VW Golf TDI Fuel Problems: Pump Failure Warning Signs

I had a very similar issue with my 2003 VW Bora TDI, and as someone with some experience in car mechanics, I can share my troubleshooting journey. The symptoms you describe match what I experienced, engine stalling, rough idle, and increased fuel consumption. Initially, I also thought it was the fuel pump, but after taking it to my workshop, they discovered the actual cause was much simpler and less expensive. The problem turned out to be a faulty wiring connection to the fuel injector sensor. The repair involved replacing and properly securing the loose connection, which cost 95€ including diagnostic time. After the fix, car performance returned to normal immediately. However, these symptoms can have multiple causes in TDI engines. To provide more specific guidance, could you share: Any diagnostic codes from the check engine light, Whether the issues occur more when the engine is cold or warm, If you notice any black smoke from the exhaust, When was your last fuel filter change This information would help determine if your case is similar to what I experienced or if you might be dealing with a different fuel delivery issue.

Thanks for sharing your experience. At my last service at 28486km they checked everything, but the issue started shortly after. I pulled the diagnostic codes and got P0087 (Fuel Rail/System Pressure Too Low) and P0191 (Fuel Rail Pressure Sensor Circuit Range/Performance). No black smoke visible, but the problem is definitely worse when the engine is cold. These codes seem to point more directly to a fuel pump failure rather than just a wiring issue. I scheduled an automotive diagnosis appointment for next week, but wondering if anyone else can confirm if these specific codes typically indicate pump replacement is needed? Want to be prepared for potential repair costs.

Given your diagnostic codes, I need to revise my initial assessment. My Bora TDI later developed the exact same codes, and unlike the first wiring issue I mentioned, this turned out to be a genuine fuel pump failure. The repair involved replacing the complete high-pressure fuel pump unit. Total cost was around 850€ including parts and labor. While expensive, its worth noting that fuel pump replacement solved all symptoms permanently, restored proper fuel delivery, eliminated rough running, and brought fuel consumption back to normal. A few tips from my experience: Make sure they check the fuel lines and injectors while the system is open, Request cleaning of the fuel tank to prevent debris from damaging the new pump, Consider replacing the fuel filter at the same time Those specific error codes combined with cold start issues are classic signs of pump failure in these TDI engines. The car mechanics I dealt with explained that its a common wear point in the fuel delivery system, especially at that mileage range. Just to be thorough, have you noticed any metallic sounds from the engine bay? This could help confirm if the pump bearings are failing.

The diagnostic codes definitely seem more serious than the wiring issue you encountered. P0087 and P0191 together strongly suggest a fuel system pressure problem, which aligns with my initial fuel pump concerns. No metallic sounds from the engine bay yet, but the cold start problems have gotten worse over the past week. Based on your experience with the complete pump replacement, I should probably set aside around 900€ for the repair. The suggestion about cleaning the fuel tank and replacing filters while the system is open makes a lot of sense, no point risking debris contamination with a new pump. My pump is likely showing the same wear patterns you mentioned, especially since these issues started right after reaching similar mileage. I will ask the workshop to perform a thorough fuel system inspection when I bring it in next week, including checking the fuel lines and injectors as you suggested. One last question, after your fuel pump repair, how quickly did you notice improvements in fuel consumption and cold start performance? Just want to know what to expect if I end up needing the same fix.