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Pressure Relief - Fuel System

Special Tool(s) 

Fig 1: Identifying Special Tool
G03453876Courtesy of FORD MOTOR CO.
WARNING: The fuel system operates under high pressure and remains pressurized after engine shutdown. The fuel system pressure must be relieved before any fuel-related components are serviced. Failure to relieve the fuel pressure could result in personal injury or property damage.
WARNING: The status (stuck open, stuck closed, or good) of each fuel tank solenoid valve must be identified prior to venting the fuel system or personal injury or property damage may result. For additional information, refer to Diagnosis and Testing in FUEL TANK & LINES-NATURAL GAS .
WARNING: Do not vent an entire fuel tank by using the fuel line venting procedure, as damage to the fuel supply manifold Schrader valve will result, with the possibility of personal injury or property damage.
WARNING: Do not modify the system configuration or components, or install components or parts not specially designed for use with natural gas. Ford Motor Company has specially designed the materials, components and system configuration for the 4.6L Crown Victoria natural gas vehicles, and each particular system is precisely calibrated for efficient operation. The use of different parts or materials can produce an untested configuration that could result in fire or personal injury, or cause engine damage.
WARNING: Eye and ear protection are required to be worn during venting or removal and installation of fuel system components. Failure to follow these instructions may result in personal injury.
CAUTION: Do not vent any fuel tank unless the fuel tank or the fuel tank solenoid valve is damaged or inoperative and a new fuel tank solenoid valve or fuel tank must be installed. Unnecessary venting of good tanks can cause damage to the fuel tank solenoid valve.
NOTE: The following venting procedures must be used when removal of the fuel tanks or fuel tank solenoid valves is required for the installation of new fuel tanks or fuel tank solenoid valves.
NOTE: It is recommended that venting be carried out with a vent stack. A typical vent stack installation is shown in DESCRIPTION AND OPERATION . This is a typical installation only. Any vent stack installation must be approved by local authorities.
NOTE: The following procedures are based on the fuel tank solenoid valves status. Refer to Diagnosis and Testing in FUEL TANK & LINES-NATURAL GAS to determine the individual fuel tank solenoid valve status. Based on the results of the solenoid status found, follow the appropriate procedure for either fuel tank solenoid valves normal, stuck open or stuck closed.
NOTE: The pressure relief procedure to be followed depends on the component(s) being serviced, what component(s) may be damaged or inoperative, or at what point in fuel system procedures you are referenced to this procedure. The status of the fuel tank solenoid valves is the most critical factor in determining the correct fuel system pressure relief procedures to follow. Pressure relief procedures are fuel line venting and fuel tank venting, with fuel tank venting having three parts depending on fuel tank solenoid status.
NOTE: The fuel line venting procedure is accomplished at the Schrader valve fitting on the fuel injection supply manifold. This will vent the fuel lines from the fuel supply manifold to the fuel tank solenoids (or the quarter-turn valve if it is closed). It is required prior to installation of any fuel system component, since the fuel pressure regulator is not designed to backflow reliably. This procedure is used either in conjunction with the fuel tank venting procedure to make sure of complete fuel system pressure relief, or on its own if the fuel tank solenoid status is good or the quarter-turn valve is closed. Any fuel system component downstream of the fuel tank solenoid valves (or the quarter-turn valve if closed) may be serviced. This includes the fuel supply manifold and its related components, the fuel shutoff valve solenoid, the coalescer/filter assembly, the fuel pressure regulator, and all the fuel lines if the fuel tank solenoid status is good or the low pressure fuel lines if the quarter-turn valve is closed.
NOTE: The fuel tank venting procedure is accomplished at the fuel fill valve and should only be carried out when a damaged, expired, or inoperative fuel tank or fuel tank solenoid valve is detected. The fuel tank venting must be confirmed with the use of the Rotunda Manual Override Tool 134-00050 (or equivalent). Once the override tool has been used, a new fuel tank solenoid must be installed, as the use of the override tool will destroy the solenoid valve. This procedure must be carried out to vent any fuel tank with a stuck open or stuck closed solenoid valve or to vent any fuel tank for any reason.
NOTE: The special tools required for these procedures are also available in a kit form that comes with all the tools needed to service the CNG Crown Victoria. The kit is the Rotunda Natural Gas (NGV) Pressure Test and Venting Kit, 134-00114.
NOTE: It is recommended that venting be carried out with a vent stack. A typical vent stack installation is shown in the DESCRIPTION AND OPERATION . This is a typical installation only. Any vent stack installation must be approved by local authorities.

