10b. Electric Fuel Pump Inlet Restriction

10b. Electric Fuel Pump Inlet Restriction

WARNING: AVOID CONTACT WITH FUEL DURING A VISUAL INSPECTION FOR FUEL LEAKS WITH THE ENGINE RUNNING. DO NOT WORK ON THE FUEL SYSTEM UNTIL THE PRESSURE HAS BEEN RELEASED AND THE ENGINE HAS COOLED. FUEL IN THE HIGH- PRESSURE FUEL SYSTEM IS HOT AND UNDER VERY HIGH PRESSURE. HIGH-PRESSURE FUEL MAY CAUSE CUTS AND CONTACT WITH HOT FUEL MAY CAUSE BURNS. FAILURE TO FOLLOW THESE INSTRUCTIONS MAY RESULT IN SERIOUS PERSONAL INJURY.

WARNING: WHEN HANDLING FUEL, ALWAYS OBSERVE FUEL HANDLING PRECAUTIONS AND BE PREPARED IN THE EVENT OF FUEL SPILLAGE. SPILLED FUEL MAY BE IGNITED BY HOT VEHICLE COMPONENTS OR OTHER IGNITION SOURCES. FAILURE TO FOLLOW THESE INSTRUCTIONS MAY RESULT IN SERIOUS PERSONAL INJURY.

Note: The Diesel Fuel Flow Tester 310-193 or equivalent provides a pressure reading while simulating maximum fuel consumption at full load on the fuel system. The Diesel Fuel Flow Tester 310-193 uses a 1.193 mm (0.047 in) calibrated orifice integrated in the tool assembly to simulate the fuel consumption.

Note: Make sure the battery voltage is greater than 12.5 volts at all times throughout this procedure. Install a battery charger if necessary. Fuel pumps will not pass the fuel delivery tests if the battery voltage drops below 12.5 volts during the fuel flow tests. This is especially important if the test is carried out on a non-running vehicle because there are significant electrical loads when operating the fuel pump with the engine off If the battery voltage drops below 12.5 volts the battery may need to be charged or there may be a charging system concern refer to Charging System Symptom Chart to continue diagnosis.

Purpose:

To detect concerns with the fuel conditioning module inlet fuel filters or fuel pump.

Electric Fuel Pump Inlet Restriction

Measure the fuel inlet vacuum on the fuel tank side of the fuel conditioning module.






Recommended Procedure:

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

^ Verify there is fuel in the tank.
^ Verify the fuel temperature is above 0 °C or 32 °F to prevent testing with gelled fuel. Check for sufficient clean fuel carry out the Sufficient Clean Fuel test in this section.
^ Make sure the valve on the Diesel Fuel Flow Tester 310-193 or equivalent is closed.

^ NOTICE: Correct installation of the Diesel Fuel Flow Tester 310-193 or equivalent is necessary to prevent damage to the interior of the vehicle.

Remove the test port plug from the front of the secondary fuel filter housing. Install the Diesel Fuel Flow Tester 310-193 or equivalent using two new sealing washers to seal the banjo bolt and torque to 27 Nm (20 lb-fl).






^ Insert the heavy duty black end of the clear yellow hose into the fuel tank filler pipe to drain the fuel into the fuel tank. Make sure the fuel return hose is not pinched or restricted. Do not substitute any other fuel return hose and do not change the hose length of 6.7 m (22 ft) clear yellow hose with 0.91 m (3 ft) heavy duty black hose end or the internal diameter (ID) of 6.35 mm (0.25 in). The heavy duty black end on the hose is used to reduce pinching between the fuel filler door and the vehicle body.
^ If directed to this test from the Fuel System Delivery test remove the Adapter Fuel Pressure Test 310-111 or equivalent and the Gauge 0-1100 kPa (0-160 psi) Bar (part of DSL ENG Pressure Test Kit 014-00761 or equivalent) from the fuel conditioning module outlet fuel supply line. Connect the fuel conditioning module outlet fuel supply line to the fuel conditioning module outlet port.
^ Install the Adapter Fuel Pressure Test 310-111 or equivalent with the 0-30 in-Hg Vacuum Gauge (part of DSL ENG Pressure Test Kit 014-00761 or equivalent) between the fuel supply line and the fuel conditioning module inlet port.






^ 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.
^ 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 air bubbles can not be purged check for kinks or leaks.
^ 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 Charging System for diagnosis as necessary.
^ Record the indicated vacuum reading while the valve is open and fuel is flowing back to the fuel tank.

If the vacuum reading is greater than the specification correct the restriction between the fuel tank pickup and the fuel conditioning module remove the fuel return line plugs and connect the fuel return line. Repeat the Fuel System Delivery test in this section to verify the repair.

If the vacuum reading is less than the specification check the primary fuel filter. If the primary fuel filter is OK install a new fuel conditioning module refer to Fuel Tank and Lines Fuel Conditioning Module. Remove the fuel return line plugs connect the fuel return line and repeat the Fuel System Delivery test in this section to verify the repair.

Possible Causes:

^ Fuel supply line restriction
^ Fuel conditioning module
^ In tank fuel pickup

Tools Required:

Diesel Fuel Flow Tester 310-193 or equivalent

Adapter Fuel Pressure Test 310-111 or equivalent

0-30 in-Hg Vacuum Gauge (part of DSL ENG Pressure Test Kit 014-00761 or equivalent)