Fuel Pump Control System

Fuel Pump Control Inputs And Outputs:

PURPOSE
The ECM directly controls the Fuel Pump to reduce power consumption and noise by the pump.

OPERATION
The ECM will cycle a 20 Hz signal to the Fuel Pump turning the ground circuit ON/OFF. If the duty cycle of the signal reaches 100%, then full 12 VDC is reaching the pump and full pump output is achieved.

The ECM will regulate Fuel Pump output based on engine sensor inputs. The Fuel Pump will receive a full 12 VDC when:

The engine is cold
The ignition switch is turned "ON"
The engine is cranking
The engine is hot

All other conditions the ECM will regulate the Fuel Pump voltage.

NOTE: During fuel pump control, the Fuel Pump Relay is bypassed. The only time the relay is used is if the ECM senses a failure in the fuel pump circuit. The relay is then activated and a full 12 VDC is supplied to the pump at all times.