Fuel Control
Fuel control system handles actual delivery of fuel to engine. See Fig 1 . Fuel from fuel pump enters fuel rail, injectors and pressure regulator. Based upon a manifold vacuum signal, pressure regulator maintains a constant fuel pressure in fuel system of approximately 31-39 psi (2.1-2.7 kg/cm2 ) by allowing excess fuel to return to fuel tank.
Fuel injectors are electrically operated solenoid valves which are energized by the ECU. The ECU determines injector pulse width ("on" time) based upon input from the various sensors.