    FUEL LINE VENTING 

  1. Disconnect the battery ground cable. For additional information, refer to BATTERY, MOUNTING AND CABLES .
  2. Connect the Grounding Cable to the fuel injection supply manifold.
    Fig 2: Connecting Grounding Cable To Fuel Injection Supply Manifold
    G03453877Courtesy of FORD MOTOR CO.
  3. Connect the Grounding Cable to the ground rod.
    Fig 3: Connecting Grounding Cable To Ground Rod
    G03453878Courtesy of FORD MOTOR CO.
    4. NOTE: Make sure that the bleed valve on the Fuel Rail Pressure Test and Venting Kit is closed.
    Fig 4: Connecting Fuel Rail Pressure Test And Venting Kit
    G03453879Courtesy of FORD MOTOR CO.
  4. Connect the Fuel Rail Pressure Test and Venting Kit to the fuel injection supply manifold Schrader valve and to the Venting Hose Assembly.
  5. Connect the Venting Hose Assembly to the vent stack.
    Fig 5: Connecting Venting Hose Assembly To Vent Stack
    G03453880Courtesy of FORD MOTOR CO.
    6. NOTE: If after venting the fuel lines for approximately one minute the pressure test gauge still registers normal fuel system pressure at this point (95-125 psi), refer to Diagnosis and Testing in FUEL TANK & LINES-NATURAL GAS to determine fuel tank solenoid status.
  6. Slowly open the bleed valve on the Fuel Rail Pressure Test and Venting Kit and allow the contents of the fuel lines to vent to atmosphere for one minute.
  7. Close the bleed valve on the Fuel Rail Pressure Test and Venting Kit and remove from the vehicle.

