Fuel Delivery
A high pressure electric fuel pump, located inside fuel tank, supplies fuel to the injectors. The pump receives power through a vacuum controlled by-pass relay, a fuel pump relay, and an inertia switch. The vacuum controlled relay is activated by a vacuum switch connected to manifold vacuum. This supplies power to the fuel pump relay only when engine is running and vacuum is present in manifold.
The fuel pump relay is activated by the ECA with the ignition switch in the "ON" or "START" mode. When the ignition switch is turned to the "ON" position, both relays are activated for approximately 1 second to supply initial line pressure to the system. If the engine stalls or is not started within 1 second the ECA will shut off power to fuel pump.
The inertia switch, located in the trunk, is designed to open the fuel pump power circuit in the event of a collision. This switch is reset by pushing both buttons, on switch, simultaneously. The inertia switch should not be reset until fuel system has been inspected for damage or leaks.
Fuel is pumped through fuel filters to the fuel injectors and pressure regulator mounted on throttle body. The fuel pressure regulator controls fuel pressure to 39 psi across the fuel injectors. Fuel in excess of that used to maintain constant pressure is returned to fuel tank through the fuel return line.
Injectors are actuated, spraying calculated amount of fuel into engine, at twice the crankshaft speed. Only open time varies to satisfy fuel requirements.