Fuel System-General Information-Natural Gas Ford Crown Victoria II

FUEL SYSTEM TORQUE SPECIFICATIONS

FUEL SYSTEM TORQUE SPECIFICATIONS

Note. It is important that your natural gas vehicle be correctly maintained by Ford natural gas trained personnel. If a problem occurs, it is important that correctly trained personnel diagnose the cause. If the problem relates to the fuel system, correct new part installation is imperative to keep your vehicle operating at normal performance. Natural gas components and gasoline fuel components are not interchangeable. If your vehicle is not serviced in accordance with natural gas-fueled vehicle procedures, damage can occur and your warranty may be invalidated.

Note. All standard production components and systems receive routine service under base warranty procedures.

When servicing the fuel system, observe the following information

1. All 4.6L CNG engines use a closed-type positive crankcase ventilation (PCV) system and an exhaust emission system to control engine emissions within government specifications.
2. To maintain the required exhaust emission levels, the fuel system must be kept in correct operating condition.
3. The natural gas fuel system must be adjusted to specifications.
4. Additional engine performance checks are required to keep the exhaust emissions at the specified minimum pollutant level.

This article covers general procedures related directly to the fuel system.

Fuel Tank Solenoid Valve

The fuel tank solenoid valves are located on each fuel tank, one per fuel tank. The solenoid valve is a normally closed valve that opens when energized. With the key off, each solenoid valve is closed to isolate the fuel tanks from the rest of the fuel system. The solenoid valves are wired on the same circuit that a gasoline vehicle would use for the fuel pump. The circuit uses the inertia fuel shutoff (IFS) switch just as a gasoline fuel pump would, opening the circuit if the IFS switch opens. During fueling, the solenoid valve acts as a check valve and allows fuel flow into the fuel tank due to the pressure differential between the fuel being added at the fill station and the fuel tank internal pressure. The solenoid valve has the capability of being manually locked down through the solenoid valve manual lock-down jackscrew located on the solenoid valve. This feature provides an extra measure of safety when service of the fuel system becomes necessary, as well as providing a means to isolate each individual fuel tank from the rest of the system.

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Fuel Pressure Regulator-Coalescer/Filter Assembly

Natural gas vehicles are equipped with a fuel pressure regulator-coalescer/filter assembly. The coalescer/filter assembly separates, filters and stores any contamination and moisture found in the fuel system, preventing moisture from entering the engine. The filter can be disassembled to service the filter element. The drain plug on the bottom of the housing allows the draining of water that has accumulated in the fuel system. The filter should be drained at regular intervals, such as each oil change. The fuel pressure regulator is a single stage pressure reducing regulator which takes the natural gas from tank pressure of 1,379 to 20,685 kPa (200 to 3,000 psi) and regulates it to engine fuel injector pressure of 724 to 862 kPa (105 to 125 psi). When reducing the pressure, the fuel temperature drops significantly, causing extremely cold temperatures of -177°C (-160°F) that may damage fuel system components as well as causing water vapor present in the fuel to condense and freeze, plugging up the fuel system. Engine coolant is circulated to the fuel pressure regulator to prevent this by warming the fuel.

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Typical Vent Stack Installation

Refer to the following illustration for a typical vent stack installation.

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Fuel Tank Location and Arrangement

Refer to the following illustration for the fuel tank installation.

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For fuel system diagnosis, refer to INTRODUCTION - CNG, FLEX-FUEL & GASOLINE .

For fuel tank and fuel tank solenoid diagnosis, refer to FUEL TANK, LINES AND ELECTRIC FUEL SOLENOID VALVES .

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Note. It is recommended that venting be performed with a vent stack. A typical vent stack installation is shown in Typical Vent Stack Installation . This is a typical installation only. Any vent stack installation must be approved by local authorities.

Note. The following procedures are required to be used when venting fuel from the fuel lines to remove the fuel tanks, the fuel lines, the coalescer/filter assembly, the fuel pressure regulator, the fuel injection supply manifold, the fuel injectors, the fuel pressure relief valve, the fuel shutoff valve solenoid, the injection pressure sensor or the engine fuel temperature sensor.

