Black Smoke & Power Loss: QX Diesel Sensor Mystery

Hey there, I had very similar issues with my 2016 Infiniti Q50d last year. Those symptoms you're describing black smoke, hissing, power loss, and high fuel consumption are classic signs of a clogged DPF (Diesel Particulate Filter), not just a boost sensor. When I brought mine to the garage, they did a diagnostic and confirmed the DPF was about 85% blocked. They had to do a forced regeneration first, but that wasn't enough in my case. The filter needed a deep clean and recalibration of the ECU. The whole job took about two days, but it was worth it. Car's been running like new since then. If it's anything like what I experienced, it's a serious issue that needs proper attention. Don't wait too long running the car like this can cause more damage to other components. I'd recommend getting it checked at an Infiniti specialist rather than a general mechanic. Hope this helps!

Thanks! That's really helpful. I had a feeling it might be something bigger than just the boost sensor. Your experience sounds spot on with what I'm dealing with. Quick question do you remember roughly how much the whole job set you back? Also, has everything stayed smooth since the repair, or have you noticed any other issues popping up? Just trying to get an idea of what I'm in for.

Hey again! Happy to help update you on my experience! Just had the whole thing sorted actually turns out it was both issues. The boost pressure sensor was definitely faulty (got that fixed pretty quick), but the real troublemaker was indeed that clogged DPF, just like I suspected. The total damage came to €1,325.00 for the DPF cleaning and related work. Bit of a hit to the wallet, I know, but honestly, it was worth every cent. My Q50d's running absolutely brilliant now like a completely different car! No more black smoke, no weird noises, and the fuel consumption's back to normal. Since the repair (it's been about 3 months now), everything's been smooth sailing. No issues whatsoever. The power's all back, and she's purring like a kitten. Just make sure you go to someone who knows what they're doing with Infinitis makes all the difference in the world. Let me know if you need any other details about the repair. Happy to share more about my experience!

Thanks so much for all the detailed info! I bit the bullet and took it to the mechanic yesterday. You were absolutely right it was the DPF causing most of the trouble, along with a faulty boost sensor. Cost me around €1,400 total, pretty close to what you paid. Just picked up the car this afternoon and wow, what a difference! The black smoke's completely gone, no more hissing, and it's got all its power back. The mechanic I found was great too really knew his stuff about Infinitis. He even gave me some tips about preventing DPF issues in the future. Really appreciate you sharing your experience helped me make the right decision instead of putting it off and potentially causing more damage. Feels good to have the car running properly again! Thanks again for all your help!

I fitted a Diesel chip tuning kit 3 years ago, put the power and torque up 30 %. , But it turns out that on some occasions the chip over boosts and the engine boost sensor picks it up and puts the engine into limp mode . Easy fix is, turn engine off wait 15sec and restart.

It's important to be cautious with chip tuning, as it can lead to issues like overboosting, which you've experienced. While restarting the engine can temporarily resolve limp mode, it's crucial to address the root cause to prevent potential long-term damage. Consider consulting with a professional to recalibrate the tuning or check for any underlying issues. Let me know if you have any further questions or need more guidance!