Fuel Conditioning Module Pressure Test Recommended Procedure

NOTE: Restrictions in the fuel line may cause continuous aeration.

Make sure the valve on the Diesel Fuel Flow Tester 310-193 or equivalent is closed.
Using the male and female tool plugs included with the Diesel Fuel Flow Tester 310-193 or equivalent, plug the fuel return line between the secondary fuel filter and the fuel conditioning module. Plug the fuel conditioning module fuel return inlet port.
Install the Adapter, Fuel Pressure Test 310-111 or equivalent with the Gauge 0-1,100 kPa (0-160 psi) Bar (part of DSL ENG Pressure Test Kit 014-00761 or equivalent) between the fuel conditioning module outlet port and the fuel supply line leading to the secondary fuel filter.

Fig 1: Locating Fuel Pump Adapter 310-111
Courtesy of FORD MOTOR CO.
Start the engine and let it idle.
Open the valve on the Diesel Fuel Flow Tester 310-193 or equivalent.
Run the engine until fuel flows free from cloudiness, gelling (cold weather) or aeration. If the fuel continues to be cloudy or gelled, refer to the SUFFICIENT CLEAN FUEL test. If the air bubbles can not be purged, check for kinks or leaks in the vehicle fuel system as well as the test tool.
Access and monitor the B+ PID. Verify the battery and charging system are working correctly and the battery voltage is greater than 11.5 volts. Refer to the appropriate Charging System article for diagnosis as necessary.
Record the maximum fuel pressure at the fuel conditioning module outlet while the valve on the Diesel Fuel Flow Tester 310-193 or equivalent is open and fuel is flowing back to the fuel tank.

If the fuel pressure at the fuel conditioning module outlet is below the 344 kPa (50 psi) MIN specification and new primary or secondary fuel filters have not been installed, install new primary and secondary fuel filters. Repeat the Fuel Conditioning Module Pressure test to verify the repair.

If the Fuel Conditioning Module Pressure test has been repeated and the fuel pressure at the fuel conditioning module outlet now meets the 344 kPa (50 psi) MIN specification, remove the fuel return line plugs and connect the fuel return line. Repeat the Fuel System Delivery test to verify the repair.

If the Fuel Conditioning Module Pressure test has been repeated and the fuel pressure at the fuel conditioning module outlet is still below the 344 kPa (50 psi) MIN specification, carry out the Electric Fuel Pump Inlet Restriction test.

If the fuel pressure at the fuel conditioning module outlet is equal to or greater than the 344 kPa (50 psi) MIN specification, carry out the Restricted Secondary Fuel Filter test.