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1. Close each manual lock-down valve jackscrew on the fuel tank solenoid valves.
2. Disconnect the fuel rail pressure (FRP) sensor electrical connector.
3. Start the engine and allow it to idle until it stalls. Once the engine stalls, crank the engine for an additional 15 seconds.
4. Slightly loosen the FRP sensor to release the residual pressure from the fuel rail.
5. Tighten and reconnect the FRP sensor.
6. Using the scan tool, access the FRP PID. The FRP PID should indicate less than 5 psi. If so, the fuel system may be opened and serviced. If not, repeat the procedure.
7. Slightly loosen the low pressure fuel line fitting until the fuel starts to escape. After the fuel is evacuated, disconnect the fitting, install new O-rings, lubricate the O-rings with engine oil, and connect the fitting.

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Note. It is recommended that venting be performed with a vent stack. A typical vent stack installation is shown in Typical Vent Stack Installation . This is a typical installation only. Any vent stack installation must be approved by local authorities.

Note. Do not vent any fuel tank unless a new fuel tank or a new fuel tank solenoid valve is installed. Unnecessary venting of good tanks can cause damage to the fuel tank solenoid valve.

1. The following procedures are required to be used when venting fuel from the fuel tanks in order to remove fuel tanks.

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1. Turn in the manual lock-down valve jackscrew on the fuel tank solenoid valve(s).
2. Carry out the fuel line venting procedure. For additional information, REFER to «FUEL LINE EVACUATION»(/ford/crown-victoria/ii-1997-2011/remont/fuel-system/#fuel-system-general-information-natural-gas) .
3. Disconnect the fuel fill line from the fuel fill valve.
4. Connect the Fuel Venting Kit and Adapter to the fuel fill line.
5. Connect the Grounding Cable to the fuel fill line connection.
6. Connect the Grounding Cable to the ground rod.
7. Connect the Fuel Filler Neck Venting Kit to the Venting Hose Assembly and Adapter.
8. Connect the Fuel Venting Kit to the Fuel Filler Neck Venting Kit.
9. Connect the Venting Hose Assembly to the vent stack.
10. Remove the fuel pump relay from the power distribution box.
11. Construct a jumper wire from 152 mm (6 inches) of 18 gauge wire and two spade terminal ends.
12. Jumper the fuel pump relay circuit from Socket 87 to Socket 30.
13. Slowly open the manual lock-down valve jackscrew on the fuel tank solenoid valve of the fuel tank to be vented.
14. 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".
15. Slowly open the bleed valve on the venting kit and allow the contents of the fuel tank to vent to the atmosphere. Venting can take in excess of one hour.
16. Close the bleed valve on the venting kit, and observe the gauge pressure. The pressure should be at or near 0 kPa (0 psi).
17. Repeat the procedure until all affected tanks are vented.
18. Install the fuel fill line onto the fuel fill valve.

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1. Turn in the manual lock-down valve jackscrew on the fuel tank solenoid valve(s).
2. Carry out the fuel line venting procedure. For additional information, REFER to «FUEL LINE EVACUATION»(/ford/crown-victoria/ii-1997-2011/remont/fuel-system/#fuel-system-general-information-natural-gas) .
3. Disconnect the fuel fill line from the fuel fill valve.
4. Connect the Fuel Venting Kit and Adapter to the fuel fill line.
5. Connect the Grounding Cable to the fuel fill line connection.
6. Connect the Grounding Cable to the ground rod.
7. Connect the Fuel Filler Neck Venting Kit to the Venting Hose Assembly and Adapter.
8. Connect the Fuel Venting Kit to the Fuel Filler Neck Venting Kit.
9. Connect the Venting Hose Assembly to the vent stack.
10. Slowly open the manual lock-down valve jackscrew on the fuel tank solenoid valve of the fuel tank to be vented.
11. 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".
12. Slowly open the bleed valve on the venting kit and allow the contents of the fuel tank to vent to the atmosphere. Venting can take in excess of one hour.
13. Close the bleed valve on the venting kit, and observe the gauge pressure. The pressure should be at or near 0 kPa (0 psi).
14. Remove the fuel tank solenoid manual lock-down valve.
15. Install the Manual Override Tool into the fuel tank solenoid of the tank to be vented.
16. Turn in the override tool jackscrew until fuel flows.
17. Vent the fuel tank until the fuel flow stops.
18. Remove the override tool from the fuel tank solenoid valve.
19. Install the fuel tank solenoid manual lock-down valve.
20. Turn in the manual lock-down valve jackscrew on the fuel tank solenoid valve.
21. Repeat the procedure until all affected tanks are vented.
22. Install the fuel fill line onto the fuel fill valve.

