Audi S4 Fuel Pump Failure Symptoms + Repair Tips

Working as a mechanic, I encountered nearly identical symptoms on my 2016 Audi A4 TDI. The automotive diagnosis revealed several potential failure points common to VAG diesel engines. The main issue causing engine stalling turned out to be a failing high-pressure fuel pump, combined with contaminated fuel injectors. The car performance gradually worsened until complete failure, showing similar symptoms: rough idle, increased fuel consumption, and intermittent stalling. Based on your description, I strongly advise against driving the vehicle. The risk of complete fuel system failure while driving is significant. Having a professional inspection is crucial, as a faulty fuel pump can cause cascading damage to injectors and other fuel system components. Key points to discuss with your mechanic: High-pressure fuel pump testing, Fuel injector diagnostic scan, Fuel pressure readings at idle, Fuel filter inspection, Electrical connection integrity check This repair was substantial, requiring specialized diagnostic equipment and expertise. With these symptoms, temporary fixes typically lead to more extensive damage later. Request a complete fuel system diagnostic before authorizing repairs. For immediate needs, professional towing is safer than attempting to drive the vehicle.

Thanks for the detailed insight. This matches perfectly with what I am experiencing with my S4. The fuel pump failure signs are exactly what you described, especially the rough idle and increased consumption. After getting burned by my previous auto repair experience, your response gives me confidence in what to look for. Did you remember roughly what the fuel pump repair ended up costing? Also curious if you had any lingering issues after the fix or if it completely resolved the problems? Trying to budget appropriately since it sounds like a major repair job.

After taking the car to a mechanic for automotive diagnosis, the issue turned out to be much simpler than expected. The fuel pump itself was actually fine, there was just a faulty cable connection causing the pump failure symptoms. The repair only cost 95 Euro to fix the loose plug connection. Since having this minor electrical repair done, the car performance returned completely to normal. The rough idle, stalling, and high fuel consumption issues disappeared immediately. This was quite a relief since a full fuel pump replacement would have been significantly more expensive. This shows how important proper diagnostic testing is before jumping to major repairs. A thorough inspection by a qualified mechanic revealed the true cause rather than just replacing parts. The car has been running perfectly for several months now with no lingering issues. Good thing we caught it early before any damage occurred to other fuel system components. Having dealt with similar symptoms, I understand the worry about potential repair costs, but sometimes the fix can be surprisingly straightforward.

I really appreciate everyone's input on my fuel system concerns. After getting your advice, I had the car towed to a reputable auto repair shop rather than risking driving it. Smart move, as it turned out. The mechanic found two issues causing my problems. The main culprit was a clogged fuel filter, and there was also a minor electrical connection problem with the fuel pump wiring. Total repair came to 280 Euro, much better than I feared given the symptoms. Car performance is back to normal now. No more stalling, rough idle is gone, and fuel consumption returned to standard levels. The mechanic also did a full system check to confirm no additional damage occurred. Looking back, I was overly worried about another bad repair experience, but having clear guidance on what to check helped me communicate better with the shop. Definitely learned my lesson about addressing these issues quickly before they can cause bigger problems.