Fuel Boost Pump / Fuel Transfer Pump

Figure 3-3: Fuel Lift Pump Electrical Circuit:

The electrical circuit for the lift pump involves several main components (Figure 3-3). A relay mounted in the exterior fuse box, and the lift pump itself, mounted near the filter on the left side of the engine compartment.

When the driver moves the ignition switch to the "RUN" position, the lift pump relay is energized by the PCM for 5 to 20 sec., depending on PCM time out.

As soon as the PCM receives RPM signals from the EFI pump the relay is energized again. The lift pump remains running as long as the engine runs.