Injectors and Poppet Nozzles

Injector And Poppet Nozzle Assembly:

Each fuel injector assembly is a solenoid-operated device, controlled by the VCM. The fuel injector assembly meters the pressurized fuel through a poppet nozzle (5) to a single engine cylinder.

The VCM energizes the injector solenoid, which opens an armature valve (3), allowing fuel to flow past the ball valve and through a fuel tube (1) to the poppet nozzle.

An increase in fuel pressure causes the poppet nozzle ball to open from its seat against the extension spring force. This allows the fuel to flow from the nozzle (at approximately 280 kPa (40 psi)).

De-energizing the injector solenoid (4) closes the armature. De-energizing also reduces the fuel pressure acting on the poppet nozzle ball. The extension spring closes the ball to the seat. The extension spring also checks the pressure between the ball and seat and the injector armature and fuel tube shutoff. The flow control solenoid assembly (2) is electrically activated to allow fuel to flow from the injector to the flexible fuel line to the poppet nozzle.

An injector poppet nozzle that is stuck partly open would cause a loss of pressure after the engine shut down. Consequently, the driver would notice long cranking times on some engines. Dieseling could also occur because the fuel injector could deliver some fuel to the engine after the driver turns the ignition to OFF. These components are diagnosed in The Injector Balance Test and The Injector Coil Test. Refer to Fuel Injector Balance Test with Tech 2. Refer to Fuel Injector Coil Test.