Engine Controls - Removal & Installation - Bi-Fuel & Cng Chevrolet Chevy Express H2500

COMPUTERIZED ENGINE CONTROLS

Note. The fuel control system on these engines is separate from the gasoline fuel system and has unique parts. This article only covers removal and installation procedures for CNG components on bi-fuel vehicles. Procedures for systems and components that are the same as gasoline powered models are not included in this article. See REMOVAL & INSTALLATION - CHEVY EXPRESS & SAVANA - GASOLINE article.

Note. Numbers in parenthesis refer to numbers in illustration.

1. Disconnect the negative battery cable. Remove the fender brace mounting bolts (1). (Scheme 117) Remove the fender brace.
2. Remove the FICM hold-down screws (2) from the mounting bracket. Remove the connector position assurance lock and disconnect the electrical connector (3) from the FICM. Remove the FICM mounting bracket bolts (4). Remove the FICM mounting bracket nut (5) from the horn mounting stud. Remove the FICM mounting bracket from the vehicle.
3. To install, reverse removal procedure. Tighten all fasteners to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__torque-specifications).

Scheme 117

All vehicles are equipped with a Powertrain Control Module (PCM) for gasoline operation and an Fuel Injection Control Module (FICM) for CNG operation. For PCM information, see POWERTRAIN CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in CHEVY EXPRESS & SAVANA - GASOLINE article.

PROGRAMMING

Note. Programming is not required for the Fuel Injection Control Module. For all gasoline related programming, see PROGRAMMING in SELF-DIAGNOSTICS - 4.8L, 5.3L & 6.0L EXPRESS & SAVANA - GASOLINE article.

FUEL RAIL PRESSURE SENSOR

Note. Before removal, clean the fuel rail with a spray type engine cleaner, GM X-30A or equivalent. Follow the package instructions. DO NOT soak fuel rails in liquid cleaning solvent.

Note. Numbers in parenthesis refer to numbers in illustration.

1. Release fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-system-pressure-release). Disconnect the negative battery cable.
2. Remove the engine cover. See «ENGINE COVER»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__engine-cover) under MISCELLANEOUS. Disconnect the Fuel Rail Pressure (FRP) sensor electrical connectors (4). (Scheme 118) Remove the FRP sensor (13) and discard the "O" ring. (Scheme 119)
3. Install the Fuel Rail Pressure (FRP) sensor using a NEW "O" ring. Tighten the FRP sensor to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__torque-specifications).
4. To complete installation, reverse removal procedure. Start the vehicle and inspect for CNG fuel leaks at the serviced fittings with the J 45878 or an equivalent leak detector.

Scheme 118

Scheme 119

FUEL RAIL TEMPERATURE SENSOR

Note. Before removal, clean the fuel rail with a spray type engine cleaner, GM X-30A or equivalent. Follow the package instructions. DO NOT soak fuel rails in liquid cleaning solvent.

Note. Numbers in parenthesis refer to numbers in illustration.

1. Release fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-system-pressure-release) under FUEL SYSTEMS. Disconnect the negative battery cable. Remove the engine cover.
2. Disconnect the Fuel Rail Temperature (FRT) sensor electrical connectors (3). (Scheme 118) Remove the FRT sensor (11) and discard the "O" ring. (Scheme 119)
3. Install the fuel rail temperature (FRT) sensor (2) using a NEW "O" ring. Tighten the FRT sensor to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__torque-specifications).
4. To complete installation, reverse removal procedure. Start the vehicle and inspect for CNG fuel leaks at the serviced fittings with the J 45878 or an equivalent leak detector.

FUEL TANK PRESSURE SENSOR

Note. Numbers in parenthesis refer to numbers in illustration.

1. Release fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-system-pressure-release) under FUEL SYSTEMS. Disconnect the negative battery cable.
2. Remove the CNG fuel tank shield. See «FUEL TANK SHIELD»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng) under FUEL SYSTEMS. Disconnect the Fuel Tank Pressure (FTP) sensor (1) electrical connector. Remove the FTP sensor from the tank valve. (Scheme 120) Discard the "O" ring.
3. Install the FTP sensor in the tank valve using a NEW "O" ring. Tighten the FTP sensor to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__torque-specifications).
4. Connect the FTP sensor electrical connector. Connect the negative battery cable. Start the vehicle and use Ultrasonic Leak Detector (J 45878) in order to inspect for CNG fuel leaks at each serviced fitting. Install the CNG fuel tank shield. See «FUEL TANK SHIELD»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng).

Scheme 120

HIGH PRESSURE LOCK-OFF SOLENOID

1. Remove the fuel tank shield. See «FUEL TANK SHIELD»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng) under FUEL SYSTEMS. Release fuel system pressure. See «FUEL SYSTEM PRESSURE RELEASE»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-system-pressure-release) under FUEL SYSTEMS.
2. Disconnect the negative battery cable. Disconnect the vent hose from the High Pressure Lock-Off (HPL) Solenoid. Remove the manual vent tool and all fittings.
3. Remove the fuel tank from the vehicle. See «FUEL TANKS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-tanks) under FUEL SYSTEMS. Vent the CNG fuel pressure from the tank. See «FUEL TANK VENTING PROCEDURE»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-tank-venting-procedure) under FUEL SYSTEM PRESSURE RELEASE under FUEL SYSTEMS.
4. Disconnect the vent hose from the HPL. Remove the manual vent tool and all fittings. Remove the fuel inlet fitting from the HPL solenoid and discard the "O" rings. Remove the fuel outlet fitting from the HPL solenoid and discard the "O" rings. Using HPL Crowfoot (J 43602), loosen the HPL solenoid.
5. Unthread the HPL solenoid from the CNG fuel tank and discard the "O" ring. Inspect the inside of the CNG fuel tank for water, rust, or other contaminants. If necessary, clean the CNG fuel tank. See «FUEL TANK CLEANING»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-tank-cleaning) under FUEL SYSTEMS.

