- 1). Locate the fuel system test port on the fuel system rail. The rail resembles a tube running between the fuel pump and the throttle body (or carburetor) and has what looks like a tire air valve stem with cap. Be certain you do not mistake the AC access tube for the fuel system rail. If in doubt, trace the line in both directions to be sure it is not connected to the air conditioning compressor.
- 2). Unscrew the cap from the fuel system test port with your fingers. If the cap sticks twist it gently with the pliers.
- 3). Screw the hose fitting of the fuel pressure gauge onto the test port. Set the gauge where it will not be vulnerable to moving parts of the engine, and start the vehicle.
- 4). Read the fuel pressure gauge, and then remove the rubber vacuum line attached to the throttle body (or carburetor) assembly. If the reading on the gauge does not increase at least 5 psi after the vacuum line is removed, the fuel pressure regulator is faulty.