Mazda 3 Diesel 2020: Handling Issues with Black Smoke, Check Engine Light, and Jerking Acceleration

Hey! While I'm not a true petrolhead, I think I can help you out here with some experience from my 2018 Mazda CX-3 Diesel. Sounds like we shared the same problem. I was too facing a similar story from the jerking motion to the smoke and hisses coming from the car. Let me tell you you hit the nail right on the head - it turned out to be a wiring harness to boost pressure actuator problem for me. I spent 155€ in the workshop on this issue. My mechanic checked the diagnostic codes first. When he figured out it was the harness, he replaced it straight away. I was told it regulates the turbocharger's boost pressure and was damaged, causing my car to act funky just like yours. But to guarantee I'm right about this, I need to know if your car has any recent modifications or additional details on how it's behaving. Let me know, and I hope you fix your baby soon!

Cheers, Thank you so much for your quick response. I guess it probably is the wiring harness to the boost pressure actuator. No recent modifications all is still stock, I prefer it that way. The last service was at 61040 KM and no issues were reported then. To give a bit more insight about the behaviour, the jerk and hissing get worse whenever I'm going uphill, almost as if the car is straining to move forward. It's uncomfortable, not to mention embarrassing when people turn to look! I think I'm gonna book a garage appointment soon and will definitely suggest checking out the possibilities to the mechanic. Thanks again for sharing your experience and get back to you soon with updates. Cheers!

Howdy, Oh I exactly know how embarrassing it could be in public, been there done that! Based on what you've said (going uphill, and all that), we're mirroring each other’s situations over here. The uphill battle with your Mazda sounds similar to what my CX-3 would do. It's like you’re flooring it but the car feels like it’s dragging a massive load, isn't it? I bet this can be traced back to the faulty boost pressure control, just what like happened to mine. These issues normally sneak in post the 60,000 KM mark, so your car's history aligns as well. Throwing in another piece of advice; don't put off the workshop visit. It's better to have it checked earlier because in my case, the fuel economy was affected pretty bad and I ended up spending a chunk on that too. Let's hope it's nothing major for your Mazda. Stay positive and let's wait for what the mechanic says. And don't forget to update us here! Safe driving! Cheers!

Hiya, You've got it exactly right! Feels like I'm towing a boat or something. Spot on about the 60,000 KM mark too. Thanks for the advice, I won't wait around. Booked a garage visit for first thing Monday morning. that extra fuel cost is a sting I'd rather avoid. Feels like I'm filling her up way too often. I absolutely will keep you posted - cross your fingers for me that it's not a too major issue. I'm pretty hopeful after hearing from you. Thanks again, and I'll catch you up on the other side of this repair. Drive safe too! Cheers!