Civic Diesel: Black Smoke + Power Loss = Bad Boost Sensor?

Hey there! I have some experience working on diesel engines and had a very similar issue with my 2004 Honda Accord diesel back in the day. Based on your symptoms, it sounds a lot like what I dealt with, but it turned out to be a clogged DPF (Diesel Particulate Filter), not the boost sensor. I first blamed the boost sensor too, but my trusted mechanic diagnosed the real culprit. The repair included a complete DPF cleaning and system reset. Set me back about 1325€, but it solved all those symptoms, the black smoke, power loss, and jerking completely disappeared. Before we jump to conclusions though, How many miles/km on your Civic? Have you noticed decreased fuel efficiency? Any recent long-distance drives? This info would help confirm if you're facing the same DPF issue I had.

Thanks for your detailed response! My Civic's at 90967 KM and just had its service last month. You know what's interesting, I've definitely noticed the fuel efficiency dropping lately. Used to get way better mileage before these issues started. The DPF suggestion makes a lot of sense actually, especially with the black smoke. Haven't done many long drives recently, mostly short trips, which I've heard can be tough on the DPF. Might explain why it's not burning off the soot properly. 1325€ is quite a bit, but I guess it's better than letting it get worse. Did you try any DPF cleaners before going for the full service? Been thinking about trying those first, but not sure if it's worth the effort.

Hey again! Yep, after seeing your mileage and driving pattern, I'm even more convinced it's the DPF, exactly like what happened with my Accord. Those short trips are definitely not helping, as the DPF needs good heat cycles to regenerate properly. About the cleaners, honestly, I tried a couple of those fuel additives before going to the mechanic. Spent around 50€ on different brands, but they didn't really solve the problem. Just temporarily masked it. Looking back, I wish I'd gone straight for the proper cleaning instead of wasting time with those partial solutions. Quick tip from my experience, after getting it fixed, I started doing what my mechanic suggested: taking the car for a proper 20-minute highway run at least once a week. Really helps keep the DPF clean and prevents these issues from coming back. Been running smooth for over a year now! If your driving pattern is similar to what mine was (lots of short trips), you might want to skip the additives and go straight for the professional cleaning. Could save you money in the long run, especially if you catch it before the DPF gets completely clogged. Mine was pretty bad by the time I got it fixed, which is probably why it cost so much.

Thanks so much for all this great info! You've really helped me understand what's going on with my Civic. I think I'll skip those DPF cleaners, sounds like they'd just be throwing money away. Going to book it in with my mechanic next week for a proper DPF cleaning before things get worse. That weekly highway run tip is super helpful too. I can definitely work that into my routine, probably on my weekend grocery runs. Makes total sense about needing those longer drives to keep everything running properly. Really appreciate you sharing your experience. You've saved me from going down the wrong path with the boost sensor and probably saved me some cash too by catching this early. I'll update the thread once I get it sorted, might help someone else with similar issues!