Why Won't a Hot Engine Start?

[DelPaige]

Here are the reasons why a hot engine won't start: 1. After the hot engine is turned off for a period of time, the temperature in the engine compartment remains high. If the fuel itself is highly volatile, it can easily form high vapor pressure in the fuel rail. When this pressure exceeds the pressure of the fuel supply system, it creates vapor lock, causing the fuel injector to spray excessively lean fuel vapor, making it difficult to start. 2. The fuel injector normally sprays fuel, but if it leaks, it provides additional fuel supply. The more severe the injector leakage, the richer the air-fuel mixture becomes, making it difficult to start a hot engine. 3. If the carbon canister purge valve is damaged, the fuel atomization during a hot start is already normal and doesn't require additional fuel vapor. However, if the carbon canister continues to supply fuel vapor to the intake manifold, it will result in an overly rich air-fuel mixture, making it difficult to start. 4. The intake air temperature sensor is similar to the coolant temperature sensor, as both are used to adjust the fuel injection quantity. However, if the coolant temperature sensor fails, it causes difficulty in cold starts, whereas a faulty intake air temperature sensor leads to difficulty in hot starts.