Fuel Pump Module
All models are equipped with an in-tank fuel pump module which includes a fuel strainer, gauge float, gauge sending unit, pressure regulator and pump. See Fig 1 .
Turbine-type electric pump is driven by a permanent magnet, 12-volt electric motor. Voltage to operate pump is supplied by PCM through a common ASD relay and fuel pump relay circuit. Fuel is drawn in through a separate filter/strainer at bottom of fuel pump and pushed through pressure regulator to fuel outlet line (to fuel injectors).
Fuel pressure regulator is a mechanical device calibrated to maintain fuel system operating pressure at 47-51 psi (3.4-3.7 kg/cm2 ) across injector tips. If fuel pressure is more than specified, an internal rubber diaphragm and calibrated springs will move from open to closed position, returning excess fuel directly into fuel tank through regulator without using a return line. When fuel pump is not operating, some fuel pressure is maintained by a fuel pump outlet check valve to help with engine start-up.