Low Pressure Fuel Pump Testing

CAUTION: Fuel system is under pressure. Before removing and fuel lines, depressurize fuel system. Disconnect inertia switch and crank engine for a minimum of 15 seconds to depressurize system.

Check fuel tank(s) for adequate fuel supply. Check for fuel leaks at fittings and lines. Install jumper lead to fuel pump test terminal of VIP test connector. See Figure . Use a test lead long enough to reach under vehicle. Raise vehicle and ground test lead. Use a stethoscope and listen for pump operation. If low pressure pump is running, go to step 2). If not, go to step 3).
Disconnect test lead from ground. Remove reservoir inlet hose at reservoir. Place fuel hose in one quart calibrated container and ground test lead for 5 seconds. Fuel level should be at least 6 ounces. If fuel pump volume is correct, fuel pump is okay. If not, restrict fuel line momentarily to prime pump. If no flow develops, check for blocked fuel lines. If no blockage is found, replace pump.
If pump does not run, inspect all electrical connections. Check inertia switch and fuel pump relay for operation. If high pressure pump runs, but low pressure pump does not and voltage is present, replace low pressure fuel pump.