Fuel Pump Control Operation

When ignition switch is turned to "ON" position, EEC power relay is energized (contacts closed). Power is provided to fuel pump relay and to timing device in ECA. Fuel pump receives power through fuel pump relay contacts. If ignition switch is not turned to "START" position, timing device in ECA will open ground circuit after approximately one second. ECC senses engine speed and shuts off fuel pump by opening ground circuit to fuel pump relay when engine stops, or when engine drops below 120 RPM.

Opening ground circuit de-energizes fuel pump relay (contacts opened) and de-energizes fuel pump. This function allows pressurization of fuel system. When ignition switch is turned to "START" position, ECA operates fuel pump relay to provide fuel for starting engine while cranking.