What Causes Difficulty in Cold Starting a Sedan?

[Leon]

Sedan cold starting difficulty is caused by: 1. Fuel pressure regulator failure; 2. Coolant temperature too low: When the coolant temperature is too low, the engine control unit will increase fuel injection based on signals from the temperature sensor; 3. Excessive carbon deposits: When there are too many carbon deposits inside the engine, the gasoline sprayed by the cold start injector will be largely absorbed by the carbon deposits, resulting in an overly lean air-fuel mixture during cold start; 4. Weak battery. During cold starts, because the lubricating oil has low temperature and high viscosity, sufficient power is required at the moment of starting. Besides the air-fuel mixture, the ignition system also directly affects engine performance. If the spark plug gap increases or the ignition coil voltage decreases, it will slow down flame propagation speed, causing the piston's work during cold start to fail to meet starting conditions, thus resulting in starting difficulty.