BMW 6 Diesel Problems: Cold Start & Power Loss Issues

Hey there! I have some experience working on cars and had a similar issue with my 2002 BMW 5 Series diesel. The symptoms you're describing sound very familiar! My 5 series was showing the exact same problems, rough idle, starting issues, and being thirsty on fuel. Took it to my workshop and turned out it was indeed a faulty cable connection to the fuel filter heater. Got it fixed for about 95 Euro, mainly labor costs for tracking down the issue and replacing the damaged wiring. The car's been running smoothly since then. Before suggesting anything specific though, could you share: Current mileage? Any other warning lights? When was the last fuel filter change? The solution might be similar to what I faced but those details would help confirm. The 6 Series is basically like a bigger cousin to my old 5, so they share quite a few components.

Thanks for your input! My odometer is at 134344 KM and just had a service two months ago. Currently seeing the engine warning light on the dash. The fuel filter was replaced during the last service. Had a bit of progress since posting, I noticed the warning light flickers more when the engine is cold. Could really be that heater cable you mentioned. Pretty relieved to hear it wasn't too pricey to fix in your case. Going to get it checked at the workshop this week. Are you still running your 5 series? How's it holding up after the repair?

Hey again! Still running my trusty 5 series and she's going strong! After that fuel filter heater cable fix I mentioned, it's been smooth sailing for about 18 months now, no cold start issues or any of those annoying symptoms coming back. That flickering warning light you're seeing in cold conditions really rings a bell, that's exactly what mine was doing! The intermittent nature of the warning light, especially during cold starts, was what helped my mechanic pinpoint the issue with the wiring. Since you mentioned getting your fuel filter changed recently, I'm even more convinced it's probably the same issue I had. Sometimes during filter replacement, the wiring can get a bit stressed or slightly damaged if not handled carefully. My mechanic actually showed me the worn-out section of the cable after he fixed mine. Just a heads up though, make sure your workshop checks the connector properly too, not just the cable. In my case, there was also some corrosion in the connector that needed cleaning. The whole job took about an hour and a half, and like I said, wasn't too harsh on the wallet. Keep us posted on what your workshop finds! Always interested to hear how these fixes turn out.

Thanks for sharing your experience! Just had one more chat with my mechanic and booked an appointment for tomorrow. Your descriptions really helped me explain the symptoms better to him. He seemed pretty confident it's the heater cable issue too, especially after I mentioned that flickering warning light detail. Good to hear your 5 series is still running strong after the fix! Always nice to know these old BMWs can keep going with proper maintenance. I'll definitely get back here with an update once the workshop has taken a look. Fingers crossed it's just the cable and connector like in your case, and nothing more serious. Really appreciate everyone's help on this. There's nothing like getting advice from who've actually dealt with the same issues firsthand.