SL L4-1.9L DOHC VIN 7 (1992)
Fuel Pressure Regulator: Description and Operation
Fuel Pressure Regulator Diagram.
Disconnection Of Fuel Line Fitting At Regulator.
DESCRIPTION
The pressure regulator assembly is a diaphragm operated relief valve with fuel pump pressure on one side, and regulator spring pressure and intake
manifold vacuum on the other. The regulator maintains a constant pressure differential across the injectors at all times by the amount of pressure it
takes to lift the diaphragm off its seat. During idle, a high vacuum signal to the pressure regulator pulls on the diaphragm, helping to lift it off its
seat. This allows for a low fuel pressure during idle. As engine load increases, vacuum drops, allowing the fuel pressure to increase. When vacuum
drops to zero, spring pressure controls fuel pressure. This spring is preset at the factory and no adjustment is required. By varying fuel pressure
according to engine vacuum a constant pressure differential across the injector openings in maintained.
DIAGNOSIS
With the ignition in the "ON" position and engine OFF (zero vacuum), fuel pressure at the pressure test connection should be 262-306 kPa (38-44
psi). If the pressure is to lower than specification, poor performance and a Code 44 could result. If the pressure is too higher than specification,
excessive odor and a Code 45 could result.
LOCATION
The pressure regulator is mounted at the end of the fuel rail, and is serviced as a complete assembly.