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1. Turn in the manual lock-down valve jackscrew on the fuel tank solenoid valve(s).
2. Carry out the fuel line venting procedure. For additional information, REFER to «FUEL LINE EVACUATION»(/ford/crown-victoria/ii-1997-2011/remont/fuel-system/#fuel-system-general-information-natural-gas) .
3. Disconnect the fuel fill line from the fuel fill valve.
4. Connect the Fuel Venting Kit and Adapter to the fuel fill line.
5. Connect the Grounding Cable to the back side of the fuel fill valve at the fuel line connection.
6. Connect the Grounding Cable to the ground rod.
7. Connect the Fuel Filler Neck Venting Kit to the Venting Hose Assembly and Adapter.
8. Connect the Fuel Venting Kit to the Fuel Filler Neck Venting Kit.
9. Connect the Venting Hose Assembly to the vent stack.
10. Remove the manual lock-down valve from the fuel tank solenoid valve of the fuel tank to be vented.
11. Install the override tool into the fuel tank solenoid valve of the tank to be vented.
12. Slowly turn in the override tool jackscrew until fuel flows. Observe the gauge pressure of the Fuel Filler Neck Venting Kit. The pressure reading should be at tank pressure.
13. Slowly open the bleed valve on the venting kit and allow the contents of the fuel tank to vent to the atmosphere. Venting can take in excess of one hour.
14. Vent the fuel tank until the fuel flow stops.
15. Remove the override tool from the fuel tank solenoid valve.
16. Install the fuel tank solenoid manual lock-down valve.
17. Turn in the manual lock-down valve jackscrew on the fuel tank solenoid valve.
18. Repeat the procedure until all affected tanks are vented.
19. Install the fuel fill line onto the fuel fill valve.

Scheme 163

1. Relieve the fuel system pressure. For additional information, REFER to «FUEL LINE EVACUATION»(/ford/crown-victoria/ii-1997-2011/remont/fuel-system/#fuel-system-general-information-natural-gas) .
2. Raise the vehicle. For additional information, refer to «JACKING & LIFTING»(/ford/crown-victoria/ii-1997-2011/remont/hoistjack/#jacking-lifting) .
3. Place a container under the coalescer/filter assembly.
4. Slowly loosen the coalescer/filter assembly drain plug to vent the system of any residual fuel pressure.
5. Remove the coalescer/filter assembly drain plug and allow all liquid to drain.
6. Install the coalescer/filter assembly drain plug.
7. Carry out the fuel system leak test procedure. For additional information, REFER to «LEAK TEST»(/ford/crown-victoria/ii-1997-2011/remont/fuel-system/#fuel-system-general-information-natural-gas) .

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1. Relieve the fuel system pressure. For additional information, REFER to «FUEL LINE EVACUATION»(/ford/crown-victoria/ii-1997-2011/remont/fuel-system/#fuel-system-general-information-natural-gas) .
2. Remove the fuel tube clip.
3. Install the Spring Lock Coupling Disconnect Tool.
4. Close and push the Spring Lock Coupling Disconnect Tool into the open side of the cage.
5. Separate the fitting.
6. Remove the Spring Lock Coupling Disconnect Tool.

Connect

1. Push together the spring lock coupling fittings until the spring engages.

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1. Remove the fuel valve relay from the power distribution box.
2. Construct a jumper wire from 152 mm (6 inches) of 18 gauge wire and two spade terminal ends.
3. Jump the fuel valve relay circuit from Socket 87 to Socket 30.
4. Remove the jumper wire.
5. Install the fuel valve relay into the power distribution box.
6. Check the spring lock coupling and the fuel injection supply manifold to fuel injector connections for leaks using the Combustible Gas Detector (part of NGV Pressure Test and Venting Kit).
7. If a leak is detected, verify the connection is engaged correctly, then retest.
8. If the leak remains, repair as necessary and retest.

