Caravan AWD V6-201 3.3L (1991)
Fuel Pressure Regulator: Description and Operation
Fuel Pressure Regulator
The fuel pressure regulator is used to maintain a constant pressure differential at the fuel injector tip of 48 psi. The pressure regulator uses a vacuum
assisted spring loaded diaphragm to control the fuel return port in order to maintain constant pressure. Pressurized fuel is delivered first to the fuel
injector and then flows to the pressure regulator. When fuel pressure acting on the regulator diaphragm exceeds 48 psi, the regulator spring is
compressed and the fuel return port is opened. When fuel pressure drops below 48 psi, spring tension causes the diaphragm to block the fuel return port.
As manifold vacuum increases during deceleration, less pressure is needed to supply the same amount of fuel into the air flow. In order to fine tune the
fuel pressure under all operating conditions, the vacuum assists in opening the fuel port during high vacuum conditions.