1. Install a NEW "O" ring on the HPL solenoid. Lubricate "O" ring with petroleum jelly or equivalent before installation. Install the HPL solenoid in the tank and tighten hand-tight. Install the tank into the vehicle ensuring that the HPL solenoid will be properly oriented for reconnection of the fuel lines. Install the tank using the OLD mounting strap nuts and bolts. DO NOT install the fuel line fittings.
2. Tighten the HPL solenoid. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__torque-specifications) . See «TORQUE ADAPTOR COMPENSATION»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__torque-adaptor-compensation) under TORQUE SPECIFICATIONS. Remove the OLD mounting strap nuts and bolts and discard them. Ensure that the tank is properly oriented for fuel line connection.
3. Install NEW mounting strap bolts and nuts. Tighten the mounting strap nuts. Complete the fuel tank installation by connecting the fuel lines, electrical connectors and fuel tank pressure sensor. See «FUEL TANKS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-tanks) under FUEL SYSTEMS.
4. Fuel the vehicle and check for CNG fuel leaks in 3 stages at the following pressures: 500 psi 1,500 psi and 3,000 psi. Using Ultrasonic Leak Detector (J 45878), inspect for fuel leaks at the HPL solenoid at each pressure. Connect the negative battery cable. Start and operate the engine on CNG. Inspect for fuel leaks at each serviced fitting using ultrasonic leak detector. Attach the information label supplied with the replacement HPL solenoid in a visible location on the head of the tank. Install the tank shield. See «FUEL TANK SHIELD»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng) under FUEL SYSTEMS.

LOW PRESSURE LOCK-OFF SOLENOID

Note. Numbers in parenthesis refer to numbers in illustrations.

1. Relieve the fuel system pressure. See «FUEL SYSTEM PRESSURE RELEASE»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-system-pressure-release) under FUEL SYSTEMS. Disconnect the negative battery cable. Remove the engine cover. See «ENGINE COVER»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__engine-cover) under MISCELLANEOUS.
2. Disconnect the Low Pressure Lock-off (LPL) solenoid electrical connector. Remove the LPL solenoid coil retaining nut (1). (Scheme 121) Remove the LPL solenoid coil (2). Remove the LPL solenoid core tube (3).
3. Disconnect the fuel inlet line (8) and discard the copper sealing washer. (Scheme 118) Disconnect the fuel crossover line (7) and discard the copper sealing washer.
4. Remove the LPL solenoid housing mounting screws (1). (Scheme 119) Remove the LPL solenoid housing from the fuel rail (5) and discard the "O" ring (12).

Scheme 121

Note. Use NEW "O" rings upon installation. Lubricate all "O" rings with petroleum jelly or equivalent before installation.

1. Install the Low Pressure Lock-Off (LPL) solenoid housing to the fuel rail using a NEW "O" ring. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__torque-specifications) .
2. Connect the CNG fuel inlet line using a NEW copper sealing washer. Tighten the fuel line fitting to specification.
3. Connect the CNG fuel crossover line using a NEW copper sealing washer. Tighten the fuel line fitting to specification.
4. Ensure the LPL piston assembly spring is installed inside the core tube.
5. Install the core tube and piston assembly into the LPL solenoid housing. Tighten the core tube to specification.
6. Install the LPL solenoid coil onto the core tube. Install the LPL solenoid coil retaining nut. Tighten the nut to specification.
7. Connect the LPL solenoid electrical connector. Install the negative battery cable. Start the vehicle and inspect for CNG fuel leaks at the serviced fittings with the Gas Detector (J 45878) or equivalent combustible gas detector. Install the engine cover.

COOLING SYSTEM BLEEDING

Place a large funnel in radiator filler neck. Pour one-half of cooling system capacity of DEX-COOL® coolant into radiator. Fill remaining capacity with clean, drinkable water to 0.5" (13 mm) below radiator filler neck. Start engine and let cooling system warm up. If coolant level drops when thermostat opens, add clean drinkable water to just below filler neck. Install radiator cap and top off reservoir. Check for leaks.

FUEL SYSTEM PRECAUTIONS

When venting the Compressed Natural Gas (CNG) system, take the following precautions in order to prevent fire and personal injury

1. Use the proper grounding procedure to an earth ground in order to prevent a build-up of static electricity which can lead to an electrical discharge.
2. Use the Tank Vent Kit with a vent stack.
3. Vent the CNG fuel tank in a well ventilated work area.
4. Keep sparks, flames, and smoking material away from the area.
5. Wear the appropriate hearing protection during the venting procedure. A sudden pressure loss from an uncontrolled gas leak can cause hearing damage.

Tank Inspection

Inspect the CNG fuel tank and brackets every three years or 36,000 mi (60,000 km), whichever comes first. Record the inspection information in the CNG Fuel Tank Inspection Record, located in the owner's manual supplement. DO NOT remove the tank from the vehicle for general inspections. However, if the tank has been exposed to corrosive chemicals such as acid or alkali, remove the tank in order to perform a complete inspection. Replace tanks with dents to the metal edges greater than 0.060" (1.52 mm) deep. Replace tanks with sharp gouges penetrating the paint and the metal.

A multi-coat paint system with a zinc-rich primer protects the metal tank. Inspect and recoat chips as necessary. See TANK REPAIR .

If the tank is replaced, perform the following steps: Obtain a new CNG Fuel Only label. Obtain a new Bi-fuel Information label. Record the new tank service expiration date, the date of the manufacture plus 15 years, on both labels.

Tank Repair

The following two repair methods are recommended depending on whether the zinc-rich primer is still intact

1. Level 1 chips do not expose the gray zinc-rich primer. Level 1 chips do not require resurfacing. Recoat the chip using any commercial room temperature cure two-component epoxy resin, Loctite® Part No. 14600 or equivalent, if the chip has not penetrated the zinc-rich primer.
2. Level 2 chips are chips or abrasions that penetrate the zinc-rich primer and exposed the bare metal. Recoat Level 2 chips or abrasions in order to prevent corrosion. Sand the damaged area in order to remove any rust and to rough-up the surrounding coating. Clean the damaged area with a commercial prepaint cleaning solvent Dupont® Prep Sol or equivalent. Apply a zinc-rich cold galvanizing primer LPS® Part No. 00516 or equivalent. Coat the area after the primer has cured using a room temperature cure two-component epoxy resin-Loctite® Part No. 14600 or equivalent.

