• Intake manifold vacuum is introduced to the diaphragm chamber of the pressure regulator. When the differential pressure exceeds approx. 280 kPa {2.9 kgf/cm
2, 41 psi}, the valve opens to return the fuel to the fuel tank. Because of this, the fuel pressure (relative pressure) to the intake manifold vacuum is always maintained at approx. 280 kPa {2.9 kgf/cm
2, 41 psi} while the engine is running.
