Fuel Pump Control

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

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