Pressure Regulator

The pressure regulator is located downstream from the fuel injector, on the throttle body. The regulator is equipped with a spring loaded rubber diaphragm which covers a fuel return port. Fuel flow past the injector enters the regulator, and is restricted from flowing back to the tank by the blocked return port.

When fuel pressure reaches 36 psi (2.5 kg/cm² ), the spring is compressed enough to allow fuel into the return line. The diaphragm and spring assembly are constantly opening and closing to maintain fuel pressure at this constant value.

In addition to the spring rate, further control of fuel pressure is provided by a vacuum line from the regulator to a vacuum port located in the throttle body, above the throttle plate.

As venturi vacuum increases, less pressure is required to introduce the same amount of fuel into the air stream. This vacuum assist allows for additional fine tuning of fuel pressure under all engine operating conditions.