What are the reasons for a cold engine not starting?

[VonEmmanuel]

The reasons for a cold engine not starting: the cold start injector is not injecting fuel, coolant temperature sensor failure, intake sensor failure, poor injector atomization, intake pipe carbon buildup, spark plug failure, idle control valve failure, etc. If there is no strong gasoline smell from the exhaust pipe, it indicates a lack of fuel in the cylinders, which may be due to issues with the fuel pump, fuel lines, or fuel pump circuit. If the engine shuts down due to overheating protection after high water temperature, it is recommended to check the electric fan, clean the radiator, or inspect the water temperature sensor for faults. Poor quality fuel can also affect car starting. Inferior fuel often has poor volatility, especially in winter when temperatures are low. During cold starts, the engine block temperature is low, making fuel atomization difficult, which results in the fuel injected into the cylinders not mixing sufficiently with air, causing starting difficulties or even failure to start.