[kctim]

Hey all, I have a weird one for you! I just got home after a long drive from getting my AMS FMIC, new spark plugs, and CDV delete installed on my car. Car is a 2009 335i Coupe, 30k miles, kept up with maintenance etc, HKS exhaust, Cobb Stage 1 Sport, and the mods I just got installed. Car has always ran great. I understand that it may be purely coincidence that the car started doing this within 30 minutes of a FMIC install.

On with the mystery.. I get home after my install and upon walking around the vehicle I noticed soot all over my bumper, and both exhaust tips covered.. Inside the exhaust tips I could see some sort of whitish or maybe brown tinted powder. The soot on the bumper reminded me of my last catless car, but I haven't touched my downpipes on this car. A quick swipe of a microfiber showed dark color with a quick swipe... but hey when does a microfiber NOT yield black when you wipe the rear end of a e92. I thought it may be something related to the FMIC install, because my car was never dirty around the exhausts and never any soot before hand on my bumper... at all.

I started the car, checked my cobb for any codes... no codes. I had my brother rev it a little to see if I could see smoke, none! But I did see ( might have been my imagination) a tiny flake of something, I repeated it a few times and it was clear. I called the shop that did the installation, my local BMW dealership, and a couple of the big name shops on this forum and we couldn't come up with many ideas as to what it could be. So, I decided it was ok to drive it again, mainly just curious if it would do it again. I wiped my bumper clean and drove 3 miles. I got on my car, first time flooring it since the FMIC install, and it felt great... I thought "ahh maybe something got in the fmic or in a pipe during install", maybe it'll blow/work it's way out of the piping. I kept checking my rear view, no smoke at all. As I pulled into my garage, I left car on, and noticed the entire back-end had soot all over it and I want to say the exhaust smelled .....differently, not rotten eggs, maybe a tad sweet but that could also be my imagination. It literally looked like I had driven catless for about a year without washing my car.

What I hope is I have a cat that's starting to go, but wouldn't it accumulate on one side of the exhaust more than the other? Both wouldn't fail at the same time, correct? I also noticed what first looked like white powdery substance is now more brown color. And how is it accumulating on my back end so much without me seeing any visible smoke??

It seems odd this started to happen right after a FMIC install, none of this adds up. The car is still under warranty, so that's a plus. Here are a few pictures... looks like your typical catless FILM but I assure you it's not, and the 2nd time I drove the car there was twice this amount.







Any suggestions, ideas, or help would be greatly appreciated!

[E90Company]

The flakes you say you saw, and the sweet smelling exhaust (coolant burning smells sweet) dousn't sound too good. Was this intercooler used? Did you bring it to a reputable shop to do this work? You have an HKS exhaust so your only cats are in the downpipes.

How does the car feel on power? Any strange noises such as clicking/knocking/lifter sounds? If something was in the piping, it dousn't simply "work it's way out of the piping". Whatever was in it goes through your motor (and turbos)..

[Jeff@TopGearSolutions]

I was going to say coolant smells sweet... I would have assumed from the picture you are running catless or insanely rich.

What do your logs show for AFR?

[kctim]

It's a brand new AMS FMIC, and the installer is very reputable in my area.

The power is there, and I can immediately feel the jump in power after the FMIC install.

I "think" I notice a light crackling noise somewhere in middle of the exhaust piping, but it may have always been there, it doesn't sound bad and I haven't listened/inspected the car inside of a garage as much as I have today, so I really wouldn't know what is "normal" sounding for this exhaust. It's very, almost undetectably faint sound though.

I say sweet smelling exhaust, but then again I suppose I never smelled my exhaust like this before..never had a reason too. My garage just had a faint different smell to it. I do know that it doesn't smell like a catless WRX, that was a much stronger noticeable smell.

[kctim]

I haven't checked any logs, I'm not comfortable driving the car because we've already used up our two free tows this year on the other car

I haven't flashed the car to stage 1 + fmic, would that possibly fix out fueling issues and maybe alleviate the issue. Of course, there are stock people that run a fmic without this soot accumulation issue so that wouldn't help would it.

[Mike@N54Tuning.com]

Check coolant level. Sweet smelling exhaust could be coolant.

