Aerostar AWD V6-245 4.0L (1990)
Fuel Pressure Regulator: Description and Operation
Fuel Pressure Regulator
The pressure regulator and fuel pump work together to maintain the required constant pressure at the injector tips. The regulator consists of a
spring-loaded diaphragm-operated valve in a metal housing.
The pressure regulator is located on the fuel supply manifold and installed on the return (downstream) side of the injectors. Downstream regulation
minimizes fuel pressure pulsations caused by pressure drop across the injectors as the nozzles open. This design ensures positive fuel pressure at the
injectors at all times and holds residual pressure in the lines when the engine is off.
The pressure regulator used in a multipoint injection system has an intake manifold connection on the regulator vacuum chamber. This allows fuel
pressure to be modulated by a combination of spring pressure and manifold vacuum acting on the diaphragm.
Fuel in excess of that used by the engine, is bypassed through the regulator and returns to the fuel tank. The regulator shuts off the return line when the
fuel pump is not running. This maintains pressure at the injectors for easy restarting and reduced vapor lock.
