High Pressure Regulator (HPR) Replacement

TOOLS REQUIRED
J 41416 Ultrasonic Leak Detector

REMOVAL PROCEDURE

CAUTION:
^ Refer to Compressed Natural Gas (CNG) Flammability Caution in Service Precautions.
^ Refer to Compressed Natural Gas (CNG) Fuel Pressure Relief Caution in Service Precautions.




1. Relieve the CNG fuel system pressure. Refer to the Fuel Pressure Relief Procedure.

CAUTION: Refer to Battery Disconnect Caution in Service Precautions.

2. Disconnect the negative battery cable.
3. Clamp off coolant hoses (1, 7) using coolant hose pinch pliers.
4. Remove hose clamps and hoses from the high pressure regulator coolant fittings (2, 5).




5. Remove the fuel inlet line (1) from the high pressure regulator (2).




6. Remove the fuel outlet line (1) from the high pressure regulator (2).




7. Remove the bolts from the electronic brake control module shield and remove the shield.




8. Loosen but do not remove the lower bracket mounting bolt (4).




9. Remove the high pressure regulator mounting bracket thru-frame (1) nut and bolt (2).




10. Remove the high pressure regulator and bracket assembly (2, 3) from the vehicle (1)




11. Remove the fuel inlet line fitting from the high pressure regulator. Retain the high pressure regulator fuel filter and spring for re-installation if clean.

IMPORTANT: Do not hold the HPR using the hex flange at the end of the HPR near the warning label. Place the HPR in a suitable holding device in order to keep the HPR from spinning in the bracket.

12. Remove the high pressure regulator jam nut (1) and remove the high pressure regulator (3) from the bracket (2).

DISASSEMBLY PROCEDURE

IMPORTANT: Do not hold the HPR using the hex flange at the end of the HPR near the warning label. Place the HPR in a suitable holding device in order to keep the HPR from moving.




1. Remove the coolant hose fittings (2, 5).
2. Remove the pressure relief device (PRD) (4).
3. Remove the fuel outlet fitting (3).

ASSEMBLY PROCEDURE

NOTE: Refer to Fastener Notice in Service Precautions.

IMPORTANT: Apply pipe thread sealant containing Teflon� to the following components prior to installation. Do not use Teflon� tape.




^ Install the fuel outlet fitting (3).

Tighten
Tighten the fitting finger-tight plus 1 to 3 turns.

^ Install the pressure relief device (PRD) (4).

Tighten
Tighten the PRD finger-tight plus 1 to 3 turns.

^ Install the coolant hose fittings.

Tighten
Tighten the coolant hose fittings finger tight plus 1 to 3 turns as required to properly align the fittings.

INSTALLATION PROCEDURE

IMPORTANT: Do not hold the HPR using the hex flange at the end of the HPR near the warning label. Place the HPR in a suitable holding device in order to keep the HPR from spinning in the bracket.

NOTE: Refer to Fastener Notice in Service Precautions.




1. Install the high pressure regulator (3) into the bracket (2) and install the high pressure regulator jam nut (1).

Tighten
Tighten the jam nut to 54 N.m (40 lb ft).

CAUTION: Refer to Compressed Natural Gas (CNG) O-Ring Caution in Service Precautions.

IMPORTANT: Ensure that a clean or new fuel filter (3) and the spring (4) and gasket (2) are installed prior to installation of the fuel inlet fitting (6).




2. Install the fuel inlet fitting (6) using new O-rings. Lubricate the O-rings with petroleum jelly or equivalent.

Tighten
Tighten the fuel inlet fitting to 37 N.m (27 lb ft).




3. Place the high pressure regulator and bracket assembly (2, 3) onto the loosely installed lower mounting bracket bolt (4).




4. Install the thru-frame mounting bracket nut, washer and bolt (2).

Tighten
Tighten the thru-frame nut to 37 N.m (27 lb ft).




5. Tighten the lower bracket mounting bolt (4).

Tighten
Tighten the mounting bolt to 28 N.m (21 lb ft).




6. Install the electronic brake control module shield and bolts.

Tighten
Tighten the shield mounting bolts to 28 N.m (21 lb ft).




7. Connect the fuel outlet line (1) to the outlet line fitting using a new O-ring. Lubricate the O-ring with petroleum jelly or equivalent.

Tighten
Tighten the fuel outlet line fitting finger-tight plus 1 to 3 turns.




8. Install the fuel inlet line (1) to the fuel inlet fitting.

Tighten
Tighten the fuel inlet line fitting to 37 N.m (27 lb ft).




9. Install the coolant hoses (1, 7) and clamps to the high pressure regulator coolant fittings (2, 6).
10. Remove the coolant hose pinch pliers.
11. Connect the negative battery cable.
12. Prime the CNG fuel system by cycling the ignition ON and OFF several times.
13. Start the engine and use the J 41416 in order to inspect for CNG fuel system leaks at each serviced fitting.
14. Inspect for proper coolant level and fill as necessary.