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