1. Start the engine and let it idle.
2. Use a stethoscope and, without turning off the engine, listen to how each nozzle works.
During operation, the nozzle makes a clicking sound caused by the opening and closing of the nozzle.
If there is no stethoscope, then you can use a screwdriver or just put your finger on the nozzle and feel that the nozzle is working.
If the noise of the operating injectors is not audible, then you should check the voltage supply to the injectors, as well as its resistance and tightness.
Checking the power and resistance of the injector
3. Check the voltage supply to the injector. To do this, disconnect the plugs from the injectors and connect a control diode bulb to both pins of the plug. Have an assistant run the starter.
The LED light should flash. If the diode lamp does not blink, then the power wire may be broken, or the cause of the injector failure may be a defect in the control unit.
4. Turn off the ignition.
5. Connect an ohmmeter to both pins of each injector and measure the injector resistance one by one. If on one of the injectors the resistance does not correspond to the nominal values, then this injector should be replaced.