M2 Fuel Smell and Stalling: EVAP System Warning Signs

Hey there! I had very similar symptoms on my 2015 BMW M4 last year. Initially thought it was something major, but it turned out to be a defective activated charcoal filter in the fuel tank ventilation system. Main symptoms were identical, fuel smell in cabin, stalling at idle, and CEL. Had it diagnosed at a different shop after my regular mechanic couldn't pinpoint the issue. The activated charcoal filter was completely clogged, blocking proper fuel tank ventilation. They replaced the filter and purge valve assembly, and all symptoms disappeared immediately. Not a serious issue if fixed promptly, but definitely needs attention as it can affect engine performance and fuel economy. Also, that fuel smell isn't something you want to ignore. My mechanic mentioned this is fairly common on direct-injection BMW engines after 100k km. He showed me the old filter, it was pretty nasty. Since the fix, the car's been running perfectly with no issues.

Thanks for sharing your experience! That's exactly what I was worried about. Good to hear it wasn't anything too major in your case. Quick question, do you remember roughly how much you paid for the repair? Also, has everything been running smooth since then, or have you noticed any other quirks? Been thinking about getting mine checked out but just trying to get an idea of what I'm walking into.

Hey again! Happy to help update you on the costs and how things have been running. I just got mine fixed last week and it was exactly what I suspected, the activated charcoal filter was toast. Total bill came to 275 € for parts and labor, which honestly wasn't as bad as I was fearing. And what a difference it's made! My M4 is running like a dream now, no more fuel smells, no stalling, and the check engine light is history. It's been about 8 days since the fix and I've put quite a few kilometers on it without a single problem. The mechanic mentioned it was a pretty standard job for these cars once they hit higher mileage. I'd definitely recommend getting yours checked out soon. The peace of mind alone is worth it, and it's better to tackle these things before they potentially cause other issues. Let me know if you end up getting it sorted, would be curious to hear if you had the same problem!

Thanks for all the details! I bit the bullet and took it to a new mechanic yesterday. You were spot on, it was the charcoal filter. Paid about 300€, which seems fair compared to what you mentioned. The fuel smell is completely gone now, and the car feels so much smoother at idle. The new mechanic was actually great. He took the time to show me the old filter and explained everything clearly. Such a relief compared to my last experience! He even gave the fuel system a good clean while he was at it. Really glad I asked here first, saved me from stressing about potentially bigger issues. The car's running perfectly now. Thanks again for sharing your experience, definitely helped me make the right call!