Fuel Control
An electric in-tank fuel pump supplies fuel to the throttle body. Fuel enters the fuel bowl reservoir of the throttle body, through the injector and fuel pressure regulator. The fuel pump is controlled by the ECU. The fuel injector and fuel pressure regulator are integral components of the throttle body.
The fuel pressure regulator is a diaphragm operated relief valve which maintains fuel pressure of 14.5 psi (1 kg/cm2 ). Fuel in excess of this pressure is returned to fuel tank by a fuel return line.
Since fuel pressure at the injector is kept constant, the volume of fuel injected is dependent only on the length of time that the injector is energized. The ECU controls the pulse width (on/off time) of the injector based upon engine operating requirements. During engine start-up, the injector delivers an extra amount of fuel to aid in starting.