    8. FUEL TANK VENTING-SOLENOID VALVES, FUNCTIONS NORMALLY 

    NOTE: Solenoid diagnostics must be completed on all tank solenoid valves prior to venting.
    NOTE: Vent the individual fuel tanks as necessary. Disconnect the electrical connectors and tighten the manual lock-down jackscrews to 9 Nm (80 lb.-in.) on the fuel tanks not to be vented. The vent box on the rear or upper fuel tank rack will need to be removed to access the upper fuel tank rack solenoid jackscrews and individual upper fuel tank solenoid electrical connectors. For additional information, refer to FUEL TANK & LINES-NATURAL GAS . If neither of the rear or upper fuel tanks needs to be vented, the rear/upper fuel tank rack harness connector C420F may be disconnected without removing the rear or upper fuel tank rack vent box.
    Fig 6: Connecting Grounding Cable To Back Side Of Fuel Fill Valve
    G03453881Courtesy of FORD MOTOR CO.
  8. Connect the Grounding Cable to the back side of the fuel fill valve at the fuel line connection.
  9. Connect the Grounding Cable to the ground rod.
    Fig 7: Connecting Grounding Cable To Ground Rod
    G03453882Courtesy of FORD MOTOR CO.
    10. NOTE: Make sure the manual bleed valve on the Fuel Filler Neck Venting Kit is closed prior to connecting to the fuel filler valve.
    Fig 8: Connecting Fuel Filler Neck Venting Kit To Fuel Filler Valve
    G03453883Courtesy of FORD MOTOR CO.
  10. Connect the Fuel Filler Neck Venting Kit to the fuel filler valve.
  11. Connect the Venting Hose Assembly to the Fuel Filler Neck Venting Kit.
    Fig 9: Connecting Venting Hose Assembly To Fuel Filler Neck Venting Kit
    G03453884Courtesy of FORD MOTOR CO.
  12. Connect the Venting Hose Assembly to the vent stack.
    Fig 10: Connecting Venting Hose Assembly To Vent Stack
    G03453885Courtesy of FORD MOTOR CO.
  13. Remove the fuel valve relay from the power distribution box.
  14. Construct a jumper wire from 152 mm (6 inches) of 18 gauge wire and two spade terminal ends.
    15. NOTE: This step will supply power and open the fuel tank solenoid valves that have their electrical connectors connected.
    Fig 11: Identifying Jumper Fuel Valve Relay Circuit From Socket
    G03453886Courtesy of FORD MOTOR CO.
  15. Jumper the fuel valve relay circuit from Socket 87 to Socket 30.
  16. Slowly open the manual backflow valve on the fuel filler valve with a 3/16" Allen wrench.
    Fig 12: Identifying Manual Backflow Valve On Fuel Filler Valve
    G03453887Courtesy of FORD MOTOR CO.
  17. Observe the gauge pressure of the Fuel Filler Neck Venting Kit. The pressure should be at tank pressure if the fuel tank solenoid valve was identified as functions normally.
  18. Slowly open the bleed valve on the Fuel Filler Neck Venting Kit and allow the contents of the fuel tank to vent to atmosphere. Venting may take in excess of one hour.
  19. Close the bleed valve on the Fuel Filler Neck Venting Kit and observe the gauge pressure. The pressure should be at or near 0 kPa (0 psi).
  20. Remove the fuel tank solenoid manual lock-down valve.
    Fig 13: Removing Fuel Tank Solenoid Manual Lock-Down Valve
    G03453888Courtesy of FORD MOTOR CO.
    21. WARNING: Make sure the jackscrew in the Manual Override Tool is retracted fully (counterclockwise) prior to installation into the fuel tank solenoid valve. Installation of the Manual Override Tool in the venting position will cause natural gas to be immediately released which may result in personal injury or property damage.
    CAUTION: The solenoid valve must be discarded after these procedures as the use of the Manual Override Tool will destroy the solenoid valve.
    Fig 14: Installing Manual Override Tool Into Fuel Tank Solenoid
    G03453889Courtesy of FORD MOTOR CO.
  21. Install the Manual Override Tool into the fuel tank solenoid of the tank to be vented.
  22. Turn in the Manual Override Tool jackscrew until fuel flows.
    Fig 15: Turning In Manual Override Tool Jackscrew
    G03453890Courtesy of FORD MOTOR CO.
  23. Vent the fuel tank until the fuel flow stops.
  24. Close the manual backflow valve on the fuel filler valve when the tank contents have been vented.
    Fig 16: Closing Manual Backflow Valve On Fuel Filler Valve
    G03453891Courtesy of FORD MOTOR CO.
  25. Carry out the fuel line venting procedure. For additional information, refer to Fuel Line Venting under PRESSURE RELIEF - FUEL SYSTEM .
  26. Remove the Manual Override Tool from the fuel tank solenoid valve.
    Fig 17: Removing Manual Override Tool From Fuel Tank Solenoid Valve
    G03453892Courtesy of FORD MOTOR CO.
  27. Install the fuel tank solenoid manual lock-down valve.
    Fig 18: Installing Fuel Tank Solenoid Manual Lock-Down Valve
    G03453893Courtesy of FORD MOTOR CO.
  28. Turn in the manual lock-down valve jackscrew on the fuel tank solenoid valve.
    Fig 19: Turning In Manual Lock-Down Valve Jackscrew On Fuel Tank Solenoid Valve
    G03453894Courtesy of FORD MOTOR CO.
  29. Repeat the procedure until all affected tanks are vented.

