Pic. 2.251. Checking injectors with a stethoscope
Use a stethoscope to listen to the clicks of the injectors at idle (pic. 2.251).
Verify that the click rate increases with engine speed.
Note. Listen in such a way that clicks are not transmitted through the fuel rail to the idle injector from the adjacent injector.
Pic. 2.252. Checking the operation of the nozzle with a finger
If you don't have a stethoscope, test the injectors by placing your finger on them (pic. 2.252).
If no vibration is felt, check the electrical connector, injector, or control signal from the engine control unit.