Simplified operation: When activated by the Diesel ECM, the Electromagnetic solenoid on top of the injector allows the internal high-pressure hydraulics to lift the needle off its seat and injection takes place. As soon as the solenoid is de-activated, the internal hydraulic pressure forces the needle on its seat and injection is terminated. Multiple injections may occur in one cylinder firing cycle to control the explosive combustion for emission and noise reduction.
The fuel rail and internal injector hydraulic fuel pressure varies dramatically depending on driving and operating conditions which requires the ECM to alter injector opening times (please be aware of safety requirements due to high fuel pressures).
High operating Voltages and current are required to initially start injection. Typically, “Opening Voltage” from 60 - 100V.
A diesel return flow port is located on the injector which can assist in diagnosis. See PlusQuip EQP-107 details here including a short film on testing diesel return flow.
Typical resistance readings for the electrical solenoid circuit is approx. 1 Ohm or less. (useful for identification)
Post fitting procedures are required for correct CRD operation;
Each injector QR code is required to be entered into the ECM.
Pilot Injection leaning procedures also on some systems.