Audi A1 Running Rich: Common Causes and Fixes

Had the exact same symptoms on my Audi A3 (2012). Engine would run rich, terrible fuel economy, and that annoying jerking during acceleration. After some basic troubleshooting pointing to the fuel system, the workshop found one of the fuel injectors was defective, messing up the air-fuel ratio completely. The repair involved replacing the faulty injector and running diagnostics to ensure proper fuel delivery. Total cost was 515 Euro including parts and labor. Performance returned to normal immediately after the fix, and fuel consumption went back to expected levels. Worth noting that the oxygen sensor readings helped diagnose the issue, as it was showing the engine constantly running rich. The intake manifold was also checked but was clean. To better assist with your A1 issue, could you share: Current mileage, Any other warning lights besides check engine, When was the last time spark plugs were replaced, Any unusual sounds or smells from the exhaust These details would help determine if your symptoms point to the same root cause.

Thanks for checking my A1 issue. My mileage is currently at 140371 KM. The last full service was done 2 months ago with the air filter replacement, but the issues started appearing only last week. The exhaust has a strong fuel smell and seems to produce more black smoke than usual. No additional warning lights besides the check engine light have appeared. The spark plugs were replaced about 25000 KM ago during a routine maintenance. The air-fuel ratio issue seems quite similar to what you experienced. My current fuel economy has dropped by about 25%. Will get it checked at the workshop, focusing on the fuel injectors and oxygen sensor diagnostics first.

Thanks for the additional details. Those symptoms match what I experienced even more closely now, especially the black smoke and fuel smell from the exhaust. These are classic signs of a rich mixture condition, just like I had with my A3. Given your recent air filter replacement and relatively new spark plugs, those can likely be ruled out. The strong fuel smell and black exhaust strongly suggest either a stuck fuel injector or faulty oxygen sensor throwing off the air-fuel ratio. In my case, the check engine light codes pointed directly to the injector issue. The catalytic converter was also starting to get clogged from all the excess fuel, but luckily we caught it early enough before any damage occurred. Since your mileage is similar to what mine was when the injector failed (around 145000 KM), I would bet you are facing the same problem. The 25% increase in fuel consumption is almost identical to what I experienced. The repair should be straightforward, diagnostic scan, injector replacement if needed, and checking the oxygen sensor readings. Might want to have them inspect the catalytic converter condition while they are at it, given the rich running condition.

Based on your experience and feedback, I'm more confident now that my A1 has a similar fuel system issue. The matching symptoms of black smoke, fuel smell, and that 25% drop in fuel economy really point toward injector problems. I appreciate knowing the repair costs were around 515 Euro in your case. Will schedule a workshop visit this week and have them run diagnostics on the fuel injectors and oxygen sensor first. Smart suggestion about checking the catalytic converter too, definitely want to catch any issues early before more expensive problems develop. Just to ensure everything is properly documented for the workshop, I have noted down all symptoms: Rough idle and power loss, Check engine light, Poor fuel economy (25% increase in consumption), Black exhaust smoke, Strong fuel smell, Jerky acceleration, Engine running rich Will update the forum once I get the diagnostic results and repair completed. Hoping for a straightforward fix like in your case.