The pressure regulator is a mechanical device located downstream of the fuel injector on the throttle body. Its function is to maintain a constant 14.5 psi (100 kPa) across the fuel injector tip. The regulator uses a spring loaded rubber diaphragm to uncover a fuel return port. When the fuel pump becomes operational, fuel flows past the injector into the regulator, and is restricted from flowing any further by the blocked return port. When fuel pressure reaches the predetermined setting, it pushes on the diaphragm, compressing the spring, and uncovers the fuel return port. The diaphragm and spring will constantly move from an open to closed position to keep the fuel pressure constant.
REMOVAL & INSTALLATION
See Figure 1
- Remove the air cleaner assembly.
- Perform the fuel system pressure release.
- Disconnect the negative battery cable.
- Remove the screws (usually 3) attaching the pressure regulator to the throttle body. Place a shop towel around the inlet chamber to contain any fuel remaining in the system.
- Pull the pressure regulator from the throttle body.
- Carefully remove the O-ring from the pressure regulator and remove the gasket.
- Place a new gasket on the pressure regulator and carefully install a new O-ring.
- Position the pressure regulator on the throttle body press it into place.
- Install the screws and torque them to 40 inch lbs. (4.4 Nm).
- Connect the negative battery cable.
- Test for leaks using ATM tester C-4805 or equivalent. With the ignition in the RUN position depress ATM button. This will activate the pump and pressurize the system. Check for leaks.
- Reinstall the air cleaner assembly.