Throttle Body Assembly
The throttle assembly contains the following components
- The throttle blade
- The throttle actuator motor
- The throttle position (TP) sensor 1 and 2
The throttle body functions similar to a conventional throttle body with the following exceptions
- An electric motor opens and closes the throttle valve.
- The throttle blade is spring loaded in both directions and the default position is slightly open.
- There are 2 individual TP sensors within the throttle body assembly.
The TP sensors are used to determine the throttle plate angle. The TP sensors provide the engine control module (ECM) with a signal voltage proportional to throttle plate movement. The TP sensor 1 signal voltage at closed throttle is above 4 volts and decreases as the throttle plate is opened. The TP sensor 2 signal voltage at closed throttle is below 1 volt and increases as the throttle plate is opened.
Fuel Pressure Regulator Assembly
The fuel pressure regulator is a diaphragm-operated relief valve located in the modular fuel pump and sender assembly. Its principal function is to maintain a controlled pressure at the injectors at all times by regulating fuel flow into the fuel feed line. The injector pulse width varies with the signal from the manifold absolute pressure (MAP) sensor. With the ignition ON and the engine OFF, system fuel pressure at the pressure test connection should be 380-440 kPa (55-64 psi). If the pressure is too low, poor performance could result. If the pressure is too high, excessive odor and a Diagnostic Trouble Code (DTC) may result. Refer to LINK 31918 for information on diagnosing fuel pressure conditions.
Fuel Filter Assembly
The fuel filter assembly is contained within the modular fuel pump and sender assembly reservoir and forms the containment housing for the fuel pump. The filter comprises a paper element which traps particles in the fuel that may damage the fuel injection system. The fuel filter is made to withstand maximum fuel system pressure, changes in temperature and exposure to fuel additives.
Fuel Level Sender Assembly
The fuel level sender assembly comprises of a fuel level float and wire arm assembly, a ceramic variable resistor card assembly, and a detachable nylon wiper. The ceramic resistor card is attached to a plastic card holder which attaches to the reservoir. A metal contact fork with brushes is connected to the detachable nylon wiper. This assembly provides a variable circuit resistance to the engine control module (ECM) depending on wiper contact position. Two circuit wires run from the resistor card and extend up to connect with the modular fuel pump to cover assembly wiring connector on the underside of the modular fuel pump and sender assembly cover. The ECM averages out any slosh variation in the fuel tank and sends this signal to the fuel level indicator on the instrument panel fuel gauge.