A3 Fuel Injection Issues: Black Smoke and High Consumption

Had similar symptoms with an Audi A4 2017 petrol engine. The black smoke and high fuel consumption pointed directly to a faulty fuel injection system. After thorough diagnosis, the root cause was a damaged wiring harness connector at the fuel injector, which created inconsistent electrical signals. The repair involved replacing the entire injector wiring harness and reprogramming the engine control unit. This was a serious issue since faulty injection can damage other engine components if left untreated. The performance difference after repair was immediately noticeable, smooth idle, proper acceleration, and normal fuel consumption returned. The symptoms match your case, excessive fuel consumption, power loss, and black smoke are classic signs of injection system problems. The stalling indicates the engine management system is likely struggling to maintain proper fuel delivery. Worth checking the basic elements first: fuel filter and pressure regulator. However, given the mileage and symptoms, professional diagnostic testing of the entire fuel system would be recommended. These injection issues typically require specialized equipment to properly diagnose and repair.

Thanks for sharing your experience with the injection system failure. I had very similar problems with my Audi A3 last year, black smoke, terrible fuel economy, rough idle. The symptoms were spot on but in my case it turned out the air mass sensor was malfunctioning, leading to wrong air-fuel mixture readings. The maintenance was pretty straightforward once properly diagnosed. Did you remember roughly how much the wiring harness repair cost you? Also curious if you had any other injection-related issues pop up since getting it fixed. My repair happened about 8 months ago and everything is still running smoothly, but always good to know what to watch out for.

Similar story here with my A4, took it to a certified mechanic last month and the injection system fault was traced to a loose connector in the wiring. The performance difference is remarkable now that its fixed. Total repair cost was 95 Euro for replacing the faulty cable connection, which was causing erratic signals to the injection control unit. No other injection issues since the repair. The engine runs perfectly smooth with normal fuel consumption and proper power delivery under acceleration. The black smoke is completely gone too. These electrical connection problems can really impact engine performance if left unchecked, but once properly diagnosed and fixed, they typically stay resolved. Good to hear your air mass sensor repair worked out well. A properly functioning air-fuel mixture is crucial for diesel engines especially. Regular maintenance checks can help catch these issues before they develop into bigger problems that could affect overall engine performance.

Thanks everyone for the helpful input. I finally got the issue sorted with my A3. After reading about your experiences, I took it to a recommended specialist garage. The mechanic found multiple issues with the fuel delivery system, clogged injectors and a failing fuel pressure sensor were the main culprits. The repair cost me 380 Euro total, including parts and labor. The engine response is completely different now, smooth idle, proper power delivery, and my fuel consumption is back to normal. No more black smoke either. The air flows much better through the system since they cleaned everything up. Regular maintenance definitely could have prevented this. The technician showed me how carbon deposits had built up over time, affecting the entire fuel system. They recommended an injection cleaning service every 30000km to avoid similar issues in the future. Really glad I got it fixed before any serious engine damage occurred. The difference in performance makes it clear just how bad it had gotten. Would definitely recommend getting these symptoms checked out early rather than waiting like I did.