Diesel Woes: Black Smoke & Cold Start Issues in EX

I have some experience with diesel engines, and I dealt with very similar issues on my 2013 Infiniti FX diesel last year (their QX70 nowadays). The symptoms were exactly like yours black smoke, hard starts, and that annoying glow plug light. Took it to my regular workshop, and yep, it was a faulty glow plug. They found one completely worn out plug that was messing up the whole starting sequence. Had it replaced, along with the other plugs as preventive maintenance (they usually wear out around the same time). Total bill was about 560 Euro, and it fixed everything no more smoke, starts perfectly now. Could you share your mileage and whether you've had any previous glow plug replacements? Also, have you noticed any warning lights besides the glow plug indicator? Might help narrow things down further. PS. Actually had a QX50 (EX's successor) a few years back these Infinitis are solid cars, just need to stay on top of maintenance.

Thanks. Yeah, I'm at 173518 KM and had my last service about 3 months ago. No other warning lights showing up besides the glow plug, which is a bit reassuring I guess. Haven't replaced any glow plugs before probably should've done it earlier as preventive maintenance like you did. Your experience sounds exactly like what I'm dealing with. €560 isn't too bad if it sorts everything out. Did they do the work in one day? Might give my local shop a call tomorrow and see if they can check it out. Thanks for sharing your experience really helpful!

Hey again! Yeah glad I could help! Just to follow up on your question the whole job took about 4-5 hours at my shop. They got it done the same day I dropped it off. Make sure to mention all the symptoms when you call them the black smoke, starting issues, and the DPF stuff. In my case, they actually found that the faulty plug had been causing incomplete combustion, which was why the DPF wasn't regenerating properly. After the fix, my fuel economy improved quite a bit too went from burning about 9.5L/100km back down to around 7.5L/100km. Your mileage (173k) is pretty similar to what mine was when I had the issue (around 165k). Quick tip when they replace the plugs, ask them to check the glow plug control module too. Mine was fine, but the mechanic said they sometimes go bad along with the plugs. Better to check while they're in there. Let us know how it goes after you get it sorted! These Infinitis are great cars when everything's working right.

Thanks a lot for all the detailed info! Really appreciate you mentioning the glow plug control module definitely wouldn't have thought to ask about that. Good to know about the timeframe too I'll try to schedule it for a morning appointment so I can get it back the same day. Your fuel consumption numbers are encouraging. I've been burning through fuel like crazy lately, so it'll be nice to get back to normal figures. I'll make sure to mention everything to the mechanic tomorrow and get them to do a thorough check while they're at it. Thanks again for all your help you've made me feel a lot more confident about what I'm dealing with. I'll update the thread once I've had it fixed!