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Diagnostic Test

  1. CHECK FUEL DELIVERY SYSTEM FOR LEAKS AND DAMAGE 
    WARNING:

    The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting, or line, the fuel system pressure must be released. Failure to follow these instructions can result in possible serious or fatal injury.

    1. Visually and physically inspect the fuel delivery system for external leaks and damage.

      Is the system leaking or damaged?

      Yes 

      • Repair or replace as necessary.
      • Perform the PCM VERIFICATION TEST. Refer to STANDARD PROCEDURE .

      No 

      • Go To  2
  2. INSTALL APPROPRIATE FUEL LINE ADAPTERS / FITTING FROM THE GAS AND DIESEL FUEL PRESSURE/DECAY TESTER 8978A 
    Fig 1: Fuel Line Adapters/Fitting
    GC0094811Courtesy of CHRYSLER GROUP, LLC
    1. Turn the ignition off.
      WARNING:

      The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting, or line, the fuel system pressure must be released. Failure to follow these instructions can result in possible serious or fatal injury.

    2. Disconnect the frame rail fuel supply line connector between the fuel supply line and the fuel rail.
    3. Install the appropriate Fuel Line Adapters / Fitting from the Gas and Diesel Fuel Pressure/Decay Tester (special tool #8978A, Decay Tool, Fuel).

      Proceed 

      • Go To  3
  3. INSTALL FUEL PRESSURE GAUGE ASSEMBLY 
    Fig 2: Identifying Fuel Pressure Gauge Assembly
    GC0082754Courtesy of CHRYSLER GROUP, LLC
    WARNING:

    The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting, or line, the fuel system pressure must be released. Failure to follow these instructions can result in possible serious or fatal injury.

    1. Connect Fuel Pressure Gauge Assembly (special tool #8978A, Decay Tool, Fuel), Fuel Inlet Hose (1) and Fuel Outlet Hose (2) to the Fuel Line Adapters / Fitting.
    2. Connect special tool Drain Extension Hose 535680 (3) to the Fuel Pressure Gauge Assembly Drain Hose (5).
    3. Connect Reservoir Assembly 534960 (4) to Drain Extension Hose 535680 (3).
      WARNING:

      To reduce the risk of fire and possible serious or fatal injury, place Reservoir Assembly 534960 (4) on the floor and out of the way so that it is not a trip hazard.

      Proceed 

      • Go To  4
  4. CHECK FUEL PRESSURE 
    Fig 3: Identifying Fuel System Isolation Valve & Flow Test Valves
    GC0082755Courtesy of CHRYSLER GROUP, LLC
    WARNING:

    The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting, or line, the fuel system pressure must be released. Failure to follow these instructions can result in possible serious or fatal injury.

    1. Perform the following procedure to purge air from the system:
      • Open the Fuel System Isolation Valve (1).
      • Close the Flow Test Valve (2).
      • Ignition on, engine not running.
      • With the scan tool, actuate the fuel pump.
      • Open the Flow Test Valve (1) for 10 seconds, then close the Valve.
      • CAUTION: Stop All Actuations. 
      • Turn the ignition off.
      • Disconnect, empty and then reconnect the Reservoir Assembly.
    2. Turn the ignition on, wait five seconds, turn the ignition off and then wait one minute before proceeding.
    3. Read the Fuel Pressure Gauge (3) and record the reading. The fuel pressure specification is 407 kPa +/- 34 kPa (59 psi +/- 5 psi).

      Is the fuel pressure within specifications?

      Yes 

      • Go To  5

      No 

  5. CHECK FUEL DELIVERY SYSTEM OUTPUT 
    Fig 4: Identifying Flow Test Valve And Reservoir Assembly
    GC0094812Courtesy of CHRYSLER GROUP, LLC
    WARNING:

    The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting, or line, the fuel system pressure must be released. Failure to follow these instructions can result in possible serious or fatal injury.

    1. Ignition on, engine not running.
    2. With the scan tool, actuate the fuel pump.
    3. Open the Flow Test Valve (1) for 20 seconds, then close the Valve.
      CAUTION:

      Stop all actuations.

    4. Turn the ignition off.
    5. Measure the amount of fuel in the Reservoir Assembly (2). The fuel output specification is ml/s X 20 seconds = fuel flow in ml.
      FUEL FLOW
      ENGINE ml/s ml per 20 Seconds
      4 Cylinder and 6 Cylinder 20.8333A 417
      8 Cylinder 38.88889 778

      Does the amount of fuel in the reservoir meet or exceed the specification?

      Yes 

      • Test complete.

      No 

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