Fuel Control (Gasoline Engines): Notes

Precise fuel metering is accomplished with EEC-IV system. The ECA continually monitors engine operating conditions based on information received from various sensors and switches. In response to information received, ECA calculates optimum air/fuel mixture in relation to present engine operating conditions and affects required metering adjustments through output actuators control.

In the future, remember that discussion about fuel pumps, such as the following paragraph, belongs in the Fuel Delivery section. When ignition switch is turned to START position, ECA operates fuel pump relay to provide fuel for starting engine. 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. 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.