Tank Label Inspection

Verify that the CNG fuel tank label is in place. Contact the GM Technical Assistance Center if the label is not readable, peeling or missing. Verify that the tank expiration date on the tank and the underhood label matches. If needed, replace the underhood label so the expiration date matches the tank label.

Mounting Bracket Inspection

Verify that the rubber isolator is properly seated on the tank brackets and straps. Inspect the rubber isolator for cracks, deterioration or other damage. Replace the rubber isolator if necessary. Inspect the tank brackets, straps, mounting frame and mounting hardware for cracks, corrosion, deformation or other damage. Replace if necessary.

Removing Tank From Service

CNG fuel tanks have a fifteen year service life from the date of manufacture. The CNG tank manufacture date appears on a label on the tank. The tank expiration date is on the CNG Fuel Only label and the Bi-fuel Information label. Any tank in service for fifteen years or more must be removed from service using the following procedure.

Remove the tank. See FUEL TANKS . Vent the tank. See FUEL TANK VENTING PROCEDURE under FUEL SYSTEM PRESSURE RELEASE. Disconnect the vent hose. Place the tank outside in a well ventilated area. Allow the tank to stand for 24 hours with either the tank valve energized or the manual valve opening tool installed. Drill a 0.25" (0.64 cm) hole after the last digit of the tank identification number stamped into the valve end of the tank. Dispose of the tank in a safe and approved manner.

FUEL SYSTEM PRESSURE RELEASE

Preliminary Check

Perform fuel pressure relief procedure only after approved diagnostic procedures have isolated a CNG system component replacement or CNG system components require removal for other vehicle repairs. This vehicle is designed to start and operate on CNG.

Fuel Pressure Relief Procedure

Note. With a scan tool, communicate with the PCM. If communication cannot be established and the Diagnostic System Check - Alternative Fuels (Engine Controls) has already been performed, proceed to step 5 .

1. Store the DTC Information with a scan tool. Clear the DTC Information with a scan tool. Turn OFF the ignition.
2. Start and idle the engine. Ensure that the engine is operating on CNG by observing the following: The Fuel Indicator Lamp (FIL) is off (KL6) The AFO Enable scan tool display indicates the engine is operating on alternative fuel.
3. With a scan tool, select the high pressure lock-off (HPL) solenoid special function. While the engine is operating on CNG command the HPL solenoid OFF and observe the fuel tank pressure sensor data parameter. The fuel tank pressure should slowly decrease. If the fuel pressure fails to decrease proceed to step 10 .
4. When the engine stalls or a switch-over to gasoline is observed, perform the following: Turn OFF the ignition. Remove the Alt. Fuels 20-amp fuse in order to disable the CNG fuel system. A small amount of CNG will remain in the fuel lines and components. Slowly open the fittings in order to release any remaining pressure when disconnecting a fuel line. Fuel Pressure Relief for the CNG system is now complete. Proceed to step 10 .
5. Close the manual lock-down screw located on the end of each High Pressure Lock-Off (HPL) solenoid. The manual shut-off fitting is closed by rotating the Allen screw clockwise until fully seated. Turn OFF the ignition. Disconnect the negative battery cable.
6. Vent the CNG fuel system in a well ventilated work area. Keep sparks, flames, and smoking material away from the area. Wear the appropriate hearing protection during the venting procedure. A sudden pressure loss from an uncontrolled gas leak can cause hearing damage. Slowly loosen the fuel line fitting at the tee for several turns.
7. Fuel Pressure Relief for the CNG system is complete when the fuel line can be pulled away from the "O" ring face seal and fuel does not vent.
8. Replace the "O" ring face seals at all fittings that were disconnected or loosened. After all necessary repairs are complete perform the following: Tighten any loosened fittings to the correct torque. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__torque-specifications) . Leave the manual lock-down screws closed on any vehicle that will require CNG fuel tank venting.
9. Open the manual lock-down screws located on the HPL manual shut-off fittings by rotating the Allen screw counter-clockwise until fully seated on any vehicle that does not require venting of the CNG fuel tanks. If the service necessary for the vehicle requires that the ignition be turned ON with CNG components or lines disconnected, keep the Alt. Fuels 20 amp fuse removed in order to prevent CNG fuel venting during an ignition ON prime pulse.
10. If the service necessary for the vehicle requires the CNG fuel tanks to be relieved of all internal pressure, see «FUEL TANK VENTING PROCEDURE»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-tank-venting-procedure) .

Fuel Tank Venting Procedure

Venting cannot be stopped once the High Pressure Lock-Off (HPL) solenoid has been opened using the manual vent tool. Venting the CNG fuel tank will damage the HPL solenoid. Venting is only necessary for high pressure lock-off replacement, internal tank cleaning, tank replacement or tank shipping.