Fuel Tanks, Filter and Lines

1. Check the fuel tank(s), coalescer/filter and fuel line connections for leaks, using the Combustible Gas Detector.
2. If a leak is detected, verify that the fittings are tightened correctly, then retest.
3. If the leak remains, inspect the O-ring seal, O-ring seal land and sealing surfaces for any damage, distortion or contamination.
4. Repair as necessary and retest.

Scheme 173

1. Make the vapor vent box/tool connections. Install the Rotunda Pressure Test Adaptor 134-00122 (part of NGV Pressure and Venting Kit) or equivalent to the upper tank rack flexible vent tube. Install the Rotunda Evaporative Emission Tester 134-00056 or equivalent to the Pressure Test Adaptor.
2. Pressurize the vapor vent box to 5 kPa (17 inches H2O).
3. Monitor the pressure for two minutes. The pressure should not drop more than 1.5 kPa (6 inches H2O).
4. If the pressure drops in excess of 1.5 kPa (6 inches H2O), apply a soapy water solution around the vapor vent box gasket and seals to pinpoint the leak. Install a new gasket or seals as applicable.

Tank Inspection

1. Raise the vehicle. For additional information, refer to «JACKING & LIFTING»(/ford/crown-victoria/ii-1997-2011/remont/hoistjack/#jacking-lifting) .
2. Examine the vehicle underbody and chassis in the general area near the fuel tank(s) for any indication of collision damage, malfunction, fire or excessive mud/dirt accumulation.
3. Examine the fuel tank stone/heat shield for any indication of collision damage, malfunction, fire or excessive mud/dirt accumulation.
4. Remove the fuel tank stone/heat shield.
5. Examine the fuel tank(s) and the stone/heat shield interior for any foreign objects (such as stones or gravel) or foreign materials (such as mud, salt, liquids or chemical residue).
6. Remove any foreign material, using only a clean, dry cloth. Remove all foreign objects. Do not use water or any cleaners.
7. Examine the fuel tank labels for the tank expiration date. Use a light and mirror to access labels hidden from normal view. If the expiration date has been exceeded, condemn the tank using the procedure in Step 14 .
8. Inspect the tank sidewall and dome ends, following the general guidelines set forth in the Compressed Gas Association Pamphlet C6.4. Inspect the tank(s) for the following: abrasions dents cracking, blistering or peeling of clear coating corrosion cracks or gouges in the metal dome cracks in the fiberglass overwrap impact damage (crazing) in the fiberglass overwrap cuts or gouges in the fiberglass overwrap exposed fibers delamination (separating) of the fiberglass overwrap discoloration of the fiberglass overwrap fire or heat damage, such as charring or discoloration
9. If any flaws are detected, measure the depth and length of the flaw in accordance with the Compressed Gas Association Pamphlet C6.4 guidelines. If any of the flaws cannot be completely measured in the vehicle, the tank must be removed from the vehicle for further inspection.
10. If the tanks have been or are suspected of having been exposed to a corrosive chemical spill, the tank must be removed from the vehicle for further inspection of the complete composite surface, including the area under the tank straps. If there is any indication of chemical attack, such as blistering, cracking or delamination, the tanks must be condemned and new tanks must be installed. Tanks on the Natural Gas Crown Victoria are of an NGV2-2 design and do not have to be hydrostatically tested during their 15-year service life.
11. The acceptance criteria for cuts and abrasions are different from those listed in Section 6.5.1 of the Compressed Gas Association Pamphlet C6.4. The fuel tanks on the Crown Victoria have extra epoxy resin and a clear coat to reduce the sensitivity to surface damage. The following are the composite wrap inspection criteria: Level 1 abrasions: These are defined as minor abrasions, such as scuffs less than 0.254 mm (0.010 inch) deep, and are acceptable without repair. Level 2 abrasions: These are defined as abrasions having some exposed fibers or flat spots with a depth between 0.254 mm (0.010 inch) and 0.762 mm (0.030 inch). Level 2 abrasions must be repaired before the tank is returned to service. Level 1 cuts: These are defined as cuts or scratches less than 0.254 mm (0.010 inch) deep and are acceptable without repair regardless of length, number or direction. Level 2 cuts: These cuts have a maximum depth up to 0.762 mm (0.030 inch) and a maximum length up to 203 mm (8 inches). Level 2 cuts must be repaired before the tank is returned to service.
