Peugeot 208 Emissions Fail – Running Rich Explained!

Follow-Up & Context: This is a follow-up to my previous video where my Peugeot 208 (1.0L / 1.2L petrol engines) failed its emissions test due to an oil issue. After fixing the oil problem, I went for a retest – and it failed the emissions test again! This time, the culprit is a running rich condition. In this video, I share the journey of diagnosing why my Peugeot 208 is running rich (too much fuel in the mix) and how I plan to fix it. If you’re dealing with a Peugeot 208 emissions fail or similar running rich petrol engine problems, this might help you out. What Does “Running Rich” Mean? Running rich means the engine’s air-fuel mixture has too much fuel and not enough air. In other words, the combustion is fuel-heavy (rich mixture). This causes incomplete burning of fuel, leading to higher emissions of pollutants like carbon monoxide (CO) and unburnt hydrocarbons (HC). You might notice symptoms like a strong gasoline smell from the exhaust, black smoke, or even soot on spark plugs when an engine is running rich. In my case, the rich mixture caused the Peugeot 208 to produce high emission readings, which is why it failed the test. Running rich can also hurt your fuel economy and performance because the engine isn’t running at the optimal air-fuel ratio. Diagnosing a Running Rich Engine In the video, I walk through how to diagnose a running rich condition step by step on my Peugeot 208. I share the tools and approach I used as a DIY enthusiast to figure out what’s causing the rich mixture. Some common things I checked include: • O2 Sensor: A faulty oxygen sensor can send wrong signals, making the ECU add more fuel than needed. • MAF Sensor: A dirty or bad mass airflow sensor might misread incoming air and cause an overly rich fuel mix. • Fuel System: Leaking fuel injectors or a bad fuel pressure regulator can dump excess fuel into the engine. • Engine Temp: A stuck-open thermostat or bad coolant temperature sensor can trick the car into thinking the engine is cold, keeping the mixture rich. I also used an OBD-II scanner to read any fault codes (like a P0172 code for rich mixture) and looked at fuel trim data to see how the engine’s computer was adjusting the fuel. These diagnostic steps show how to diagnose running rich issues in a petrol engine so you know where to look if your car runs into a similar problem. Peugeot 208 Problems & Next Steps Peugeot 208 problems like this can be tricky (and a bit frustrating!), but I’m learning a lot through the process. After identifying that the engine is running rich, I discuss what I’ll do next to fix it so the car can finally pass the emissions test. The fix might involve cleaning or replacing a sensor, checking the injectors, or ensuring the ECU gets the right information to balance the fuel-air mix. Whether you have the 1.0L or 1.2L petrol version, the troubleshooting process in this video can help with similar Peugeot 208 issues. I hope sharing my experience will help fellow DIYers diagnose and solve their car’s running rich problems. It’s been a journey, but I’m not giving up on getting my 208 running clean! 😊 Disclaimer: This video is for educational and entertainment purposes only. I’m not a professional mechanic—just a DIY car enthusiast sharing my personal experience. Always consult a qualified mechanic for professional advice and proper repair of your vehicle. Thanks for watching and following along with my Peugeot repair journey! Tags: #Peugeot208 #RunningRich #CarRepair