1. Remove the CNG fuel tank shield. See «FUEL TANK SHIELD»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng) . Relieve the fuel system pressure. See «FUEL PRESSURE RELIEF PROCEDURE»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-pressure-relief-procedure) . Disconnect the negative battery cable. Disconnect the fuel outlet line from the tank. Install a cap supplied from the CNG Tank Vent Kit (J 42435) onto the fuel line fitting of the fuel outlet port. Tighten the cap.
2. If the front tank is being vented, remove the Fuel Tank Pressure (FTP) sensor and install a fitting supplied from the CNG tank vent kit into the FTP sensor port. The rear tank is already capped at this port. On either tank, disconnect the fuel inlet line from the tank. Connect the female end of the vent hose to the fuel line fitting.
3. Connect the male end of the vent hose to a vent stack. Refer to the tank vent kit container for instructions on how to properly construct a vent stack. Connect the ground strap to the FTP sensor port fitting and to the vent stack earth ground.
4. Remove the manual shut-off fitting from the HPL solenoid. Obtain the manual vent tool supplied from the tank vent kit. Rotate the screw on the manual vent tool counter-clockwise in order to fully retract the plunger. Install the manual vent tool into the HPL solenoid port with the plunger fully retracted. Tighten the manual vent tool. Slowly turn the manual vent tool screw clockwise until the plunger is fully extended.
5. Open the tank vent kit in-line valve if equipped. The tank should always contain some pressure and begin to vent. Allow the CNG fuel tank to vent until the pressure gauge reads 0 psi (0 kPa). If the tank stops venting and pressure is indicated on the tank vent kit gauge, inspect the vent line for a frozen fitting. The fitting will eventually thaw and fuel will again continue to vent.
6. When the tank is completely vented, remove the vent line from the fuel fitting. Remove the fitting and cap from the FTP sensor port. Remove the fuel fitting from the fuel outlet port. Remove the manual vent tool. If the tank is to be re-used, replace the high pressure lock-off. See «HIGH PRESSURE LOCK-OFF SOLENOID»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__high-pressure-lock-off-solenoid) . If both tanks require venting, repeat procedure on the other tank.

1. Release fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-system-pressure-release) . Disconnect the negative battery cable. Remove the fuel tank shield. See «FUEL TANK SHIELD»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng) . Remove the check valve clamp bolt. Remove the fill line at the high pressure lock-off fitting. Disconnect the fill line at the fill valve fitting. Remove the fill line assembly from the vehicle.
2. To install, place the fill line assembly between the rear tank high pressure lock-off and the fill valve. Install the fill line fitting to the fill valve using a NEW "O" ring. Lubricate "O" ring with petroleum jelly or equivalent before installation. Tighten the fill line fitting. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__torque-specifications) . Install the fill line at rear tank high pressure lock-off fitting using a new "O" ring. Install the check valve clamp bolt. Tighten the bolt. Tighten the fill line fitting. Connect the negative battery cable. Prime the CNG fuel system by cycling the ignition ON and OFF several times. Start the engine and use Ultrasonic Leak Detector (J 41416) in order to inspect for CNG fuel system leaks at each serviced fitting. Install the fuel tank shield. See «FUEL TANK SHIELD»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng) .

1. Remove the Fill Line assembly from the vehicle. See «FILL LINE»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng) . Mark the orientation of the inlet and outlet lines on the check valve. Remove the inlet line from the check valve. Remove the outlet line from the check valve.
2. To install, connect the outlet line to the check valve using new "O" rings. Lubricate the "O" rings with petroleum jelly or equivalent. Tighten the fuel line. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__torque-specifications) . Connect the inlet line to the check valve using new "O" rings. Lubricate the "O" rings with petroleum jelly or equivalent. Align the inlet and outlet lines to the same orientation as previously recorded. Tighten the fuel line. Install the Fill Line assembly into the vehicle.

Removal & Installation (Bi-Fuel)

Note. Numbers in parenthesis refer to numbers in illustrations.

1. Relieve the bi-fuel system pressure. See «FUEL SYSTEM PRESSURE RELEASE»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-system-pressure-release) under FUEL SYSTEMS. Disconnect the negative battery cable.
2. Remove the screws (1) that retain the fuel filler door and remove the fuel filler door. (Scheme 122) Remove the fill line fitting (1) from the fill valve. (Scheme 123) Remove the fill valve cover from the mounting plate. Remove the fill valve jam nut (2).
3. Remove the fill valve from the mounting plate (2). (Scheme 122)
4. Install the fill line fitting to the fill valve using a NEW "O" ring. Tighten the fill line fitting. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__torque-specifications). To complete installation, reverse removal procedure. Prime the CNG fuel system by cycling the ignition ON and OFF several times. Start the engine and use Ultrasonic Leak Detector (J 45878) in order to inspect for bi-fuel system leaks at each serviced fitting.

Scheme 122

Scheme 123

Removal & Installation (CNG)

Note. Numbers in parenthesis refer to numbers in illustrations.

1. Relieve the CNG fuel system pressure. Release fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-system-pressure-release) under FUEL SYSTEMS. Disconnect the negative battery cable.
2. Remove the screws (1) and spacers (2) that retain the fuel filler door to the body. (Scheme 124)
3. Remove the fill line fitting (1) from the fill valve. (Scheme 123)
4. Remove the fill valve jam nut (3). Remove the fill valve (4) from the mounting plate (5). (Scheme 124)
5. Install the fill line fitting to the fill valve using a NEW "O" ring. Tighten the fill line fitting. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__torque-specifications). To complete installation, reverse removal procedure. Prime the CNG fuel system by cycling the ignition ON and OFF several times. Start the engine and use Ultrasonic Leak Detector (J 45878) in order to inspect for bi-fuel system leaks at each serviced fitting.

Scheme 124

Remove the "O" ring. Remove the circlip. Remove the fill valve filter. Clean the filter in solvent. Blow dry the filter using compressed air. Be sure that the filter passages are clear. Replace the filter if needed. Install the fill valve filter. Install the circlip. Install the "O" ring.

FUEL HOSES/PIPES

Removal & Installation (Rear High Pressure Lock-Off (HPL) Solenoid-To-Front High Pressure Lock-Off (HPL) Solenoid)

1. Release fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-system-pressure-release) .
2. Disconnect the negative battery cable. Remove the fuel tank shield. See «FUEL TANK SHIELD»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng) . Disconnect the fuel line at the rear tank high pressure lock-off fitting. Disconnect the fuel line at the front tank high pressure lock-off fitting and remove the fuel line from the vehicle.
3. Connect the fuel line to the front tank high pressure lock-off fitting using NEW "O" rings. Lubricate "O" ring with petroleum jelly or equivalent before installation. Tighten the fuel line fitting. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__torque-specifications) . Connect the fuel line to the rear tank high pressure lock-off fitting using new "O" rings.
4. Tighten the fuel line fitting. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__torque-specifications) . Connect the negative battery cable. Prime the CNG fuel system by cycling the ignition ON and OFF several times. Start the engine and use Ultrasonic Leak Detector (J 45878) in order to inspect for CNG fuel system leaks at each serviced fitting. Install the fuel tank shield. See «FUEL TANK SHIELD»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng) .

