Engine Driven Fuel Pump - Field Test Procedure
Number 84-6 (Gasoline)-14 Date 12/83Subject: FIELD TEST PROCEDURE ENGINE DRIVEN FUEL PUMP - ALL VEHICLES EQUIPPED WITH ENGINE DRIVEN LARGE DIAMETER FUEL PUMPS
Models with fuel return lines;
1. Engine at normal operating temperatures.
2. Disconnect fuel hose from fuel tank to pump at the pump.
3. Connect known good vacuum gage to fuel pump suction pipe.
4. Crank engine for 10 seconds, vacuum gage should read 15" vacuum and hold there for at least 15 seconds.
If pump does not pass this test, replace pump.
Models without fuel return lines;
1. Engine at operating temperatures.
2. Disconnect fuel hose from fuel tank to pump at the pump.
3. Connect known good vacuum gage to fuel pump suction pipe.
4. Crank engine for 10 seconds, vacuum gage should read 12" vacuum but due to design will not hold this reading.
If this 12" reading is not obtained during cranking for 10 seconds replace pump.