What are the reasons that prevent an engine from starting?

[EdwardLee]

The reasons that prevent an engine from starting are: 1. Poor quality or substandard gasoline; 2. Faulty oxygen sensor; 3. Malfunctioning air flow sensor; 4. Spark plug carbon buildup; 5. Engine knocking; 6. Damaged water temperature sensor; 7. Engine misfire. The engine is the device that provides power to the vehicle, determining its power, fuel efficiency, stability, and environmental performance. The solutions for an engine that won't start are: 1. Replace with higher-grade gasoline; 2. Replace the oxygen sensor; 3. Replace the air flow sensor; 4. Clean the spark plugs; 5. Replace the engine; 6. Replace the water temperature sensor.