Removal & Installation (Front High Pressure Lock-Off (HPL) Solenoid-To-High Pressure Regulator (HPR) Union

1. Release fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-system-pressure-release) . Disconnect the negative battery cable. Remove the fuel tank shield. See «FUEL TANK SHIELD»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng) . Disconnect the fuel line fitting at the line union. Disconnect the fuel line from the front tank high pressure lock-off fitting. Remove the fuel line assembly from the vehicle.
2. Install the fuel line assembly between the front tank and the fuel line union. Lubricate "O" ring with petroleum jelly or equivalent before installation. Connect the fuel line to the front tank high pressure lock-off fitting using new "O" rings. Tighten the fuel line fitting. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__torque-specifications) . Connect the negative battery cable.
3. Prime the CNG fuel system by cycling the ignition ON and OFF several times. Start the engine and use Ultrasonic Leak Detector (J 41416) in order to inspect for CNG fuel system leaks at each serviced fitting. Install the fuel tank shield. See «FUEL TANK SHIELD»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng) .

Removal & Installation (High Pressure Regulator (HPR) Union-To-High Pressure Regulator (HPR) Hose)

1. Release fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-system-pressure-release) . Disconnect the negative battery cable. Remove the fuel tank shield. See «FUEL TANK SHIELD»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng) . Disconnect the fuel line fitting at the line union.
2. Remove the fuel line clamp bolt. Remove the clips that hold the fuel line to the brake line. Observe where the clips connect to the brake line for reinstallation. Disconnect the fuel line from the high pressure regulator. Remove the fuel line assembly from the vehicle.
3. To install, route the fuel line assembly along the frame between the line union fitting and the high pressure regulator. Lubricate the "O" rings with petroleum jelly or equivalent before installation. Connect the fuel line to the high pressure regulator using new "O" rings.
4. Tighten the fuel line. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__torque-specifications) . Install the fuel line clamp bolt. Install the clips that hold the fuel line to the brake line at the locations previously observed. Connect the negative battery cable. Prime the CNG fuel system by cycling the ignition ON and OFF several times. Start the engine and use Ultrasonic Leak Detector (J 41416) in order to inspect for CNG fuel system leaks at each serviced fitting. Install the fuel tank shield. See «FUEL TANK SHIELD»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng) .

Removal & Installation (High Pressure Regulator (HPR)-To-Low Pressure Lock-Off (LPL) Union)

1. Release fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-system-pressure-release) . Disconnect the negative battery cable. Remove the engine cover. See «ENGINE COVER»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__engine-cover) under MISCELLANEOUS. Remove the fuel line at the low pressure lock-off solenoid fitting. Remove the fuel line from the high pressure regulator. Remove the fuel line retainer located along the transmission bellhousing from the CNG fuel line and the gasoline fuel line. Remove the fuel line assembly from the vehicle.
2. To install, route the fuel line between the low pressure lock-off solenoid and the high pressure regulator. Lubricate the "O" rings with petroleum jelly or equivalent before installation. Connect the fuel line at the low pressure lock-off solenoid fitting using new "O" rings. Tighten the fuel line. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__torque-specifications) .
3. Install the fuel line retainer between the CNG fuel line and the lower gasoline fuel line. Connect the negative battery cable. Prime the CNG fuel system by cycling the ignition ON and OFF several times. Start the engine and use Ultrasonic Leak Detector (J 41416) in order to inspect for CNG fuel system leaks at each serviced fitting. Install the engine cover.

FUEL RAIL & FUEL INJECTORS

Note. Before removal, clean the fuel rail assemblies with a spray type engine cleaner, GM X-30A or equivalent, if necessary. Follow the package instructions. DO NOT soak fuel rails in liquid cleaning solvent.

Note. Remove the fuel rail assembly carefully in order to prevent damage to the injector electrical connector terminals and the injector spray tips.

Note. Numbers in parenthesis refer to numbers in illustration.

Removal (Bi-Fuel)

1. Relieve the CNG fuel system pressure before servicing. See «FUEL SYSTEM PRESSURE RELEASE»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-system-pressure-release). Relieve gasoline fuel system pressure. See «FUEL SYSTEM PRESSURE RELEASE»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-gasoline__fuel-system-pressure-release) under FUEL SYSTEMS in CHEVY EXPRESS & SAVANA - GASOLINE article.
2. Disconnect the negative battery cable. Remove the engine cover. See «ENGINE COVER»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__engine-cover) under MISCELLANEOUS.
3. Disconnect the CNG fuel lines (7, 8 and 10) from the fuel rails. (Scheme 118) Disconnect the fuel rail temperature and pressure sensor electrical connectors (3 and 4). Disconnect the low pressure lock-off solenoid connector. Disconnect the eight CNG fuel injector electrical connectors (2 and 12).
4. Disconnect the accelerator control cable and the cruise control cable from the cable bracket. Disconnect the cruise control cable engine-end fitting from the stud on the throttle lever, if equipped. Disconnect the accelerator control cable and the cruise control cable from the throttle body.
5. Remove the upper engine wire harness retainer nut. (Scheme 125) Disconnect the evaporative emission (EVAP) purge valve harness connector. Reposition the upper engine wire harness aside. Mark the electrical connectors to their corresponding gasoline injectors to ensure correct sequential injector firing order after reassembly.
6. Pull the Connector Position Assurance (CPA) of the injector connector up. Pull the tab (1) on the injector connector in. (Scheme 126) While pushing the tab on the injector connector in, release the CPA (2). Disconnect the fuel injector electrical connector. Repeat for each injector connector.
7. Disconnect the fuel feed and return pipes (1 and 2) from the fuel rail. (Scheme 127) Disconnect the fuel pressure regulator vacuum line. Loosen the crossover tube to right fuel rail retainer screw. Remove the right fuel rail attaching nuts. Remove the left fuel rail attaching nuts.
8. Cap the fittings and plug the holes when servicing the fuel system in order to prevent dirt and other contaminants from entering open pipes and passages. Remove the gasoline and CNG fuel rails as an assembly.
9. Remove the crossover tube rail retainer screws. Remove the crossover tube. Remove the injector (7) retainer bolt and clip (10). (Scheme 119) Remove the injector from the fuel rail with a pulling a twisting motion. Remove the fuel injector adaptor (9) from the fuel injector. Repeat for the remaining fuel injectors.
10. Remove the fuel rail pressure sensor (13) and discard the "O" ring. See «FUEL RAIL PRESSURE SENSOR»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-rail-pressure-sensor) under SENSORS & SWITCHES.
11. Remove the fuel rail temperature sensor (11) and discard the "O" ring. See «FUEL RAIL TEMPERATURE SENSOR»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-rail-temperature-sensor) under SENSORS & SWITCHES. If necessary, remove the low pressure lock-off solenoid (2) mounting screws (1) and discard the "O" ring (12).

