BMW 1 Series Diesel: Power Loss & Rough Running Mystery

Hey there! I had a similar issue with my 2015 BMW 2 Series diesel last year. I've got some experience working on cars, but this was beyond my DIY skills. My car showed pretty much the same symptoms, drop in power, rough running, and that dreaded check engine light. Turned out one of the injectors was faulty. Took it to my regular workshop and they diagnosed it with their diagnostic tool. They had to replace the defective injector, which set me back about 515 Euro, but it fixed all the issues completely. Before I can help more specifically, could you share: Have you scanned for error codes? Does it smoke more than usual? Does the problem get worse when the engine is warm or cold? BTW, my cousin has a BMW 3 series and had similar problems, so these issues aren't uncommon on these engines. Hope this helps! Let me know those details and I might be able to share more specific advice.

Thanks for your reply! My car has 48451 KM on the clock and had its last service 3 months ago. Yeah, I've noticed blue smoke from the exhaust, especially when starting up cold. Haven't managed to get the error codes yet, but the problem definitely gets worse once the engine's warmed up. The jerking and power loss become really noticeable after about 10 minutes of driving. The fact that your issue was fixed with an injector replacement gives me hope. Did you notice any warning signs before it got really bad? I'm wondering if I should've caught this earlier. Good to know these aren't uncommon issues, though that's not exactly comforting for my wallet! Would you mind sharing which diagnostic tool your mechanic used? Want to make sure my mechanic uses something reliable.

Hey again! Yeah, looking at your symptoms, it's sounding more and more like what I dealt with. Before my injector completely failed, I did notice some warning signs, started with slight hesitation during acceleration, then gradually got worse over about 2-3 weeks. The blue smoke you're mentioning is exactly what I experienced too. Wish I'd acted sooner, honestly! My mechanic used a BMW-specific diagnostic tool, can't remember the exact model, but it was one of those professional-grade ones that cost thousands. They showed me the readings, and the fuel pressure was all over the place. Just avoid those cheap generic scanners, they might pick up the basic fault codes but won't give you the detailed info needed for these injection issues. Since you mentioned the cold start smoke and it getting worse when warm, it's really pointing towards an injector problem. Mine started at around 52000 KM, so your mileage fits the pattern too. The 3-month-old service probably wouldn't have caught this as these issues can develop pretty quickly. Pro tip: keep all your repair documentation. When I had mine fixed, the mechanic mentioned these injectors sometimes need recalibration after replacement. Had to go back once to get it perfectly sorted, but they did it under warranty since it was part of the original repair. Let me know what your mechanic finds. Would be interesting to see if it's the same issue!

Thanks so much for all the detailed info! This has been super helpful. Just called my mechanic and booked the car in for tomorrow morning. I mentioned the injector possibility and he seemed to think that's a likely culprit too. He confirmed they use proper BMW diagnostic equipment, so that's reassuring. You're right about acting sooner, I probably should've taken it in when I first noticed the slight hesitation. Lesson learned! Thanks for the tip about keeping the documentation too. I'll definitely make sure to get everything in writing, especially if there's a chance it'll need recalibration. Really appreciate you taking the time to share your experience. It's made me feel a lot more confident about what I'm dealing with. I'll probably end up out of pocket, but at least I won't be going in completely blind. Will update you once I know what the actual problem is! Thanks again for all your help!