Injector failure Injector failure is generally manifest […]
Injector failure Injector failure is generally manifested as: the injector nozzle is blocked by colloidal objects, and the carbon deposit or sealing is not strict, resulting in dripping, resulting in too little or too much concentration of the mixture. The detection method is: first start the engine, check the operation sound at each injector with a stethoscope, if the sound is not heard, check the wiring connector, the injector or the injection signal from the ECU; then, measure with a multimeter If the resistance between the injector terminals does not match the specified value, replace the injector. Finally, check the fuel injection amount of the injector. The value should be within the normal range and the difference between the injection quantities of each cylinder is less than 5cm3.
water temperature sensor failure Water temperature sensor is used to detect the temperature of the cooling water, and convert it into a temperature-related voltage signal input to the ECU, as the basis for the ECU to correct the fuel injection. If the water temperature sensor fails or the wiring between the ECU and the ECU is broken, short-circuited, or the surface scale is severe, the output signal will be greatly deviated, and eventually the injector will not increase or decrease the fuel injection amount in time, resulting in difficulty in starting.
Idle speed control valve (ISC) failure Most EFI engines use stepping motor type idle speed control valve. The ECU adjusts the energization sequence of the stepper motor electromagnetic coil according to the working condition of the engine, so that the stepper motor shaft cone The valve body is screwed in or out, and the opening degree of the bypass air passage is adjusted to realize the adjustment of the bypass intake air amount. If the engine is difficult to start but can be started by stepping on the throttle, the idle control valve is faulty. Disassembling the ISC valve will result in more carbon deposits, colloidal viscosity, and oil accumulation on the tapered surface of the valve body. As a result, the adjustable range of the conical valve is reduced, resulting in a decrease in the intake air amount and the mixture when the cold car is started. Excessive concentration and difficulty in starting up.