Scheme 125

Scheme 126

Scheme 127

Note. Use NEW "O" rings upon installation. Lubricate all "O" rings with petroleum jelly or equivalent before installation.

1. To install reverse removal procedure. Tighten all fasteners to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__torque-specifications). Lubricate the NEW fuel injector lower "O" ring seals with clean engine oil. Install the NEW "O" ring seals to the end of each injector. (Scheme 128)
2. Apply a 0.020" (5 mm) band of Threadlock (GM P/N 1234382), or equivalent, to the threads of all of the fuel rail attaching studs.
3. Connect the CNG fuel inlet line using a NEW copper sealing washer. Connect the CNG fuel crossover line using NEW copper sealing washers.
4. Start the vehicle and inspect for CNG fuel leaks at the serviced fittings with the Ultrasonic Leak Detector (J 45878) or an equivalent leak detector. With a scan tool command a switch-over to gasoline and inspect for gasoline fuel leaks. Install the engine cover.

Scheme 128

Note. Before removal, clean the fuel rail assemblies with a spray type engine cleaner, GM X-30A or equivalent, if necessary. Follow the package instructions. DO NOT soak fuel rails in liquid cleaning solvent.

Note. Remove the fuel rail assembly carefully in order to prevent damage to the injector electrical connector terminals and the injector spray tips.

Note. Use NEW "O" rings upon installation. Lubricate all "O" rings with petroleum jelly or equivalent before installation.

Note. Numbers in parenthesis refer to numbers in illustration.

1. Relieve the CNG fuel system pressure. See «FUEL SYSTEM PRESSURE RELEASE»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-system-pressure-release). Disconnect the negative battery cable. Remove the engine cover.
2. Disconnect the CNG fuel lines (7, 8 and 10) from the fuel rails. (Scheme 118) Disconnect the fuel rail temperature and pressure sensor electrical connectors (3 and 4). Disconnect the low pressure lock-off solenoid connector. Disconnect the eight CNG fuel injector electrical connectors (2 and 12).
3. Disconnect the accelerator control cable and the cruise control cable from the cable bracket. Disconnect the cruise control cable engine-end fitting from the stud on the throttle lever, if equipped. Disconnect the accelerator control cable and the cruise control cable from the throttle body.
4. Remove the upper engine wire harness retainer nut. (Scheme 125) Set the upper engine wire harness aside. Remove the right fuel rail attaching bolts.
5. Support the fuel rail after the fuel rail is removed in order to avoid damaging the fuel rail components. Cap the fittings and plug the holes when servicing the fuel system in order to prevent dirt and other contaminants from entering open pipes and passages. Remove the left fuel rail attaching bolts. Remove the CNG fuel rail.
6. Remove the injector (7) retainer bolt and clip (10). (Scheme 119) Remove the injector from the fuel rail with a pulling a twisting motion. Repeat steps for the remaining fuel injectors. Remove the fuel rail pressure sensor (13) and discard the O-ring. See «FUEL RAIL PRESSURE SENSOR»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-rail-pressure-sensor) under SENSORS & SWITCHES.
7. Remove the fuel rail temperature sensor (11) and discard the "O" ring. See «FUEL RAIL TEMPERATURE SENSOR»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-rail-temperature-sensor) under SENSORS & SWITCHES. Remove the low pressure lock-off solenoid (2) mounting screws (1) and discard the O-ring (12).
8. To install reverse removal procedure. Tighten all fasteners to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__torque-specifications). Lubricate the NEW fuel injector lower "O" ring seals with clean engine oil. Install the NEW "O" ring seals to the end of each injector.
9. Apply a 0.020" (5 mm) band of (GM P/N 1234382) threadlock, or equivalent, to the threads of all of the fuel rail attaching studs.
10. Connect the CNG fuel inlet line using a NEW copper sealing washer. Connect the CNG fuel crossover line using NEW copper sealing washers.
11. Start the vehicle and inspect for CNG fuel leaks at the serviced fittings with the Ultrasonic Leak Detector (J 45878) or an equivalent leak detector. With a scan tool command a switch-over to gasoline and inspect for gasoline fuel leaks. Install the engine cover.

FUEL TANKS

Removal & Installation (Front Fuel Tank)

Note. Numbers in parenthesis refer to numbers in illustration.

