560SEL (126.039) V8-5.6L (117.968) (1986)
Fuel Pressure Regulator: Description and Operation
Fig. 13 Fuel Pressure Regulator
The primary pressure regulator, Fig. 13, is a variable resistance in the fuel return line from the fuel distributor. The function of the regulator is to
maintain a control pressure that is a constant 0.4 bar (5 psi) below the system pressure.