K 2500 Suburban 4WD V8-454 7.4L (1994)
Fuel Pressure Regulator: Description and Operation
IAC Valve Operation And Fuel Pressure Regulation
Purpose
The purpose of the regulator is to maintain a constant pressure to the injectors at all times
Operation
Fuel pressure is regulated by the difference between fuel pump pressure acting on one side of the diaphragm and the force of the calibrated spring
(and air cleaner air pressure) acting on the other side. The system operates in an acceptable pressure range of 62 to 90 kPa (9 to 13 psi) on 4.3L, 5.0L
and 5.7L engines. The pressure range is 179 to 220 kPa (26 to 32 psi) on 7.4L engines.
If fuel pressure is too low, poor performance could result. If the pressure is too high, excess emissions and unpleasant exhaust odor may result.
Construction
The pressure regulator is part of the fuel meter, and contains an air chamber and a fuel chamber that are separated by a diaphragm-operated relief
valve and a calibrated spring.
NOTE: The pressure regulator on this unit is serviced as part of the fuel meter cover and should not be disassembled.
