Injector leakage faults are generally classified into internal leakage and external leakage. The reason for the internal leakage of the injector is that it wears out early in use, causing it to leak fuel into the intake manifold under the pressure of the system. The external leakage of the injector occurs mostly at the connection between the injector and the fuel rail, and the sealing surface is sealed. If the gasoline leaks outside the intake manifold, the oil will drip on the cylinder block and will evaporate in the engine compartment when it is heated. Once an electric spark occurs, it will cause a fire at any time, and the consequences are very serious. When the injector leaks internally, it will cause the fuel injected by the injector to be atomized, resulting in unstable engine operation, incomplete combustion of the mixture, black smoke from the exhaust pipe, and fuel for the vehicle. The consumption has increased significantly. When an external leakage fault occurs in the injector, it may cause difficulty in starting the engine, idling, power loss, fuel consumption increase, running surge and poor acceleration. In addition, when the sealing surface at the junction of the injector and the intake pipe is damaged, the intake system may leak, causing additional air to enter the engine combustion chamber, causing the mixture to be lean, causing abnormal engine operation.