Why Does the Car Shake When Starting Cold?
1 Answers
Cold start shaking is caused by insufficient engine temperature, inaccurate air-fuel mixture ratio, carbon buildup in the car, and other reasons. It is recommended that the owner promptly take the vehicle to a repair shop for inspection. Below are more detailed explanations: Detailed reasons: 1. During a cold start, the car should inject more fuel to meet power requirements. The larger the spark plug gap, the smaller the ignition energy. At low temperatures, fuel atomization is poor, requiring higher ignition energy. Over time, the spark plug's ignition gap tends to increase, leading to reduced ignition energy, which affects performance and causes the car to shake. 2. Inaccurate air-fuel mixture ratio occurs in both open-loop and closed-loop control. If the car's computer makes an error in judgment, it may cause inaccuracies in controlling the air-fuel mixture and ignition timing through the actuators, thereby reducing the car's power output and causing shaking. 3. When the car starts cold in the morning, engine shaking may be due to heavy carbon buildup on the valves, though faults in the air flow meter and coolant temperature sensor cannot be ruled out. If there is significant carbon buildup on the valves, the hardened carbon during cold starts can affect valve closure, reducing the engine's compression ratio and disrupting normal operation. During warm operation, the high temperature softens the carbon, preventing it from affecting valve closure, so the engine operates normally when warm.
