FUEL SYSTEM CONTINUED
Clean, air-free, pressure regulated fuel is supplied to the fuel manifold by the low pressure fuel supply system. Fuel
injectors pressurize the fuel and inject it into the cylinders. Low pressure fuel from the fuel manifold enters the fuel
injector, which uses mechanical force from lobes on the camshaft to pressurize the fuel. Fuel pressures in the fuel
injectors will reach in excess of 30,000 psi (200,000 kPa).
The engine ECM controls the amount of fuel that is injected by varying the signal to each of the fuel injectors. The
fuel injectors will inject fuel only while the fuel injector solenoid is energized. The engine ECM sends a 105V signal
to the fuel injector solenoid in order to energize the fuel injector solenoid. By controlling the timing of the 105V sig-
nal, the engine ECM controls injection timing. By controlling the duration of the 105V signal, the engine ECM con-
trols the amount of fuel that is injected.
Figure 2. Fuel Injector.
Air Cleaner Assembly
Intake air is drawn through a pre-cleaner assembly which prevents large particles of dirt and debris from entering
the air cleaner assembly. Inlet air then flows through the air cleaner assembly which prevents fine particles of dirt
and debris from entering into the turbocharger inlet.
The turbocharger mounts on the exhaust manifold outlet. The turbocharger uses energy from exhaust gas to
compress inlet air to a higher pressure. Compressing inlet air forces more air into the cylinders. Increased airflow
into the cylinders allows fuel to burn with greater efficiency producing more power. A wastegate controls the speed
and pressure of the turbocharger to provide optimum efficiency. The wastegate is adjusted at the factory and is not
Compressed inlet air exiting the turbocharger is very hot. Compressed inlet air exiting the turbocharger is routed
through an after cooler which lowers the temperature of the compressed inlet air. The after cooler mounts on the
side of the engine radiator at the front of the machine. The after cooler is an air-to-air cooler. Cooling occurs as
heat transfers from the compressed inlet air to air flowing past the cooling fins of the after cooler. A fan behind the
radiator pulls air through the after cooler core to cool the compressed inlet air.