BMW Z3 Exhaust Woes: Check Engine + Rough Running Issues

Hey there! I actually faced similar issues with my 2003 BMW Z4 last summer. The symptoms you're describing match exactly what I experienced, rough idle, CEL, and that distinct exhaust smell. After diagnosis, it turned out to be a failing Lambda sensor (oxygen sensor) combined with a cracked exhaust manifold. The Lambda sensor was completely dead, causing the engine to run rich and mess up the fuel mixture. Had both issues fixed at my garage, the sensor replacement was straightforward, but the manifold work was more complex and took a couple of days. These symptoms shouldn't be ignored as they can lead to catalytic converter damage if left unchecked. Not trying to scare you, but I'd get it checked soon. The Lambda sensor issue is pretty common on these older BMW straight-six engines. Hope this helps with your diagnosis. Good luck with the repairs.

Hey, thanks a lot for sharing your experience with the Lambda sensor and manifold problems. That really sounds similar to what I'm dealing with. Quick question, do you remember roughly how much you ended up paying for the repairs? Also, has everything been running smoothly since the fix, or have you noticed any other issues pop up? Just trying to get an idea of what I might be looking at cost-wise and if I should expect any related problems down the line.

Hey again! Happy to report some good news after my previous reply about the Lambda sensor troubles. I just got my Z4 back from the mechanic last week, and they confirmed it was indeed a faulty Lambda sensor, just like I suspected. The repair set me back 375 € but honestly, it was worth every penny. The car's running like a dream now, no more check engine light, smooth idle, and that annoying exhaust smell is completely gone. To answer your question about long-term reliability, it's been absolutely spot-on since the fix. The throttle response is crisp again, and the engine's purring like it should. I'd say if your symptoms are matching what I described, you're probably looking at a similar repair cost. My advice? Don't wait too long to get it fixed, these sensors can cause bigger problems if left unchecked. The best part is I'm not burning through fuel like before, so I'm probably making some of that money back already. Let me know how you get on with yours!

Thanks for the detailed follow-up! I actually just got back from the mechanic today. You were spot on, it was the Lambda sensor causing all the trouble. The final bill came to about 400 plus labor, which wasn't as bad as I feared. Got them to check the manifold too while they were at it, but thankfully that was all good. Took it for a test drive and what a difference! The engine's running super smooth now, no more funky smells, and the throttle response is back to normal. Really glad I didn't put this off any longer. The mechanic mentioned the same thing about potential catalytic converter damage, so I definitely dodged a bullet there. Thanks again for sharing your experience, it really helped me make the decision to get it checked out right away instead of waiting. Feels great to have my Z3 back in proper working order!

Hello Can you help Error code 180001 Catalyst output below limit value. Sincerely

(Translated from French)

The error code 180001 indicates that the catalytic converter's efficiency is below the required threshold. This could be due to a few reasons, such as a failing oxygen sensor, exhaust leaks, or the catalytic converter itself being damaged or clogged. Start by checking for any exhaust leaks and inspect the oxygen sensors for proper function. If these components are in good condition, the catalytic converter might need further inspection. It's important to address this issue promptly to avoid potential damage to the engine or increased emissions. Let me know how it goes or if you have any further questions!

What causes the error catalytic converter conversion and catalytic converter conversion 2 n52k with sport exhaust if relevant

(Translated from German)

The error related to catalytic converter conversion efficiency can be caused by several factors. Start by checking the oxygen sensors, as they play a crucial role in monitoring and adjusting the air-fuel mixture. A faulty sensor can lead to incorrect readings and trigger this error. Additionally, inspect for any exhaust leaks, as they can affect the sensor readings and catalytic converter performance. If these components are functioning correctly, the catalytic converter itself may be failing or clogged. Since you have a sport exhaust, ensure that it is compatible with your vehicle's emissions system. Let me know if you need further assistance or have any updates!