BMW i3 Rail Pressure Sensor Causing Engine Trouble?

Hey there, I had nearly identical issues with my 2017 BMW i8 Hybrid last summer. The symptoms matched exactly what you're describing, power drops, rough idling, and RPM fluctuations. My check engine light was also illuminated. After diagnosing, it turned out the rail pressure sensor was indeed faulty. It's a fairly serious issue since it affects the entire fuel delivery system. The sensor wasn't reading correct fuel pressure, causing the engine management system to get confused. The repair involved replacing the pressure sensor and recalibrating the fuel system. I was without my car for two days at the shop. While it's not a complex fix, it's crucial to get it done promptly to prevent potential damage to other components. From my experience, I'd recommend having it checked asap by a certified BMW technician. The symptoms won't resolve themselves, and continuing to drive could lead to bigger problems.

Thanks so much for sharing your experience! This is super helpful since the symptoms match exactly what I'm dealing with. I'll definitely get it checked out ASAP by a certified tech. Do you mind telling me roughly how much you ended up paying for the repair? Also, has everything been running smoothly since the fix, or have you noticed any other issues pop up with the fuel system?

Hey again! Glad I could help with my previous response. Yes, I did get the rail pressure sensor issue fixed last summer, and it cost me 240€ in total, parts and labor included. Not too bad considering the headache it was causing! I'm happy to report that since getting it fixed, my i8 has been running like a dream. No more power loss, stalling, or RPM issues whatsoever. The fuel system's been working perfectly, and I haven't had any related problems pop up. Honestly, it was like getting a different car back from the shop, the difference was that noticeable! Looking back, getting it fixed promptly was definitely the right call. These hybrid systems are pretty sophisticated, and letting issues linger can lead to more expensive repairs down the road. Trust me, once you get it sorted, you'll notice the improvement straight away. Let me know how it goes with your repair!

Thanks for the follow-up! I actually just got back from the mechanic yesterday, and you were spot on about everything. The rail pressure sensor was indeed the culprit. I ended up paying a bit more than you did, around 300 for parts and labor, but honestly, it was worth every penny. Got my car running perfectly now, no more stalling, power loss, or crazy RPM jumps. The mechanic I found was great too. He explained everything clearly and even showed me the old sensor. It was pretty worn out, which explained all those problems I was having. Really glad I didn't wait any longer to get it fixed. The car feels so much smoother now, almost like when I first bought it. Thanks again for pushing me to get it checked out quickly, you saved me from potentially bigger headaches down the road!

Hi, my 535D, error: 003F31 DDE rail pressure sensor signal. Any ideas? We've replaced all sensors... checked connectors etc. No breaks or anything else. The target/actual values also match. I hope it's not the high-pressure pump Any ideas??

(Translated from German)

Start by checking the wiring harness for any signs of damage or corrosion, as this can sometimes cause intermittent issues even if the connectors appear fine. Also, ensure that the ground connections are secure and clean. If everything checks out, consider performing a fuel pressure test to verify the high-pressure pump's performance. Let me know how it goes or if you have any further questions!