Land Rover Diesel: Black Smoke & Power Loss Mystery

Had similar issues with my 2013 Land Rover Range Rover Sport diesel (with 78k km) last summer. That whistling sound and black smoke combo is pretty telling, turned out to be the electrical bypass valve gone bad, affecting the turbo control. Got it diagnosed at my regular garage. The symptoms matched yours exactly, jerky performance, power drops, and that annoying whistle during acceleration. The stalling at idle was what really convinced my mechanic to check the bypass valve first. It was quite a serious issue since it was affecting the whole turbo system. Left unfixed, it could've led to bigger engine problems. The repair involved replacing the electrical bypass valve unit and recalibrating the ECU. Had to leave the car at the garage for two days. Since the fix, it's been running smooth, no more smoke, whistles, or power issues. Would definitely recommend getting it checked soon, as these symptoms usually don't improve on their own.

Thanks for sharing your experience! Sounds exactly like what I'm dealing with. Since you got it fixed, I'm thinking of going the same route. How much did the bypass valve replacement set you back, if you don't mind me asking? Also, curious if you've had any other issues pop up since the repair? Really helps to hear from someone who's been through this already!

Hey there! Happy to help with more details. After I got the electrical bypass valve fixed (which cost me 250.00 €), everything's been running like a charm. They also found and sorted out that boost pressure control position sensor issue you mentioned while they were at it, which was definitely part of the problem. Been about 8 months now since the repair, and honestly, my Range Rover Sport's been performing beautifully, no more of those scary symptoms we talked about. The black smoke's gone, no more weird whistling sounds, and the engine's running super smooth. It's like having a different car! What really matters is that I haven't had a single related issue since then. I'd say it was money well spent, especially considering how much worse (and more expensive) it could've gotten if left unfixed. Just make sure you get a trustworthy mechanic who knows their way around Land Rovers, that makes all the difference!

Update on my Discovery situation! Finally got it sorted at a mechanic who really knew his stuff. You were spot on about the bypass valve, that was exactly the culprit. Ended up costing me a bit more, around 300, but they did a thorough job and even spotted a few minor issues they fixed while they were at it. Can't believe what a difference it's made! My car's running like new again, no more black smoke, that annoying whistle is gone, and the engine's smooth as butter. The mechanic was super professional, walked me through everything they did, and even showed me the old parts to explain what went wrong. Really appreciate everyone's help here, especially sharing your experience with the same issue. Sometimes it takes someone else going through it first to give you the confidence to get it fixed properly. Been driving for a week now with zero problems, what a relief! Guess I've found my new go-to mechanic too. Thanks again for pointing me in the right direction!