What are the reasons for difficult cold engine starting?

[DeNicole]

Difficult cold engine starting can be attributed to the following reasons: 1. Poor fuel quality: Inferior fuel has poor volatility, especially in winter when it is difficult to atomize, resulting in insufficient mixing of fuel injected into the cylinder with air, leading to starting difficulties or even failure to start. 2. Excessive carbon deposits on valves and intake pipes causing cold starting issues: Carbon deposits can absorb an appropriate amount of fuel, leading to ECU misjudgment. For instance, if the computer controls the injection of 100 units of fuel-air mixture, but only 90 units actually enter the cylinder (with 10 units absorbed by carbon deposits), even if the remaining 90 units burn completely, the required power output cannot be achieved, inevitably causing shaking. 3. Excessive carbon deposits: Carbon deposits can negatively affect the normal operation of the engine. For example, excessive carbon deposits in the combustion chamber can increase the compression ratio, creating multiple hot spots that cause pre-ignition and detonation, shortening the engine's lifespan. Carbon deposits on the valve and its seat surfaces can prevent the valve from sealing properly, leading to air leakage, difficulty in starting the engine, reduced power, and increased valve erosion.