What Causes Difficulty in Cold Starting a Car Engine?
2 Answers
Here are the specific reasons for difficulty in cold starting a car: 1. Excessive carbon deposits leading to frequent malfunctions. When there is too much carbon buildup inside the engine, the gasoline sprayed by the cold start injector can be largely absorbed by the carbon deposits, resulting in an overly lean air-fuel mixture during cold starts and making it difficult to start the engine. Only when the carbon deposits become saturated with gasoline does the engine start more easily. After starting, the gasoline adsorbed on the carbon deposits is then drawn into the combustion chamber by the engine's vacuum suction, making the air-fuel mixture too rich. This fluctuation between lean and rich mixtures causes the engine to idle roughly after a cold start. 2. Low engine temperature. When the engine temperature is too low, the fuel and lubricating oil do not reach the required temperature, so more fuel should be injected during cold starts to meet performance demands. Poor fuel atomization at low temperatures leads to reduced ignition energy, affecting performance and causing the car to shake. Aging ignition coils, spark plug high-voltage wires, or electrical leakage can also reduce ignition energy.
I've been repairing cars for over ten years and found that cold start difficulties are often caused by old batteries. In cold weather, the battery power drops quickly, making the ignition feel weak. Carbon buildup in the fuel injectors is also quite common, leading to poor fuel flow—the engine cranks but doesn't start. Worn spark plugs or faulty ignition coils can also cause unstable ignition. If the engine oil viscosity is too high, poor lubrication in cold conditions increases starting resistance. A dirty air filter can also restrict airflow, affecting combustion. It's recommended to regularly check the battery's health, switch to low-viscosity oil in winter, and keep the fuel system clean. Parking in a garage or heated area can reduce these issues.
