2019 Volvo V90 Exhibiting Fuel System Issues and Decreased Mileage

Hey there! I've got a 2016 Volvo S90, diesel engine, pretty close to what you're dealing with now. Last winter, my car started acting strange, almost identical to what you described: black smoke, weird exhaust smell, killing engine at idle, poor MPG, and of course, the dreaded check engine light. Would you believe, it turned out to be buggy cable connections? Just like you, my first guess was something with the fuel system. But my mechanic after giving it a full check-up found faulty cable connections causing inconsistent signals to several parts of the engine. Man, was that annoying! It was screwing up the info going into the engine control unit from sensors. This unbalanced the fuel-air mixture and messed up the combustion, leading to all those issues. Now I wouldn't say it was a ginormous-job-of-a-lifetime kind of serious, but it sure was significant. Because if not checked in time, it would have probably caused more serious damage to the engine down the road. The garage took care of it - they installed a new wiring harness and removed the bugs from the whole system. Work was a bit detailed but things have been smooth sailing since. That's my two cents. Do get your car to a trustworthy mechanic for a thorough diagnosis. And do ask about cable connections too. It might just save your day. Good luck!

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Hey there! Wow, sounds like you've been down a similar road with your S90. Buggy cable connections, who would've guessed it, huh? I was dead set on it being a fuel system issue, just goes to show that cars can throw some real curve balls at you. It definitely sounds like it was a pretty significant job though, and I'm glad you caught it in time before any major damage happened. Using a new wiring harness sounds like a sensible move. Do you happen to remember how much you had to cough up for the fix? I'm hoping to be prepared before I dive into this mess. And since you've had it repaired, has anything else cropped up or has she been behaving well? Appreciate your help.

(Translated from German)

Hey! Yeah, mending the buggy cable connections did tame the beast, at least for a bit there. I do remember having to shell out about 95€ for it. Not pocket change for sure, but definitely worth it to get old girl back to running smooth. Now, if memory serves, since addressing the cable issue there was this one problem. My low pressure fuel system sensor stopped functioning some time later. But after a quick trip to my trusty mechanic, that problem was fixed in no time and there hasn't been another issue since. So, all in all, the investment to fix the cables and subsequent sensor problem has seemed to pay off. My S90's been behaving better than ever! I can only hope your V90 gives you as little trouble as mine has since the repairs. Best of luck!

(Translated from German)

Hey! Thanks so much for the detailed response. Shelling out about 95 Euro, huh? While it's not small change, it definitely beats the cost to repair or replace an entire engine had things spiraled out of control. And hearing how well your S90 has been behaving since the fix, it certainly seems like a worthy investment. I'll make a note about the low pressure fuel system sensor too. It's helpful to know what I might run into post repair. Thanks again for the advice, I feel much more equipped to handle my issue now. Best of luck with your S90. Cheers!

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