1. Release fuel system pressure. See «FUEL SYSTEM PRESSURE RELEASE»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-system-pressure-release).
2. Disconnect the negative battery cable. Remove the fuel tank shield. See «FUEL TANK SHIELD»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng). Vent the CNG fuel from the CNG fuel tank if necessary. See «FUEL TANK VENTING PROCEDURE»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-tank-venting-procedure) under FUEL SYSTEM PRESSURE RELEASE.
3. Raise and support vehicle. Disconnect the electrical connectors (1) at the high pressure lock-off solenoid as necessary. (Scheme 129) Disconnect the fuel outlet line (2) from the High Pressure Lock-Off (HPL) solenoid. Disconnect the fuel inlet line at the high pressure lock-off solenoid fitting. Mark the tanks as front and rear prior to removal from the vehicle.
4. Place CNG Tank Lifting Fixture (J 45397-2) using a suitable lifting device such as a transmission lift jack beneath the tank to be removed ensuring placement is between the tank straps. Remove and discard the retaining bolts (1). (Scheme 130) Remove the tank strap upper mounting pins. Remove the tank straps from the vehicle (2). Lower the fuel tank from the vehicle. Remove the tank (3) from the lift jack using CNG Tank Lifting Bar (J 45529) and a suitable lifting device.
5. To install, position the tank onto the lift jack using CNG tank lifting bar and a suitable lifting device. Raise the fuel tank into the tank mounting frame, ensuring that the high pressure lock-off solenoid is properly oriented to the fuel lines. Place the straps into the tank mounting bracket. Install the tank strap upper mounting pins. Install the new tank strap mounting nuts and bolts. Tighten the tank strap mounting bolts. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__torque-specifications).
6. Connect the fuel inlet line at the front tank high pressure lock-off solenoid fitting using NEW "O" rings. Lubricate the "O" rings with petroleum jelly or equivalent before installation. Connect the fuel outlet line to the high pressure lock-off using NEW "O" rings. Tighten fittings. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__torque-specifications). Connect the electrical connectors at the high pressure lock-off solenoid as necessary. Connect the negative battery cable. Prime the CNG fuel system by cycling the ignition ON and OFF several times. Start the engine and use Ultrasonic Leak Detector (J 45878) in order to inspect for CNG fuel system leaks at each serviced fitting.

Scheme 129

Scheme 130

Removal (Rear Fuel Tank)

1. Release fuel system pressure. See «FUEL SYSTEM PRESSURE RELEASE»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-system-pressure-release). Disconnect the negative battery cable. Remove the fuel tank shield. See «FUEL TANK SHIELD»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng). Vent the CNG fuel from the CNG fuel tank if necessary. See «FUEL TANK VENTING PROCEDURE»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-tank-venting-procedure) under FUEL SYSTEM PRESSURE RELEASE. Disconnect the electrical connectors at the high pressure lock-off solenoid as necessary. Disconnect the fuel outlet line from the High Pressure Lock-Off (HPL) solenoid fitting. Disconnect the fuel inlet line at the check valve fitting.
2. Mark the tanks as front and rear prior to removal from the vehicle. Place CNG Tank Lifting Fixture (J 45397) using a suitable lifting device such as a transmission lift jack beneath the tank to be removed ensuring placement is between the tank straps. Remove and discard the retaining nuts and bolts. (Scheme 131)or (Scheme 132). Remove the tank strap upper mounting pins. Remove the tank straps from the vehicle. Lower the fuel tank from the vehicle. Remove the tank from the lift jack using CNG Tank Lifting Bar (J 45529) and a suitable lifting device.

Scheme 131

Scheme 132

1. Position the tank onto the lift jack using CNG tank lifting bar and a suitable lifting device. Raise the fuel tank into the tank mounting frame ensuring that the high pressure lock-off solenoid is properly oriented to the fuel lines. Place the straps into the tank mounting bracket. Install the tank strap upper mounting pins. Install the new tank strap mounting nuts and bolts. Tighten the tank strap mounting bolts. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__torque-specifications) .
2. Lubricate the "O" rings with petroleum jelly or equivalent before installation. Connect the fuel inlet line at the check valve fitting using NEW "O" rings. Connect the fuel outlet line to the high pressure lock-off fitting using NEW "O" rings. Tighten the fittings. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__torque-specifications) . Connect the electrical connectors at the high pressure lock-off solenoid as necessary. Connect the negative battery cable. Fill the CNG fuel system. Start the engine and use Ultrasonic Leak Detector (J 41416) in order to inspect for CNG fuel system leaks at each serviced fitting.

FUEL TANK CLEANING

Note. Tank cleaning is only necessary when a part such as the high pressure lock-off solenoid has failed due to fuel contamination or when excess water accumulation, that may reduce fuel capacity, is suspected within the tank.

1. Perform the fuel pressure relief procedure. See «FUEL SYSTEM PRESSURE RELEASE»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-system-pressure-release) . Perform the fuel tank venting procedure. See «FUEL TANK VENTING PROCEDURE»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-tank-venting-procedure) under FUEL SYSTEM PRESSURE RELEASE. Perform the High Pressure Lock-Off (HPL) solenoid removal procedure leaving the HPL solenoid installed into the tank finger-tight. See «HIGH PRESSURE LOCK-OFF SOLENOID»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__high-pressure-lock-off-solenoid) . Place the CNG Tank Support Harness (J 44244) on the shop floor. Lower the CNG fuel tank on top of the CNG tank support harness. Place the CNG tank support harness support flap so that the HPL solenoid protrudes through the flap.
2. Place the CNG tank support harness straps around the CNG fuel tank placing the end strap over the HPL solenoid and around the neck of the CNG fuel tank. Securely fasten the CNG tank support harness straps around the CNG fuel tank. Longer CNG fuel tanks will require the use of all the CNG tank support harness straps. Connect the CNG tank support harness to a suitable lifting device. Slowly raise the CNG fuel tank until the HPL solenoid is several inches above the ground ensuring that the HPL solenoid does not contact the floor during the lifting process.
3. Place a container underneath the HPL solenoid in order to collect any drained fluids. Remove the HPL solenoid, allowing any fluids to drain completely from the CNG fuel tank. Dispose of any collected fluids in a safe and approved manner. Flush the inside of the CNG fuel tank using clean water. Dry the inside of the CNG fuel tank using compressed air. Install the HPL solenoid finger-tight. Slowly lower the CNG fuel tank back to the ground ensuring the HPL solenoid does not contact the ground. Remove the CNG tank support harness from the CNG fuel tank. Complete the installation of the HPL solenoid into the tank and the tank into the vehicle by completing the installation steps as indicated in the HPL solenoid replacement procedure. See «HIGH PRESSURE LOCK-OFF SOLENOID»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__high-pressure-lock-off-solenoid) .