    30. SOLENOID VALVES-STUCK OPEN 

    NOTE: Solenoid diagnostics must be completed on all tank solenoid valves prior to venting.
    NOTE: Vent the individual fuel tanks that the fuel tank solenoid valve(s) were identified as stuck open as necessary. Disconnect the electrical connectors and tighten the manual lock-down jackscrews to 9 Nm (80 lb.-in.) on the fuel tanks not to be vented. The vent box on the upper fuel tank rack will need to be removed to access the upper fuel tank rack solenoid jackscrews and individual upper fuel tank solenoid electrical connectors. For additional information, refer to FUEL TANK & LINES-NATURAL GAS . If the rear or the upper fuel tank needs to be vented, the rear/upper fuel tank rack harness connector C420F may be disconnected without removing the rear/upper fuel tank rack vent box.
    Fig 20: Connecting Grounding Cable To Back Side Of Fuel Fill Valve
    G03453895Courtesy of FORD MOTOR CO.
  30. Connect the Grounding Cable to the back side of the fuel fill valve at the fuel line connection.
  31. Connect the Grounding Cable to the ground rod.
    Fig 21: Connecting Grounding Cable To Ground Rod
    G03453896Courtesy of FORD MOTOR CO.
    32. NOTE: Make sure the manual bleed valve on the Fuel Filler Neck Venting Kit is closed prior to connecting to the fuel filler valve.
    Fig 22: Connecting Fuel Filler Neck Venting Kit To Fuel Filler Valve
    G03453897Courtesy of FORD MOTOR CO.
  32. Connect the Fuel Filler Neck Venting Kit to the fuel filler valve.
  33. Connect the Venting Hose Assembly to the Fuel Filler Neck Venting Kit.
    Fig 23: Connecting Venting Hose Assembly To Fuel Filler Neck Venting Kit
    G03453898Courtesy of FORD MOTOR CO.
  34. Connect the Venting Hose Assembly to the vent stack.
    Fig 24: Connecting Venting Hose Assembly To Vent Stack
    G03453899Courtesy of FORD MOTOR CO.
  35. Slowly open the manual backflow valve on the fuel filler valve.
    Fig 25: Installing Manual Backflow Valve On Fuel Filler Valve
    G03453900Courtesy of FORD MOTOR CO.
  36. Observe the gauge pressure of the Fuel Filler Neck Venting Kit. The pressure should be at tank pressure if the fuel tank solenoid valve was identified as stuck open.
  37. Slowly open the bleed valve on the Fuel Filler Neck Venting Kit and allow the contents of the fuel tank to vent to atmosphere. Venting may take in excess of one hour.
  38. Close the bleed valve on the Fuel Filler Neck Venting Kit, and observe the gauge pressure. The pressure should be at or near 0 kPa (0 psi).
  39. Remove the fuel tank solenoid manual lock-down valve.
    Fig 26: Removing Fuel Tank Solenoid Manual Lock-Down Valve
    G03453901Courtesy of FORD MOTOR CO.
    40. WARNING: Make sure the jackscrew in the Manual Override Tool is retracted fully (counterclockwise) prior to installation into the fuel tank solenoid valve. Installation of the Manual Override Tool in the venting position will cause natural gas to be immediately released which may result in personal injury or property damage.
    CAUTION: The solenoid valve must be discarded after these procedures as the use of the Manual Override Tool will destroy the solenoid valve.
    Fig 27: Installing Manual Override Tool Into Fuel Tank Solenoid
    G03453902Courtesy of FORD MOTOR CO.
  40. Install the Manual Override Tool into the fuel tank solenoid of the tank to be vented.
  41. Turn in the Manual Override Tool jackscrew until fuel flows.
    Fig 28: Turning In Manual Override Tool Jackscrew
    G03453903Courtesy of FORD MOTOR CO.
  42. Open the manual bleed valve on the Fuel Filler Neck Venting Kit and vent the fuel tank until the fuel flow stops.
  43. Close the manual backflow valve on the fuel filler valve when the tank contents have been vented.
    Fig 29: Closing Manual Backflow Valve On Fuel Filler Valve
    G03453904Courtesy of FORD MOTOR CO.
  44. Carry out the fuel line venting procedure. For additional information, refer to Fuel Line Venting under PRESSURE RELIEF - FUEL SYSTEM .
  45. Remove the Manual Override Tool from the fuel tank solenoid valve.
    Fig 30: Removing Manual Override Tool From Fuel Tank Solenoid Valve
    G03453905Courtesy of FORD MOTOR CO.
  46. Install the fuel tank solenoid manual lock-down valve.
    Fig 31: Installing Fuel Tank Solenoid Manual Lock-Down Valve
    G03453906Courtesy of FORD MOTOR CO.
  47. Turn in the manual lock-down valve jackscrew on the fuel tank solenoid valve.
    Fig 32: Turning In Manual Lock-Down Valve Jackscrew On Fuel Tank Solenoid Valve
    G03453907Courtesy of FORD MOTOR CO.
  48. Repeat the procedure until all affected tanks are vented.

