft sensor.

Injectors USUALLY aren't an issue on this motor.

Also it's probably unrelated/won't help, but clean your MAF and VANOS solenoids. If anything it'll be a nice tune-up.

[OneTwenty8i]

Originally Posted by desertman123

Were you scanning it with a generic OBD2 scanner or a BMW/fancy one that can read manufacturer codes?

Might have a dying/dead eccentric shaft sensor.

Injectors USUALLY aren't an issue on this motor.

Also it's probably unrelated/won't help, but clean your MAF and VANOS solenoids. If anything it'll be a nice tune-up.

I was using a generic obd2 scanner. Do you know if there is a diy cleaning Mac and vanos solenoids? I'm actually interested in doing that.

[chris_flies]

Originally Posted by OneTwenty8i

I was using a generic obd2 scanner. Do you know if there is a diy cleaning Mac and vanos solenoids? I'm actually interested in doing that.

MAF cleaning is easy. Get some good MAF sensor cleaner from the local auto parts store, CRi products work for me, BTW. Pull out the intake air box:

2x 10mm bolts located near fender, unscrew these.
1x Hose clamp on back side, just downwind of air box, loosen this (not too much, else it'll flip over and you will regret everything)
1x MAF connector, disconnect it (a slim flat-head helps, or smaller hands than mine)
1x Weird friction joint with snorkel at top of box, pull apart

Now, pull the air box out, and spray down your MAF sensor repeatedly from a few angles. Allow the spray to dry out COMPLETELY (a short circuit = MAF failure = many $$$ flying away). Do everything in reverse.

About the VANOS solenoid cleaning, I have a vague idea, but not a good enough idea as to explain it here. Here's the TIS on removing them, you can google as to how you actually clean them (compressed air, I think):

https://www.newtis.info/tisv2/a/en/e...ontrol/EcNfhJk

Good luck!

[OneTwenty8i]

Originally Posted by chris_flies

MAF cleaning is easy. Get some good MAF sensor cleaner from the local auto parts store, CRi products work for me, BTW. Pull out the intake air box:

2x 10mm bolts located near fender, unscrew these.
1x Hose clamp on back side, just downwind of air box, loosen this (not too much, else it'll flip over and you will regret everything)
1x MAF connector, disconnect it (a slim flat-head helps, or smaller hands than mine)
1x Weird friction joint with snorkel at top of box, pull apart

Now, pull the air box out, and spray down your MAF sensor repeatedly from a few angles. Allow the spray to dry out COMPLETELY (a short circuit = MAF failure = many $$$ flying away). Do everything in reverse.

About the VANOS solenoid cleaning, I have a vague idea, but not a good enough idea as to explain it here. Here's the TIS on removing them, you can google as to how you actually clean them (compressed air, I think):

https://www.newtis.info/tisv2/a/en/e...ontrol/EcNfhJk

Good luck!

I really appreciate it my guy. You're a good man.

[chris_flies]

Originally Posted by OneTwenty8i

I really appreciate it my guy. You're a good man.

No problem! I know I am...

[Mr Gasser]

still have to rule out Fuel Injector.

[desertman123]

I would highly recommend a BimmerGeeks USB-OBD2 cable with BMW Standard Tools (INPA mainly). Or a more expensive but much simpler route is CarlyBMW with the phone app.

Scan with a BMW scanner and let us know.

For VANOS solenoids, I just cleaned it with brake cleaner and let dry. I also gave the hole in the engine where they go a nice cleaning too - a little bit of oil seeps out.

[nato-main-man-5am]

Will be curious to hear how this one panned out. I just started getting a code which Carly says means "0029DO Misfire detection cylinder 4 in third Firing order".

I haven't yet moved the coils around to see if the problem follows the coil. Hope that it does. That would be the simplest fix....

[Dackelone]

Move your spark plug to another cylinder and see IF your misfire moves. Only the plug.

Aftermarket plugs cause issues with our cars. I would only use BMW dealer bought plugs.

Also make sure your coil pack connector re-seats correctly. See video...

IF you still continue to have a misfire... I would suspect a bad injector and or carbon buildup.


Dackel

[nato-main-man-5am]

Originally Posted by Dackelone

Move your spark plug to another cylinder and see IF your misfire moves. Only the plug.

Aftermarket plugs cause issues with our cars. I would only use BMW dealer bought plugs.

Also make sure your coil pack connector re-seats correctly. See video...

IF you still continue to have a misfire... I would suspect a bad injector and or carbon buildup.


Dackel

Thanks! I will give it a try.

Is carbon build up visibly obvious?

[Dackelone]

Originally Posted by nato-main-man-5am

Thanks! I will give it a try.

Is carbon build up visibly obvious?

Yes, once you pull off the intake manifold. But its a pain in the butt. IF you do that... consider replacing your oil filter housing(OFH) gasket as well.

Normally 128i's don't have carbon buildup issues like the 135i's do.


I really think you just have a bad spark plug(aftermarket) or improper plug gap.


Dackel

[nato-main-man-5am]

These are still the original plugs. Supposed to last 100k miles.

[nato-main-man-5am]

Swapped two coils to see if the failure moves. Test drive now.

[nato-main-man-5am]

Most strange. Just swapping the coils.... and no more misfires so far. I wonder whether it was seated poorly before or maybe there was some corrosion or carbon that got stripped just by moving and re-seating them.

[c0mmon]

I had this problem and tried so many stupid things to fix it. Swapping Rubber Boots from 3(which was getting the misfire as well) and 1 fixed it for me - 2500 miles ago *knock on wood*

[nato-main-man-5am]

Interesting. I'm not sure what a Rubber Boot is in this context. Do you have a link to a photo or diagram?

[NorthernDancer]

All coils have a spark plug boot at bottom, maybe about 2" long.

[nato-main-man-5am]

Thanks, I just think of the whole housing that sits on top of the spark plug as "the coil" so I learned something new. Thanks.

[OneTwenty8i]

Took it to a dealership and they replaced all coils, valve cover gasket and fuel tank sensor. The misfire is gone now and it was all covered under sulev warranty.

[mikeR]

I have the exact same issue. I did basically the same debug process. swapped plug, injector and coil. I then called my local bmw mechanic. I have spent a bit of money there so he is giving me free advice. He told me to call BMW NA and ask about the hpfp warranty and it applies to my car. I did that and provided the vin. The BMW NA rep said that my car has an extended warranty on my hpfp applies 10 years 120k miles. He then told me to contact the local BMW dealer and have them look into this on my car. I am not a person who goes to the dealer but in this case I will but advise them that no work should be performed outside of what the warranty will cover. Really appreciate the advice from the mechanic and if this is the case and fixes my issue I have a bottle of wine with his name on it.

mr