Fuel Pressure Regulator
WARNING: This page is about a different car, the 1995 Ford Windstar. However, it is still accessible from the selected car via links, so may be relevant.
Fuel pressure regulator controls fuel pressure supplied to injectors. Regulator is attached to fuel supply manifold assembly, downstream of fuel injectors. Regulator is diaphragm operated. One side of diaphragm senses fuel pressure, and other side is subjected to intake manifold pressure. See Fig 1 .
Fuel pressure is controlled by spring preload applied to diaphragm. Balancing one side of diaphragm with manifold pressure maintains constant fuel pressure at injectors. Excess fuel supplied by pump, but not consumed by engine, passes through regulator and returns to fuel tank through fuel return line.