[cumorris]

Hey everyone, I have been trying to track down a problem with my 2011 BMW 335xi.

Brief overview:
I am currently having a misfire in Cylinder 1 going on that I can't seem to find the cause of, I was hoping some of the knowledgable guys here on the forum can help me out.

Relevant Current Modification List:
- JB4
- MHD Backend Flash
- Pure turbos Stage 1 Turbo
- NGK 97506 plugs
- Delphi coils
- 7" CTS FMI
- Injen CAI
- Catless Downpipe
- VRSF Charge Pipe
- PE Exhaust Mod

** Everything above but the JB4, charge pipe, CAI, and MHD were put / done about 1000 miles ago. The car also ran just fine after these mods for the last 1000 miles.

Car runs fine at stock boost levels, when I run map 1 or 2 it starts "shuttering" when boost increases, JB4 logs were showing a misfire in Cylinder 1.

I started by swapping the cylinder 1 and cylinder 2 ignition coil with each other. JB4 logs show misfire still in cylinder 1. I pulled the plug on cylinder 1 and it looked good, nothing directly obvious that I could see wrong with it. I went ahead and got a new spark plug and replaced cylinder 1's plug. It is running better after the swap but JB4 is still showing a misfire in cylinder 1 and it stutters frequently at higher boost still. I realized after the fact that I forgot to gap all the plugs when I put them in so they were at the factory gap, which appears to be about a 0.026.

Before I put the cylinder 1 plug back in I gapped it to 0.022 based on some recommendations on the forums. After looking around further, I found where others who are running E85 mixes and higher boost recommend 0.018 - 0.020. I am planning to pull all the plugs back out and gap them down to 0.020 as I plan to run an E85 mix once I get this issue figured out.

What I don't understand is why I am still having a misfire in cylinder 1, even with the new plug that is gapped properly? If that was the issue why did it only pop up now? The coils don't appear to be a problem since the misfire is staying in cylinder 1?

Does anyone have any recommendations on where to look next?
I will attach a JB4 log on map 2.

Thanks for any help!!

[HawkeyeGeoff]

Injectors would be my suggestion; wouldn't be the first time N55 injectors failed. Alternatively, you could throw some stock BMW plugs in there and see what happens.

[victorg95]

Originally Posted by cumorris

Hey everyone, I have been trying to track down a problem with my 2011 BMW 335xi.

Brief overview:
I am currently having a misfire in Cylinder 1 going on that I can't seem to find the cause of, I was hoping some of the knowledgable guys here on the forum can help me out.

Relevant Current Modification List:
- JB4
- MHD Backend Flash
- Pure turbos Stage 1 Turbo
- NGK 97506 plugs
- Delphi coils
- 7" CTS FMI
- Injen CAI
- Catless Downpipe
- VRSF Charge Pipe
- PE Exhaust Mod

** Everything above but the JB4, charge pipe, CAI, and MHD were put / done about 1000 miles ago. The car also ran just fine after these mods for the last 1000 miles.

Car runs fine at stock boost levels, when I run map 1 or 2 it starts "shuttering" when boost increases, JB4 logs were showing a misfire in Cylinder 1.

I started by swapping the cylinder 1 and cylinder 2 ignition coil with each other. JB4 logs show misfire still in cylinder 1. I pulled the plug on cylinder 1 and it looked good, nothing directly obvious that I could see wrong with it. I went ahead and got a new spark plug and replaced cylinder 1's plug. It is running better after the swap but JB4 is still showing a misfire in cylinder 1 and it stutters frequently at higher boost still. I realized after the fact that I forgot to gap all the plugs when I put them in so they were at the factory gap, which appears to be about a 0.026.

Before I put the cylinder 1 plug back in I gapped it to 0.022 based on some recommendations on the forums. After looking around further, I found where others who are running E85 mixes and higher boost recommend 0.018 - 0.020. I am planning to pull all the plugs back out and gap them down to 0.020 as I plan to run an E85 mix once I get this issue figured out.

What I don't understand is why I am still having a misfire in cylinder 1, even with the new plug that is gapped properly? If that was the issue why did it only pop up now? The coils don't appear to be a problem since the misfire is staying in cylinder 1?

Does anyone have any recommendations on where to look next?
I will attach a JB4 log on map 2.

Thanks for any help!!

How much power are you making on that setup?

[julian1999]

possibly injectors
do a compression test and a cylinder leakdown test as well

[The Silver Slammer]

More than likely its your plugs and or coils. I was chasing down similar issues, went with dealer plugs, factory gap and all misses went away. I would start with a new set of plugs, those NGK only last about 15-20k miles. Even less if run hard. Looks like you're not making target boost either. Possible a diverter valve issue or boost leak.