Fuel Pump Control Unit
Fuel pump control unit is located above fuel tank at rear of vehicle. Based upon signals from the ECU, control unit regulates voltage supplied to fuel pump. By increasing or decreasing current flow through fuel pump, fuel volume can be adjusted to one of 3 levels.
During engine cranking, engine operation when coolant temperature is less than 32°F (0°C), engine load and high speed operation, high voltage (11-14 volts) is applied to fuel pump. This produces maximum volume. During middle load and middle speed conditions, medium voltage (7.8 volts) is applied to fuel pump. This produces medium fuel volume. During all other modes of operation low voltage (5.6 volts) is applied to fuel pump, providing minimum volume.
Fuel pump control unit is operated by ECU.