12. Repair of the damage to composite wrap is as follows: Level 2 cuts and abrasions are to be coated with epoxy resin. Mix and apply commercial room temperature cure, two-component epoxy resin according to the manufacturer's instructions. Frayed fibers must be cut away before application of the epoxy resin. Tanks with damage exceeding Level 2 must be condemned in accordance with Step 14 . The criteria for other damage to the composite wrap are defined in the Compressed Gas Association Pamphlet C6.4.
13. The metal tank ends are protected with a multi-coat system using epoxy and polyurethane coatings. Chips in the coating must be evaluated and repaired. The metal tank end external inspection criteria are as follows: Level 1 chips: These are chips or abrasions which do not penetrate the black epoxy coating. The steel or gray primer has not been exposed. Level 1 chips require no repair. Level 2 chips: These are chips or abrasions which penetrate the black epoxy coating and must be repaired as follows to prevent corrosion: Sand the damaged area to remove rust and rough up the surrounding coating. Clean the damaged area with a commercial pre-paint cleaning solvent. Apply a zinc-rich, cold galvanizing compound (Rust-Oleum ™ Zinc-Rich or equivalent commercial product). Dents: Tanks with dents to the metal ends which exceed 1.524 mm (0.060 inch) in depth must be removed from service and condemned. Gouges: Tanks with sharp gouges penetrating the coating and into the metal liner must be removed from service and condemned.
14. Condemned tanks, whether due to damage or expiration, shall be removed from the vehicle and destroyed as follows: Vent the fuel system. For additional information, REFER to «FUEL LINE EVACUATION»(/ford/crown-victoria/ii-1997-2011/remont/fuel-system/#fuel-system-general-information-natural-gas) . Remove the fuel tanks affected. For additional information, refer to «REMOVAL AND INSTALLATION»(/ford/crown-victoria/ii-1997-2011/remont/fuel-system/#fuel-tank-fuel-lines-natural-gas__removal-and-installation) . Remove the fuel tank solenoid valve. For additional information, refer to «SOLENOID VALVE»(/ford/crown-victoria/ii-1997-2011/remont/fuel-system/#fuel-tank-fuel-lines-natural-gas) . Purge the fuel tank with compressed air for 30 seconds. Destroy the fuel tank by drilling a 12.5 mm (0.5 inch) diameter hole in the fuel tank sidewall.
15. Fuel tank straps: Examine the fuel tank straps for correct positioning of the rubber isolators. Install new rubber isolators as necessary.
16. Remove the luggage compartment upper fuel tank rack trim panel and inspect the upper rack tanks as previously described. Notice any damage to the vapor vent box that may indicate damage to the upper fuel tanks.
17. Record the date, vehicle mileage and the results of the fuel tank inspection.

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1. Record the torque value to be obtained as A.
2. Measure the distance from the center of the torque wrench handgrip to the center of the torque wrench drive. Record this measurement as B.
3. Measure the distance from the center of the torque wrench adapter opening to the center of the torque wrench adapter drive. Record this measurement as C.
4. Example: multiply the torque value to be obtained A (120) by the length of the torque wrench B (12). Subtract the length of the torque wrench adapter C (2) from the length of the torque wrench B (12). Divide the product of A x B (1,440) by the difference of B - C (10) to obtain the torque multiplication conversion D (144).

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See also:
• INTRODUCTION - CNG, FLEX-FUEL & GASOLINE
• FUEL TANK, LINES AND ELECTRIC FUEL SOLENOID VALVES
• DIAGNOSIS AND TESTING
• JACKING & LIFTING
• REMOVAL AND INSTALLATION
• Typical Vent Stack Installation
• FUEL LINE EVACUATION