What Causes a Lean Air-Fuel Mixture in Cars?
2 Answers
Here are the reasons for a lean air-fuel mixture in cars: 1. Insufficient fuel injection due to inaccurate detection of intake air volume by various intake sensors. 2. Excessive carbon buildup absorbing injected fuel. 3. Failure of the oxygen sensor's closed-loop control. Here is relevant information about lean air-fuel mixtures: 1. When the mixture is too lean, the combustion speed decreases, causing some mixture to burn while the piston moves toward bottom dead center. 2. A lean mixture results in higher idle speed, making it difficult for the engine RPM to drop to idle speed quickly when decelerating. 3. Removing the spark plugs will reveal white-colored electrodes, confirming an excessively lean combustible mixture.
When the air-fuel mixture is too lean, it usually indicates too much air and too little fuel, which can cause engine shaking and poor acceleration. Having driven for several years, I've encountered similar issues, with the most common being intake manifold leaks. After a few years of use, rubber hoses can age and crack, allowing air to seep into the system. Secondly, clogged fuel injectors are another cause—when there are impurities in the gasoline, the injectors can't spray enough fuel. Then there are sensors; for example, if the mass airflow sensor is faulty, it will inaccurately report the air volume, resulting in a lean mixture. Other issues like vacuum leaks or a weak fuel pump can also cause trouble. Once the mixture becomes too lean, the car not only consumes more fuel but also loses power, and in severe cases, the engine can overheat and sustain damage. I've found that promptly checking for leaks and cleaning the fuel system can resolve the issue—don't delay too long, or repairs will become more complicated. Regular inspections of the intake manifold and fuel filter can nip problems in the bud.
