3500 4x4 Pickup L6-359 5.9L DSL Turbo (1996)
Fuel Injector: Description and Operation
Fuel Injector Operation
DESCRIPTION
The injectors consist of the nozzle holder, 0-ring water seal, shims, spring, needle valve and nozzle. Fuel enters the injector at the fuel inlet (top of
injector) and is routed to the needle valve bore. When fuel pressure rises to approximately 25,500 kPa (3,700 PSI) to 26,900 kPa (3,900 PSI), the
needle valve spring tension is overcome. The needle valve rises and fuel flows through the spray holes in the nozzle tip into the combustion
chamber. The pressure required to lift the needle valve is the operating pressure setting. This is sometimes referred to as the POP pressure setting.
Fuel pressure in the injector circuit decreases after injection. The injector needle valve is immediately closed by the needle valve spring and fuel
flow into the combustion chamber is stopped. Exhaust gases are prevented from entering the injector nozzle by the needle valve.