    49. SOLENOID VALVES-STUCK CLOSED 

    NOTE: Solenoid diagnostics must be completed on all tank solenoid valves prior to venting.
    NOTE: Vent the individual fuel tanks that the fuel tank solenoid valve(s) were identified as stuck closed as necessary. Disconnect the electrical connectors and tighten the manual lock-down jackscrews to 9 Nm (80 lb.-in.) on the fuel tanks not to be vented. The vent box on the upper fuel tank rack will need to be removed to access the upper fuel tank rack solenoid jackscrews and individual upper fuel tank solenoid electrical connectors. For additional information, refer to FUEL TANK & LINES-NATURAL GAS . If neither of the upper fuel tanks needs to be vented, the upper fuel tank rack harness connector C420F may be disconnected without removing the upper fuel tank rack vent box.
    Fig 33: Connecting Grounding Cable To Back Side Of Fuel Fill Valve
    G03453908Courtesy of FORD MOTOR CO.
  49. Connect the Grounding Cable to the back side of the fuel fill valve at the fuel line connection.
  50. Connect the Grounding Cable to the ground rod.
    Fig 34: Connecting Grounding Cable To Ground Rod
    G03453909Courtesy of FORD MOTOR CO.
    51. NOTE: Make sure the manual bleed valve on the Fuel Filler Neck Venting Kit is closed prior to connecting to the fuel filler valve.
    Fig 35: Connecting Fuel Filler Neck Venting Kit To Fuel Filler Valve
    G03453910Courtesy of FORD MOTOR CO.
  51. Connect the Fuel Filler Neck Venting Kit to the fuel filler valve.
  52. Connect the Venting Hose Assembly to the Fuel Filler Neck Venting Kit.
    Fig 36: Connecting Venting Hose Assembly To Fuel Filler Neck Venting Kit
    G03453911Courtesy of FORD MOTOR CO.
  53. Connect the Venting Hose Assembly to the vent stack.
    Fig 37: Connecting Venting Hose Assembly To Vent Stack
    G03453912Courtesy of FORD MOTOR CO.
  54. Open the manual bleed valve on the Fuel Filler Neck Venting Kit for one minute to bleed residual fuel system pressure. Close the manual bleed valve on the Fuel Filler Neck Venting Kit.
  55. Remove the manual lock-down valve from the fuel tank solenoid valve of the fuel tank to be vented.
    Fig 38: Removing Manual Lock-Down Valve From Fuel Tank Solenoid Valve
    G03453913Courtesy of FORD MOTOR CO.
    56. WARNING: Make sure the jackscrew in the Manual Override Tool is retracted fully (counterclockwise) prior to installation into the fuel tank solenoid valve. Installation of the Manual Override Tool in the venting position will cause natural gas to be immediately released which may result in personal injury or property damage.
    CAUTION: The solenoid valve must be discarded after these procedures as the use of the Manual Override Tool will destroy the solenoid valve.
    Fig 39: Installing Manual Override Tool Into Fuel Tank Solenoid Valve
    G03453914Courtesy of FORD MOTOR CO.
  56. Install the Manual Override Tool into the fuel tank solenoid valve of the tank to be vented.
  57. 57.  Turn in the Manual Override Tool jackscrew until fuel flows.
    Fig 40: Turning In Manual Override Tool Jackscrew
    G03453915Courtesy of FORD MOTOR CO.
  58. Slowly open the manual backflow valve on the fuel filler valve and observe the gauge pressure of the Fuel Filler Neck Venting Kit. The pressure reading should be at tank pressure.
    Fig 41: Opening Manual Backflow Valve On Fuel Filler Valve
    G03453916Courtesy of FORD MOTOR CO.
  59. Slowly open the bleed valve on the Fuel Filler Neck Venting Kit and allow the contents of the fuel tank to vent to atmosphere. Venting may take in excess of one hour.
  60. Vent the fuel tank until the fuel flow stops.
  61. Close the manual backflow valve on the fuel filler valve when the tank contents have been vented.
    Fig 42: Closing Manual Backflow Valve On Fuel Filler Valve
    G03453917Courtesy of FORD MOTOR CO.
  62. Carry out the fuel line venting procedure. For additional information, refer to Fuel Line Venting under PRESSURE RELIEF - FUEL SYSTEM .
  63. Remove the Manual Override Tool from the fuel tank solenoid valve.
    Fig 43: Removing Manual Override Tool From Fuel Tank Solenoid Valve
    G03453918Courtesy of FORD MOTOR CO.
  64. Install the fuel tank solenoid manual lock-down valve.
    Fig 44: Installing Fuel Tank Solenoid Manual Lock-Down Valve
    G03453919Courtesy of FORD MOTOR CO.
  65. Turn in the manual lock-down valve jackscrew on the fuel tank solenoid valve.
    Fig 45: Turning In Manual Lock-Down Valve Jackscrew On Fuel Tank Solenoid Valve
    G03453920Courtesy of FORD MOTOR CO.
  66. Repeat the procedure until all affected tanks are vented.
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