1. Start the engine and let it idle.
2. Use a stethoscope and, without turning off the engine, listen to how each injector works.
When operating, the injector makes a clicking sound caused by the opening and closing of the injector.
If you don't have a stethoscope, you can use a screwdriver or simply put your finger on the nozzle and feel to make sure that the nozzle is working.
If the noise of the working injectors is not heard, then you should check the voltage supply to the injectors, as well as its resistance and tightness.
Checking the power supply 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 LED lamp to both contacts of the plug. Ask an assistant to work the starter.
The LED light should blink. If the LED light does not blink, the power supply wire may be broken or the cause of the injector failure may be a defective control unit.
Text republished from the website: mercedesman
4. Turn off the ignition.
5. Connect an ohmmeter to both contacts of each injector and measure the resistance of the injectors one by one. If the resistance on one of the injectors does not correspond to the nominal values, then this injector should be replaced.