Fuel Pump: Description and Operation

SYSTEM DESCRIPTION
Fuel pump ON-OFF control
The ECM activates the fuel pump for several seconds after the ignition switch is turned ON to improve engine start-up. If the ECM receives a 120 signal from the camshaft position sensor, it knows that the engine is rotating, and causes the pump to activate. If the 120 signal is not received when the ignition switch is ON, the engine stalls. The ECM stops pump operation and prevents the battery from discharging, thereby improving safety. The ECM does not directly drive the fuel pump. It controls the ON/OFF fuel pump relay, which in turn controls the fuel pump.




OPERATION
Refer to the accompanying image for fuel pump operation.