100% Free

No Scanner Needed

Carly logo

Lisavogel19

Black exhaust smoke, increased fuel consumption and check engine light in 2008 BMW 3 Series - suspected NOx storage catalytic converter

Poor fuel economy

|

Black smoke from exhaust on acceleration

|

Loss of engine power

|

Exhaust leak

|

Check engine light on

Yo guys! I've recently been struggling with a few strange things in my 2008 petrol 3 Series Bimmer. There is black smoke coming out of the exhaust when accelerating and the check engine light is also showing something. It also has a noticeable lack of power and the fuel costs are rising. I think it could be the NOx storage catalytic converter, which has exceeded its service life. Have you ever had similar problems? How did you get it under control? Please share your experiences from the workshop with me. Thank you in advance!

(Translated from German)

8 comment(s)


JonasSpeedster

Hi there, I've been through a similar problem with my 2010 petrol BMW 1 Series. I am by no means a car expert, but more of a "regular workshop visitor". In my case, it was the NOx catalytic converter, which was heavily loaded or aged. I had it checked at the garage and then had to dig deep into my pockets - it cost €1350. But without the replacement, the symptoms would have remained. Can you give me more information about your car (mileage, engine, etc.)? Then I might be able to tell you more. Greetings!

(Translated from German)

Lisavogel19 (Author)

Hey, thanks for your answer! Well, mine now has about 214780 km on the clock. Everything was fine at the last service, but that was a while ago. It seems that, like you, I'm probably going to get a not-so-pleasant bill from the garage🙄. It's annoying, but that's the way it is with older cars, isn't it? Best regards back!

(Translated from German)

Best Answer

JonasSpeedster

No problem, man! Seems like you're dealing with the same problem I had back then. With the mileage, it's definitely possible that your NOx catalytic converter is at the end of its rope. The symptoms certainly fit. Not nice to hear that the bill is probably going to be high again, but better to take care of it before it causes more serious damage, right? My advice: off to the garage and let the experts take a closer look. It may be annoying, but after that your Bimmer should be running smoothly again. Cheer up, you'll be fine! Best regards!

(Translated from German)

Lisavogel19 (Author)

Hey, thanks for your advice! I will definitely visit a garage. I just hope they fix it so that I can enjoy my Bimmer for a few more years. After all, it holds a lot of great memories. It's no fun, but you're right, I need to take care of it before it gets worse. Well then, I'll let you know how it goes. Have a nice day!

(Translated from German)

OlliB

With INPA and ISTA, the catalytic converter can be quickly programmed to "NEW" again, as there seems to be a "clock" that tells your car WHEN the catalytic converter has to be "full" - regardless of the actual load.

(Translated from German)

Dimo11

What is INPA or ISTA? I have no idea right now

(Translated from German)

CarlyMechanic

@Dimo11

What is INPA or ISTA? I have no idea right now

INPA and ISTA are diagnostic software tools used by BMW to troubleshoot and diagnose issues with their vehicles. INPA is more of a basic tool, while ISTA is more advanced and comprehensive. However, using these tools requires a certain level of technical knowledge and they are typically used by professional mechanics. If you're not familiar with these tools, it's best to let a professional handle it. Do you have any other questions?

Let our mechanics help you!

Car Brands
carly-logo

© 2025 Carly Solutions GmbH & Co. KG. All rights reserved