Mazda CX3 Diesel Issues: Black Smoke, Check Engine Light, Unusual Engine Cuts, and Starting Trouble

Hey there! I reckon I've been in very similar shoes as you are now. I used to have this similar issue with my 2020 Mazda CX5 Diesel. I'd class myself as having some hands-on car experience, you know, the typical weekend wrenching and stuff. When I faced these issues, I took my Mazda to a trusted local garage. After a thorough check, they told me my fuel filter heater wiring harness connector was damaged. It looks like you are on the right track with your guess. The cure cost me 110 Euro which was worth it to get old Bessie running smooth again. Before that, it was just like what you're experiencing now - black smoke, check engine light, the lot. Getting more info about your vehicle would be pretty useful to dig deeper, cause while these cars are friends, they're not best friends. Do you have any recent engine modification? What's your mileage reading currently? Hope that helps a bit, and good luck.

Hey! Thanks for your insight! You've given me a starting point to figure out this issue and it's comforting to know you've been through something similar. As for the mileage, my Mazda reads 139,648 KM on the odometer. I haven't done any recent engine modifications, she's stock as can be. And your experience with the fuel filter heater wiring harness connector sure sounds familiar, could be exactly what's going wrong here. I'll take her to my local workshop, get a full check just like you suggested, and cross my fingers it won't break the bank. Appreciate your help. I'll keep you posted on the progress. Cheers.

Hey again,, I'm glad to know my earlier experience could provide some directional insight. With your mileage reading and considering that you haven't done any engine modification, it's even more likely that your issue is linked to the fuel filter heater. Those symptoms you’re seeing are really familiar. And don't worry too much about the cost. It was a bother for me, yeah, but at least once the issue was sorted, my Mazda ran as good as new. So, taking her to a trusted local workshop for a full check is definitely a wise move. Looking forward to your updates. Please do let us know how it turns out. Fingers crossed, it'll be the same fix as mine was and your Mazda will be back on the road in no time! Good luck and keep us posted. Cheers!

Hey! You've been a great help, really appreciate your advice and experiences. I'll bring my Mazda in for a check as soon as possible. Your assurance calmed me down a tad, I was quite worried, to be honest. In the meantime, I've lined up a substitute car from a of mine until mine is back like a champ. Will definitely keep you informed about the whole journey. Thanks a bunch and catch you later. Cheers!