The engine starts normally when it is cold, but it is difficult to start when it is hot. The most common reason is that the mixture is too rich, but the mixture is too thin for some reason.
1. The injector drips. The more serious the injector drips, the richer the mixture will be. Do the fuel injection test of the fuel injector, and the leakage of each fuel injector shall not exceed 1 drop in 30s. The trouble can be eliminated by replacing the dripping injector.
2. The air filter in the carbon canister is blocked, which makes the only channel between the fuel tank and the atmosphere closed. With the decrease of the oil level in the tank, the vacuum degree in the tank increases gradually. The bottom of the fuel tank deforms under the dual effects of the external atmospheric pressure and the vacuum suction of the internal fuel pump, and the bottom of the fuel tank starts to close to the fuel pump filter. When the hot car is restarted after flameout, the inlet of the fuel pump filter is blocked, which leads to the lean mixture after the hot car and the difficulty of starting. After a long time of parking, without the vacuum suction of the fuel pump, the bottom of the fuel tank will return to the original position due to elasticity, so it can start normally. Open the fuel tank cap before restarting after the hot car is stopped. If the car can be started normally, it means that the air filter in the canister is blocked. If the canister is replaced, the fault can be eliminated.
3. The cold start is normal, and the hot start is normal immediately after the flameout, but it is difficult to start after 20 minutes after the flameout, and there will be idle jitter after starting. This shows that the fuel holding pressure is too low, and the high temperature of the engine after the hot car leads to the evaporation of fuel in the fuel pipe, resulting in gas resistance. The fuel pressure should be further detected to find the good place of the internal street seal of the fuel system.