Mike

[E90Company]

OK, I just wanted to see if you heard any obvious mechanical sounds, because the first thing that came to mind, was something in the intercooler getting sucked through the motor. Didn't see the pictures when I posted... I would log the car as soon as you can so we can see your AFR's. Make sure to tick bank 2 lambda in COBB's menu as well.

Question: What spark plugs did you use?

[kctim]

I used Bosch ZGR6STE2.

Isn't it strange for the car to be running rich without any changes to the tune though?? Also, isn't running rich lead to much stronger tones of black exhaust rather than a lighter color?

I'll post the log as soon as I can though, thanks for all the input guys.

[E90Company]

Originally Posted by kctim

I used Bosch ZGR6STE2.

Isn't it strange for the car to be running rich without any changes to the tune though?? Also, isn't running rich lead to much stronger tones of black exhaust rather than a lighter color?

I'll post the log as soon as I can though, thanks for all the input guys.

Could be a leaky injector/s, but can't be too sure. I would start with the logs and go from there.

[kctim]

Just wanted to conclude what was happening with my vehicle and thank everyone for their help and insight on this issue.

The logs showed AFR was around 13.5 when I first got on it at about 3500RPM and tapered to 12.2 at about 5800rpm. No timing was being pulled and everything looked healthy.

Today I took the car for a long drive back to the shop that installed my FMIC, and upon walking around the back of the vehicle.... no soot.. no exhaust film. The shop tech checked on a few things and told me everything looked fine, and that anything the lack of black around my exhaust tips might indicate I'm now running lean. I'm thinking, how can it go from going extremely rich to.. clean and lean.

He told me to run it hard and see how it acts for the next few days and if anything happens to bring it back.

I decided to call Cobb tuning on my car ride home to speak to them about this, mainly out of curiosity. He said that he has seen this before, but it's not very common. Apparently it's a combination of factors between the ROM type, where the car was originally sold, and the newly installed component. The stock fuel tables ( I believe he said at idle and startup), act differently from car to car and that sometimes the fueling is adjusted by the ecu rather aggressively until it is happy. That would explain why the car now appears to be back to normal, it just needed 20 or so miles of driving to stop the extremely rich conditions. Works for me!

I hope this thread saves someone else the panic I was going through for something so minor.

Thanks again for everyone's help. Now it's time to flash to the +fmic map and utilize the new fmic.

[Jeff@TopGearSolutions]

Originally Posted by kctim

Just wanted to conclude what was happening with my vehicle and thank everyone for their help and insight on this issue.

The logs showed AFR was around 13.5 when I first got on it at about 3500RPM and tapered to 12.2 at about 5800rpm. No timing was being pulled and everything looked healthy.

Today I took the car for a long drive back to the shop that installed my FMIC, and upon walking around the back of the vehicle.... no soot.. no exhaust film. The shop tech checked on a few things and told me everything looked fine, and that anything the lack of black around my exhaust tips might indicate I'm now running lean. I'm thinking, how can it go from going extremely rich to.. clean and lean.

He told me to run it hard and see how it acts for the next few days and if anything happens to bring it back.

I decided to call Cobb tuning on my car ride home to speak to them about this, mainly out of curiosity. He said that he has seen this before, but it's not very common. Apparently it's a combination of factors between the ROM type, where the car was originally sold, and the newly installed component. The stock fuel tables ( I believe he said at idle and startup), act differently from car to car and that sometimes the fueling is adjusted by the ecu rather aggressively until it is happy. That would explain why the car now appears to be back to normal, it just needed 20 or so miles of driving to stop the extremely rich conditions. Works for me!

I hope this thread saves someone else the panic I was going through for something so minor.

Thanks again for everyone's help. Now it's time to flash to the +fmic map and utilize the new fmic.

So it was just running rich and it adapted back to normal.

[kctim]

Yup. I still don't know what caused the "powdery" substance I saw, but it's not doing it anymore so I won't concern myself with it too much.

[E90Company]

Good deal!

[Mike@N54Tuning.com]

Glad its resolved for you..

Looks like Jeff got the diagnosis correct

Mike

[Jeff@TopGearSolutions]

Originally Posted by Mike@N54Tuning.com

Glad its resolved for you..

Looks like Jeff got the diagnosis correct

Mike

For once!