Fuel Pump Control Unit

Fuel pump control unit is located above fuel tank at rear of vehicle. Based on signals from ECM, 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 (high, medium and low).

High voltage (battery voltage) is applied to fuel pump during the following conditions: engine cranking, engine operation when coolant temperature is less than 32°F (0°C), and high-speed operation or heavy engine load. 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 ECM.