TL960 SERVICE MANUAL
blocking high pressure oil from entering the injector. The plunger and intensifier are at the top of their bore and the plunger cavity is full of fuel. Fuel pressure in the plunger cavity is the same as fuel rail pressure, about 30 psi, depending on conditions.
Injection: When the ECM determines the injector should fire, the following sequence of events occurs:
ECM sends signal pulse to injector solenoid, Solenoid is fully energized almost instantly creating a strong magnetic pull on the armature.
The armature is connected to the poppet valve. The injection process begins when: Magnetic pull of solenoid overcome spring tension holding the poppet closed, Poppet is quickly raised off its seat.
When poppet valve opens: Upper poppet land closes off path to drain, Lower land opens poppet chamber to incoming high pressure oil,