Seeking Advice on Dealing with Black Smoke, Engine Light, and Erratic Behavior in a 2018 Mercedes Viano Diesel

Hey there! Well, funnily enough, I've had a similar issue with my 2016 Mercedes Sprinter not too long ago. Rough idling, hiccuping, the works. Before we start, let me clarify I'm no professional mechanic, but I've got some experience under my belt dealing with car issues. Anyway, my issue turned out to be a defective fuel pressure regulator. Honestly, it was a pain trying to figure it out since there were so many symptoms, quite like what you're experiencing. Took the old girl to my local workshop and they were able to diagnose the problem. Ended up paying around 250 Euro to get it all sorted and she's running smooth as butter again. But, hold up, knowing your model isn't enough for me to give you proper advice. Could you give more info about the mileage, service history, any recent repairs or part replacements? There might be a pattern we could use to nail down the issue. Cheers!

Hi! Thanks for the feedback and taking the time to share your experience. My Viano's mileage is currently at 268478 KM. The last service check was about a month ago; they didn't mention any major issues then. While the previous owner did a part replacement on the clutch, I haven't done any big repairs or replacements under my watch. Any thoughts on what might be causing the trouble now?

Hey, no trouble at all! With that information, your suspicion about a fault in the mixture preparation might be on point. However, as you also have black smoke, stalling, jerking, and the check engine light is on, it might be more related to something in the fuel system. Based on your symptoms and what happened with my Sprinter, in particular, there could be a slew of underlying causes here: faulty injector, high-pressure fuel pump, or even a clogged filter/diesel particulate filter (DPF). A failing injector can cause a misfire and an unsteady mixture preparation which leads to power loss, black smoke, etc. On the other hand, a clogged DPF can also cause smoke and reduced power. The best advice I can give, as a fellow Mercedes owner who rolled up their sleeves once, would be to take your Viano to a trusted mechanic or workshop and ask them to run a full diagnostic. It'll be quicker and more accurate with their equipment and they could help pinpoint the culprit. It's frustrating, I know, but try not to worry too much. I hope you'll find the issue soon and get it sorted! Cheers and keep us updated on how it goes.

Hey, thanks a ton for such a detailed reply! Your assessment makes a lot of sense, and with black smoke, it's highly likely the issue lies somewhere in the fuel system. You know, when owning an older diesel engine, one should always look out for potential injector or DPF faults. I'll take your advice and head to my trusty mechanic for a full-on diagnostic, hoping this won't make a deep hole in my pocket. Anyway, fingers crossed! Appreciate the help, and I'll definitely keep everyone updated. Have a good one! Cheers.