What Causes Difficult Cold Starts in Cars?
1 Answers
Difficult cold starts in cars can be attributed to the following reasons: 1. Faulty fuel pressure regulator: The fuel pressure in the fuel system directly affects the air-fuel mixture concentration. If the vehicle is hard to start, the fuel pressure should be checked first, and the fault location can be determined by inspecting the fuel pressure regulator. 2. Coolant temperature too low: When the coolant temperature is too low, the engine control unit (ECU) will increase the fuel injection volume based on the signal from the temperature sensor, commonly referred to as enriched starting. Due to the temperature, starting can also be difficult at this time. Therefore, it is necessary to replace the antifreeze timely according to climate changes. 3. Excessive carbon deposits: When there is too much carbon buildup 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 starts and making it difficult to start. Only when the carbon deposits are saturated with absorbed gasoline does the engine start more easily. 4. Faulty fuel injector: Injector faults are mostly evident in cold conditions. Especially in winter, the lower the engine temperature during a cold start, the greater the required increase in gasoline injection. This is mainly because, during low-temperature starts, gasoline vaporization near the intake valve and cylinder wall is poor, and some gasoline cannot fully evaporate and burn, leading to an overly lean air-fuel mixture in the cylinder. This results in difficult cold starts, unstable idling, and stalling. Once the engine warms up, these symptoms disappear.
