High Pressure Lock-Off (HPL) Solenoid Replacement
TOOLS REQUIRED^ J 41416 Ultrasonic Leak Detector
^ J 43602 HPL Crowfoot Removal Procedure
CAUTION: Do not install this part if you can not completely refill the vehicle with CNG after a repair. Failure to properly leak-check the system after the part replacement may result in serious injury, death, or damage to the vehicle or the part.
1. Remove the fuel tank shield.
2. Relieve the CNG fuel system pressure. Refer to Fuel Pressure Relief Procedure.
3. Vent the CNG fuel pressure from the tank. Refer to Fuel Tank Venting Procedure.
CAUTION: Refer to Battery Disconnect Caution in Service Precautions.
4. Disconnect the negative battery cable.
5. Disconnect the vent hose (1) from the HPL.
6. Remove the manual vent tool and all fittings.
7. Remove the fuel inlet fitting from the HPL and discard the O-rings.
8. Remove the fuel outlet fitting from the HPL and discard the O-rings.
9. Using the J 43602 HPL crowfoot removal tool, loosen the HPL.
10. Remove the CNG fuel tank from the vehicle. Refer to Fuel Tank Replacement (Front) or Fuel Tank Replacement (Rear).
11. Unthread the HPL from the CNG fuel tank and discard the O-ring.
12. Inspect the inside of the CNG fuel tank for water, rust, or other contaminants.
13. If necessary, clean the CNG fuel tank. Refer to Fuel Tank Cleaning.
INSTALLATION PROCEDURE
1. Install a NEW O-ring on the HPL.
2. Lubricate the O-ring with petroleum jelly.
3. Install the HPL in the tank and tighten hand-tight.
4. Install the tank into the vehicle ensuring that the HPL 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.
NOTE: Refer to Fastener Notice in Service Precautions.
5. Tighten the HPL as specified below.
Tighten
Tighten the HPL to a nominal torque of 305 N.m (225 lb ft) at 0 degrees. You must compensate for the torque wrench and the HPL crowfoot. Refer to the formula below for compensation of the torque wrench.
IMPORTANT: Ensure that the J 43602 HPL crowfoot removal tool is straight (0 degrees) on the torque wrench.
6. To obtain your dial reading perform the following procedure:
^ Multiply your torque wrench length in inches by 305 (225).
18 inch torque wrench example:
18 X 305 = 5,490.
^ Add 3 to the length of your torque wrench.
18 inch torque wrench example: 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 to.
18 inch torque wrench example: 5,490 divided by 21 =261.4.
For an 18 inch long torque wrench tighten the HPL to 261.4 N.m.
7. Remove the OLD mounting strap nuts and bolts (4, 5) and discard them.
The rear tank is shown. The front tank is similar.
8. Ensure that the tank is properly oriented for fuel line connection.
9. Install NEW mounting strap bolts and nuts.
Tighten
Tighten the mounting strap nuts to 47 N.m (35 lb ft).
10. Complete the fuel tank installation by connecting the fuel lines, electrical connectors and fuel tank pressure sensor. Refer to Fuel Tank Replacement (Front) or Fuel Tank Replacement (Rear).
CAUTION: The high pressure lock-off solenoid seal is more likely to leak at a lower fuel pressure. Always perform the fuel leak procedure exactly as specified. Failure to follow the proper procedures may result In serious injury or damage to the vehicle or part.
11. Fuel the vehicle and check for CNG fuel leaks in 3 stages at the following pressures:
11.1. 500 psi
11.2. 1,500 psi
11.3. 3,000 psi
12. Using the J 41416, inspect for fuel leaks at the HPL at EACH pressure.
CAUTION: Refer to Battery Disconnect Caution in Service Precautions.
13. Connect the negative battery cable.
14. Start and operate the engine on CNG.
15. Inspect for fuel leaks at each serviced fitting using the J 41416.
16. Attach the information label supplied with the replacement HPL in a visible location on the head of the tank.
17. Install the tank shield.