Fuel Charging and Controls
Fuel Charging and ControlsComponent Location:
Component Location
The fuel charging and controls system consists of:
^ fuel pressure regulator
^ fuel injection supply manifold
^ fuel injector
^ fuel shut off valve solenoid
^ fuel pressure relief valve
^ injection pressure sensor
^ engine fuel temperature sensor
^ fuel charging wiring harness.
Fuel Pressure Regulator
The fuel pressure regulator is located on the inside of the LH frame rail just forward of the transmission support crossmember. It is part of an assembly that includes the coalescer/filter. The fuel pressure regulator reduces the line pressure from tank pressure, 20,685 kpa (3000 psi) to line pressure, 655 kpa (95 psi).
Fuel pressure regulator heating is provided by two 3/8-inch taps from the existing heater supply and return hoses on the back of the engine. Two high-temperature 3/8-inch ID heater hoses (packaged with the front low pressure fuel line) are used to connect the fuel pressure regulator to the tap points on the engine heater hoses.
Refer to low pressure fuel procedure for fuel pressure regulator heater hose replacement. Low Pressure Lines
Fuel Injection Supply Manifold
Fuel Injection Supply Manifold:
The fuel injection supply manifold delivers line-pressure fuel from the vehicle fuel supply line to the fuel injectors. The fuel injection supply manifold consists of the following:
^ a tubular fuel rail
^ eight fuel injector connectors
^ a fuel pressure relief valve
^ a fuel shut off valve solenoid
^ mounting attachments that locate the fuel injection supply manifold and provide fuel injector retention
^ a fuel inlet connection that has a push-connect fitting
^ an injection pressure sensor
^ an engine fuel temperature sensor
Fuel Injectors
The natural gas fuel injectors are electromechanical devices that meter fuel delivered to the engine. The natural gas fuel injectors are mounted in the lower intake manifold and are positioned so that their tips direct fuel just ahead of the engine intake valves. The natural gas fuel injector bodies consist of a solenoid and a needle and valve assembly. Natural gas fuel injectors can be identified by an aqua cap on the injector body.
Fuel Shutoff Valve Solenoid
The fuel shut off valve solenoid seals the upstream fuel pressure from entering the fuel injection supply manifold when the engine is not running. The fuel shut off valve solenoid is open only when it is activated by the solenoid valve (fuel pump) relay.
Fuel Pressure Relief Valve
The fuel pressure relief valve is located on the fuel injection supply manifold, and is used to relieve fuel system pressure from the fuel delivery system.
Injection Pressure Sensor
The injection pressure sensor is located on the fuel injection supply manifold, and is used to provide a signal to the powertrain control module (PCM) that is proportional to pressure in the fuel injection supply manifold.
Engine Fuel Temperature Sensor
The engine fuel temperature sensor is located on the fuel injection supply manifold, and is used to provide a signal to the powertrain control module that indicates the temperature of the fuel in the fuel injection supply manifold.
Fuel Charging Wiring
Fuel Charging Wiring:
The fuel charging wiring is a single harness that includes electrical connectors for the fuel injectors, ignition coils and various sensors, valves and senders, which monitor all engine functions.