Remove the tank shield bolts while an assistant holds the shield in place. (Scheme 133) Lower the shield from the vehicle. To install, position the shield around the tank frame. While an assistant holds the shield in place, loosely install the eight retaining bolts. Tighten the bolts. See TORQUE SPECIFICATIONS.

Scheme 133

See FUEL TANK PRESSURE SENSOR under SENSORS & SWITCHES.

Note. Numbers in parenthesis refer to numbers in illustration.

1. Release fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-system-pressure-release). Disconnect the negative battery cable. Clamp off coolant hoses using coolant hose pinch pliers. Remove hose clamps and hoses from the high pressure regulator coolant fittings.
2. Remove the fuel inlet lines (1 and 2) from the high pressure regulator (3) and discard the "O" rings. (Scheme 134)or (Scheme 135). Remove the fuel outlet line (4) from the filter and discard the copper sealing washer.
3. On cutaway model, remove mounting bracket bolts and nuts (1 and 2) and remove the high pressure regulator assembly (3). (Scheme 136) On passenger/cargo model, remove the mounting bracket bolts (1) and high pressure regulator assembly (2). (Scheme 137)
4. Install the fuel inlet fitting using a NEW "O" ring. Lubricate the "O" rings with petroleum jelly or equivalent before installation. Tighten to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__torque-specifications).
5. Connect the fuel outlet line to the filter using a NEW copper sealing washer. Tighten the fuel outlet line fitting to specification.
6. Remove the coolant hose pinch pliers. Connect the negative battery cable. Prime the CNG fuel system by cycling the ignition on and off several times. Start the engine and use Ultrasonic Leak Detector (J 45878) in order to inspect for CNG fuel system leaks at each serviced fitting.

Scheme 134

Scheme 135

Scheme 136

Scheme 137

Note. Numbers in parenthesis refer to numbers in illustration.

1. Release fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__fuel-system-pressure-release). Disconnect the negative battery cable. If necessary, remove high pressure regulator. See «HIGH PRESSURE REGULATOR»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng) removal and installation procedure.
2. Remove the fuel line (1) fuel inlet line fitting (2). (Scheme 138) Remove the fuel inlet line fitting from the high pressure regulator (3). Remove the fuel filter spring, seal and fuel filter (4).
3. Install the spring, filter and seal. Install the fuel inlet fitting using NEW "O" rings. Lubricate the "O" rings with petroleum jelly or equivalent before installation. Tighten the fuel inlet fitting. See «TORQUE SPECIFICATIONS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-bi-fuel-cng__torque-specifications).
4. Connect the fuel inlet line to the inlet line fitting. Lubricate the "O" rings with petroleum jelly or equivalent. Tighten the fuel inlet line fitting to specification. Connect the negative battery cable. Prime the CNG fuel system by cycling the ignition ON and OFF several times. Start the engine and use Ultrasonic Leak Detector (J 45878) in order to inspect for CNG fuel system leaks at each serviced fitting.

Scheme 138

IGNITION SYSTEMS

Note. Ignition system on bi-fuel vehicles is the same as gasoline vehicles. See IGNITION SYSTEMS in CHEVY EXPRESS & SAVANA - GASOLINE article.

EMISSION SYSTEMS & SUB-SYSTEMS

Note. Evaporative system on bi-fuel vehicles is the same as gasoline vehicles. See EMISSION SYSTEMS & SUB-SYSTEMS in CHEVY EXPRESS & SAVANA - GASOLINE article.

ENGINE COVER

Remove instrument panel lower extension. Release the engine cover retaining straps. Remove the engine cover from the vehicle. To install, ensure that the engine cover sealing strip is properly seated between the engine cover and the vehicle. Install the engine cover to the vehicle. Install the engine cover retaining straps. Install the instrument panel lower extension.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

TORQUE ADAPTOR COMPENSATION

Note. Ensure that HPL Crowfoot (J 43602) removal tool is straight (0 degrees) on the torque wrench.

You must compensate for the torque wrench and the HPL crowfoot. Refer to the formula for compensation of the torque wrench. To obtain your dial reading perform the following procedure: Multiply your torque wrench length in inches by 225 ft. lbs. (305 Nm). Example for an 18" torque wrench: 18 X 225 = 4050. Add 3 to the length of your torque wrench. 18 + 3 = 21. Divide the first value obtained by the second value obtained. The result indicates the amount of torque your wrench should tighten the HPL solenoid to. 4050 divided by 21 = 192.8. For an 18" long torque wrench, tighten the HPL solenoid to 192.8 ft. lbs. (261.4 Nm).

See also:
• REMOVAL & INSTALLATION - CHEVY EXPRESS & SAVANA - GASOLINE
• POWERTRAIN CONTROL MODULE
• PROGRAMMING
• FUEL SYSTEM PRESSURE RELEASE
• TORQUE SPECIFICATIONS
• FUEL SYSTEM PRESSURE RELEASE
• ENGINE COVER
• FUEL TANK SHIELD
• FUEL TANKS
• FUEL TANK VENTING PROCEDURE
• FUEL TANK CLEANING
• TORQUE ADAPTOR COMPENSATION
• TANK REPAIR
• FUEL PRESSURE RELIEF PROCEDURE
• HIGH PRESSURE LOCK-OFF SOLENOID
• FUEL RAIL PRESSURE SENSOR
• FUEL RAIL TEMPERATURE SENSOR
• FUEL TANK PRESSURE SENSOR