Fuel Pressure: Testing and Inspection

FUEL PUMP FLOW TEST

1. On diesel engine models, connect a suitable hose from diesel fuel filter feed line into a suitable container.
2. On gasoline fuel injection models, relieve fuel pump pressure, then disconnect fuel feed line and install a suitable hose on line. Place other end of hose into suitable container
3. On diesel engines, turn ignition switch to the Run position.
4. On gasoline engines, apply battery voltage to fuel pump test terminal.
5. On all models, fuel pump should supply 1/2 pint or more within 15 seconds.
6. If flow is below minimum, check for fuel restriction. If no restrictions are noted, check pump pressure.




PRESSURE TEST

Gasoline Engine Models
For fuel pump pressure tests, refer to Fuel Injection section under appropriate Fuel Injection System for procedure.




FUEL PUMP OUTLET PRESSURE TEST

Diesel Engines

1. Disconnect fuel line at filter inlet fitting.
2. Connect a rubber hose approximately 8-10 inches long over line, then a suitable pressure gauge. Position gauge so its approximately 16 inches above fuel pump.
3. Turn ignition to Run position and note reading on gauge.
4. Pump operating pressure should be 5.8-8.7 psi. If pressure is too high or too low, replace pump.