Fuel Pump: Description and Operation

Fuel Tank And Components:

Purpose
The fuel pump supplies fuel under pressure to the injection manifold assembly.

Location
The fuel pump is located in the fuel tank.

Construction
The fuel pump is a submersed circumference flow pump comprised of a DC motor, impeller, pump casing, and pump cover. The assembly utilizes an inlet filter, a pressure relief valve, and a check valve.

High Pressure Elecric Fuel Pump:

Operation
When the engine is started (ignition switch is in ST position), the coil L2 is energized to turn on the switch. Then, the fuel pump starts driving. When the engine is running (ignition switch is in IG position), the crankshaft position sensor signal is input to ECM, and ECM energizes the multi port fuel injection relay coil L1 to keep the switch "ON". Therefore, the fuel pump continues driving.
If the crankshaft position sensor signal is not detected by the ECM for 0.6 seconds or more because of engine stop, etc., the ECM immediately turns OFF switch S1 to stop the fuel pump. This assures safety when an abnormality occurs.