Can Replacing the Oxygen Sensor Save Fuel?
3 Answers
Replacing the oxygen sensor can save fuel, but the exact amount saved depends on the vehicle's condition and driving habits. The oxygen sensor's function is to monitor the vehicle's exhaust, detecting the oxygen content in the exhaust and then feeding the results back to the ECU. The ECU then uses this data to control the amount of air entering the cylinders and the fuel injection for the next cycle, ensuring complete fuel combustion and avoiding waste and pollutant production. However, if the oxygen sensor is faulty or has deteriorated due to prolonged use, the ECU cannot receive accurate data, leading to imprecise control of air intake and fuel injection, which results in fuel wastage. Oxygen sensors should be inspected and replaced approximately every 100,000 kilometers.
Once I noticed my car suddenly became extremely fuel-thirsty with black smoke from the exhaust. The mechanic said the rear oxygen sensor was faulty. After replacement, fuel consumption indeed returned to normal. The oxygen sensor acts like the 'nose' of a car's exhaust system, specifically detecting oxygen levels in emissions. If it fails, the ECU won't know how to adjust the air-fuel ratio - either wasting fuel with excessive supply or causing power loss with insufficient mixture. It's recommended to inspect this component around 100,000km, especially for older vehicles prone to contact point aging. As a reminder, exhaust modifications may also affect the sensor's data reading accuracy.
My pickup truck's fuel consumption suddenly increased from 8L/100km to 12L/100km recently. After troubleshooting for a long time, I finally found out that the upstream oxygen sensor was poisoned and failed. The fuel consumption dropped by more than 1L on the very day I replaced it, and completely returned to normal after two weeks. This thing has a much greater impact on fuel consumption than imagined, especially for direct injection engines which are more sensitive to air-fuel ratio. Using low-quality gasoline can accelerate sulfur poisoning of the sensor's platinum electrodes. Although the OEM part costs over 700 yuan which really hurts, it's still cost-effective compared to saving 200 yuan on fuel every month. The maintenance manual says this component should be replaced at 80,000 km - turns out it's not just trying to trick people.
