Audi S5 Diesel: Stalling and Smoke Points to Bad Injectors

Had similar symptoms on my 2016 Audi A6 TDI. Poor power delivery and fuel consumption issues pointed to a faulty fuel injection system. The problem was traced to corroded electrical connectors on the fuel injectors, causing inconsistent spray patterns and incomplete combustion. Performance deteriorated gradually over weeks until the engine began stalling at idle. Black smoke during acceleration was a clear sign of incorrect fuel delivery timing. This turned out to be a serious issue requiring prompt attention, as prolonged operation could damage other engine components. The fix involved: Complete inspection of the injection system, Replacement of damaged injector connectors, Testing and recalibration of injection timing, Cleaning of fuel system components After repairs, the engine regained proper power delivery and fuel consumption returned to normal. Maintenance records show this is a known issue requiring periodic inspection of injector connections, especially in high-mileage vehicles. For your S5, recommend having a diagnostic scan focused on the injection system and getting the fuel pressure tested. The symptoms strongly suggest either electrical connection issues or potential injector failures.

Thanks for sharing your experience with the injection system issues. My S5 had those exact symptoms last year, stalling, poor power delivery and high diesel consumption. Took it to a specialist who diagnosed faulty injectors causing the problems. Really interested to hear how much the repair cost you since these system issues can get expensive. Has everything been running smoothly since the fix or did you notice any other problems popping up? The fuel leak I had a few months after still makes me wonder if it was related.

Yes since taking the car to the mechanic the injection system fault was completely resolved. The repair bill came to 95 Euro which covered fixing a loose cable connection to one of the injectors. Much cheaper than expected, as it turned out the actual injectors were fine, just the electrical connection was defective. The diesel engine has been running perfectly since then with normal fuel consumption and proper power delivery. No more stalling or smoke issues. Regarding your fuel leak concern, injection system problems and fuel leaks can sometimes be connected, especially if the leak is near the injector seals or fuel lines. Worth having those seals checked during regular maintenance to prevent future issues. A thorough engine diagnostic scan would likely identify if your past leak was related to the injection repairs. The key is catching these issues early before they cause more extensive damage to the fuel delivery system.

Following up on what went down at the mechanic, turned out my fuel injection system needed serious work. The tech found corroded wiring and failing seals that were causing all those engine problems. Total repair came to 1200 Euro including parts and labor. Pretty steep but had to be done. The air-fuel mixture is spot on now. Engine performance is back to normal with proper power delivery and no more smoke. Fuel consumption dropped back to standard levels too. Really glad I got it checked when I did, as the mechanic mentioned leaving it could have led to bigger diesel engine issues down the line. That fuel leak I mentioned was actually related, turned out one of the injector seals had deteriorated. Getting everything sorted at once was the right call. The S5 has been running great for the past few months with no problems. Regular maintenance checks are scheduled to keep an eye on the injection system and prevent similar issues from coming back.