Fuel Pressure Regulator: Service and Repair

The function and appearance of the line pressure are the same as before. However, the shims are now annular. The shut-off valve for return fuel from the control pressure circuit is located in the screw plug.
After replacement of the O-ring, the line pressure must be checked and adjusted. Pressure is increased by installing additional shims and decreased by removing shims. Shims are available in thicknesses of .004 inches and .020 inches. A .004 inch shim produces a 0.15 bar change in pressure. A prerequisite for measuring and adjusting the line pressure is that the fuel pump capacity is correct. The screw plug should be torqued to 9.4-10.8 ft. lbs. (13-15 Nm).