What Causes the Starter Motor to Fail When the Engine is Hot but Starts Easily When Cold?

[ODeclan]

Difficulty starting a hot engine may be caused by fuel injector leakage, a faulty carbon canister purge valve, or fuel quality issues. Below are the reasons and solutions for hot engine starting difficulties: 1. Fuel injector leakage: While fuel injection is normal, leakage constitutes additional fuel supply. The more severe the injector leakage, the richer the air-fuel mixture becomes, leading to hard starting when the engine is hot. 2. Faulty carbon canister purge valve: During hot starts, fuel atomization is normally sufficient without requiring additional vapor. If the carbon canister continues supplying vapor to the intake tract, it creates an overly rich mixture, making starting difficult. 3. Fuel quality: After a hot engine shutdown, the engine compartment remains at high temperature. If the fuel is highly volatile, it can form excessive vapor pressure in the fuel rail. When this pressure exceeds the fuel system pressure, vapor lock occurs, causing the injectors to deliver overly lean fuel vapor and resulting in starting difficulties.