Engine Controls - 2.2L (L61) - Introduction: Overhaul Saturn ION I

Fuel Sender Assembly

The fuel sender assembly consists of the following major components

1. The fuel level sensor
2. The fuel tank pressure (FTP) sensor
3. The fuel pump module
4. The fuel pressure regulator

Fuel Rail Assembly

The fuel rail assembly attaches to the engine intake manifold. The fuel rail assembly performs the following functions

1. Positions the injectors (5) in the intake manifold
2. Distributes fuel evenly to the injectors
3. Integrates the fuel pulse dampener (2) into the fuel metering system

Scheme 23

Fuel Pressure Regulator Assembly

The fuel pressure regulator attaches to the fuel return pipe on the fuel sender assembly. The fuel pressure regulator is a diaphragm relief valve. The diaphragm has fuel pressure on one side and regulator spring pressure on the other side. Fuel pressure is controlled by a pressure balance across the regulator. The fuel system pressure is constant and is no longer a function of engine load or manifold vacuum. A software bias compensates the injector on-time based on the signal from the MAP sensor.

Scheme 24

The fuel pulse dampener attaches inside a housing on the fuel rail assembly. The fuel pulse dampener is diaphragm-operated, with fuel pump pressure on one side and with spring pressure on the other side. The function of the dampener is to dampen the fuel pump pressure pulsations.

Throttle Body Assembly

The throttle assembly contains the following components

1. The throttle blade
2. The throttle actuator motor
3. The throttle position (TP) sensor 1 and 2

The throttle body functions similar to a conventional throttle body with the following exceptions

1. An electric motor opens and closes the throttle valve.
2. The throttle blade is spring loaded in both directions and the default position is slightly open.
3. 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 ECM with a signal voltage proportional to throttle plate movement. The TP sensor 1 signal voltage at closed throttle is near the 5-volt reference and decreases as the throttle plate is opened. The TP sensor 2 signal voltage at closed throttle is near the low reference and increases as the throttle plate is opened.