Mazda 3 Diesel (2017) Emitting Black Smoke with Power Loss and Poor Fuel Economy - Seeking Advice on Diagnosis and Repair

Hey there, seems like you're pretty much in the same boat I was a month ago. I've got a Mazda 6 (2015 Diesel) myself and had symptoms identical to the ones you just mentioned. Now, mind you, I am by no means an automobile expert, but I hold some experience in dealing with these issues. Turned out in my case that the culprit was a bad Fuel pressure regulator. My car was guzzling up fuel like a post-workout bull and belching out black smoke, just like yours. I took my ride to my trusty local workshop. The guys there were able to diagnose the issue pretty quickly and told me that it was the fuel pressure regulator that was defective. It cost me around 250€ to get it fixed. I'm not sure if the pricing would be will be same for you, but just giving you a ballpark figure. Also, the workshop guys reminded me that this might not be the only cause, so it would probably be better if you went to your trusted mechanic or workshop, just to be on the safer side, you know? Can you share more details about your car, like its mileage, your driving habits, maintenance history etc.? That would be really great in helping me understand and assisting you further. Don't stress too much, I'm sure you'll get your Mazda sorted out soon! Cheers!

Hey, thanks for sharing your experience. It's reassuring to know I'm not the only one! In terms of mileage, my stubborn mule has covered a staggering 219,612 KM without any major glitches till now. I mostly use it for daily commuting, and occasional long drives for work. I've always stuck to the routine servicing as per the manufacturer's advice. I had its last service done about 6 months ago. I'll definitely get my mechanic to check that fuel pressure regulator you mentioned. Hopefully, it's nothing more serious. Fingers crossed! Cheers for the help.

No worries at all! With your usage and the kinda mileage you've clocked, it does sound like some wear and tear issues are bound to come up. The good news is, you've been regular with your servicing, and that's top-rate stuff! Now, based on your driving habits and the symptoms you described, it does indeed sound eerily similar to what I experienced. A faulty Fuel pressure regulator was my demon, and it might just be yours too. That being said, don't go jumping to conclusions. Stick to your plan and have your mechanic take a good hard look, who knows what he might find. Just remember, cars can be weird monsters, sometimes! The black smoke and reduced power could also indicate problems with your fuel injectors, or it could be something as simple as a blocked air filter. Whatever it is, just hang in there! Let’s hope it all works out cheaper and easier than you're expecting. Keep me posted about any updates. Happy motoring and fingers crossed for you!

Thanks for the vote of confidence! I do hope it's just wear and tear or something simple like you said. I've set up an appointment with my mechanic for tomorrow. Got my fingers crossed, hoping for the best! Will definitely keep you posted. Cheers for all the help and advice. You've lifted a major load off my mind. Happy motoring to you too!