Why is it difficult to drive when starting a cold engine?

[DiMatthew]

Engine, fuel, and lubricant temperatures are all insufficient. In low-temperature conditions, fuel atomization is poor, requiring higher ignition energy. After prolonged use, the spark plug's ignition gap tends to widen, leading to reduced ignition energy, which affects performance. The reasons for difficult cold starts are as follows: 1. Low engine temperature: The temperature inside the engine is insufficient, and both fuel and lubricant temperatures are low. Therefore, during a cold start, more fuel needs to be injected to meet performance requirements. Poor fuel atomization at low temperatures results in reduced ignition energy, affecting performance and causing engine shaking. Aging ignition coils, worn high-voltage wires, or leakage in spark plugs can also lead to decreased ignition energy. 2. Excessive carbon buildup on valves and intake ports causing difficulty in cold starts: Carbon deposits can absorb a certain amount of fuel, leading to incorrect ECU judgments. For example, if the computer controls the injection of 100 units of fuel-air mixture, but only 90 units actually enter the cylinder (10 units absorbed by carbon deposits), even if the remaining 90 units burn completely, it still won't meet the required performance.