Fuel Pressure Regulator

Fuel pressure regulator is a spring/vacuum operated diaphragm-type relief valve which maintains a constant regulated fuel pressure under all vehicle operating modes. When manifold vacuum is high (low fuel requirements), diaphragm is drawn in, counteracting spring pressure. In this condition, excess fuel is routed back to fuel tank. When manifold vacuum drops (engine load), spring pressure overcomes vacuum, closing off fuel tank return line. This maintains pressure and volume to injector(s).