Fuel Delivery and Air Induction: Description and Operation

The fuel delivery system is comprised of an in-tank electric fuel pump, an in-line fuel filter, a fuel pressure regulator and a fuel injector.
The in-tank electric fuel pump is attached to the fuel gauge sending unit and is controlled by the ECU. It delivers and maintains fuel pressure at a standard operating pressure of 14.5 psi. The replaceable in-line fuel filter is located under the right rear floor pan. The fuel pressure regulator is an integral part of the throttle body and consists of a spring chamber that is vented to the same pressure as the tip of the injector. Since differential pressure between the injector nozzle and the spring chamber is the same, the volume of fuel delivered is only dependent on the length of time the injector solenoid is energized. Since the fuel pump delivers fuel in excess of engine requirements, the pressure regulator sends some fuel back to the fuel tank via the fuel return hose. The pressure regulator acts independently of the ECU. The fuel injector is controlled by the ECU and directs and meters fuel into the throttle bore. The fuel injector body consists of a solenoid plunger that is pulled upward by the solenoid armature. This permits the spring loaded ball valve to move from its seat, allowing fuel to pass through the injector nozzle.