1974-76 Models

Disconnect return line from fuel tank and place hose in container to trap discharged fuel. Start engine and check that fuel is discharged from fuel return line. If fuel is not discharged, check return line for damage. If return line is okay, reconnect line and go to next step.
Disconnect pressure line between fuel pump and main fuel filter. Install Tester (000 589 49 21 00) on pressure line. Bleed tester and fuel system. See BLEEDING FUEL SYSTEM in this article. Check pressure at tester with engine running at idle speed. Pressure should be 14.7-22.0 psi (1.0-1.5 kg/cm² ).
Raise engine speed to 3000 RPM. Pressure should read 32 (2.2 kg/cm² ). If pressure is much higher or lower, check that by-pass valve is opening properly. Next, check final delivery pressure. Using fingers, squeeze hose between tester and main fuel filter. If pump is working properly, pressure should be at least 29 psi (2.0 kg/cm² ).