Equipment Affected Technical Bulletin LPG Lock-Off valve replacement procedures for 4.2 Liter Ford V6 Ford 4.2L V-6 powered tractors with LPG fuel systems. Part Description Discrepancy Fuel Pressure Lock-off Valve High failure rate of the low-pressure lock-off valve. Possible Failure Fuel valve sticking closed, causing engine shutdown due to fuel starvation. Correction Procedure Replace the low-pressure lock-off with the new high-pressure lock-off Preparation 1. Before lifting the tractor, a. Turn off the LP tank. b. Run the engine until it shuts down to use up any fuel in the fuel lines. c. Disconnect the negative cable from the battery. 2. Jack up the tractor and install safety jack stands. 3. Unbolt the access cover and remove it from the fuel system box. 4. Remove the LPG feed hose from the top of the regulator 5. Loosen both hose clamps holding the 1 inch LPG hose running between the regulator and the Mega Jector Page 1 of 8
6. Verify that the regulator (red arrow) is set up as shown in the picture below. If the regulator is not installed as in the photo below, then remove the regulator from the box and set up per photo in Step 6A. 6A. Use this configuration to ensure proper fit. Note the bracket, regulator, and fittings positions. 8 8 7. Twist the 1 inch LPG hose to loosen the connection. 8. Loosen the two bolts that mount the regulator to the bracket. It might be necessary to loosen the bottom bracket mounting bolts to gain access to the regulator mounting bolts. Page 2 of 8
9 15 10 9. Cut the two wires going to the Low Pressure Lock-Off about 4 inches from the valve. 10. Loosen the hose clamps on the output side of the Lock-Off valve. 11. Use a 1 1/16 wrench and turn the Lock-Off to loosen. 12. Once the lock-off is loose, you can remove the two bolts that mount the bracket to the box. 13. Turn the Low Pressure lock-off until it is loose from the regulator. 14. Remove the hose and the low Pressure lock-off from the box. Remove the barbed fitting from the hose end of the lock-off. Keep the hose clamps and discard the rest. 15. If the bushing in the 90º elbow did not come off with the lock-off, it will also need to be removed. 16. Install the new pipe adapter bushing that was supplied in the kit and the 1-inch barb fitting that was removed from the Low Pressure lock-off. Be sure to use thread tape or sealant to prevent possible leakage. Page 3 of 8
Note that the new adapter bushing supplied in the kit is indexed with the flat side against the bracket Brass barbed fitting that was removed from the old Low Pressure Lock-off valve 17. Install the 8-inch long fuel hose and clamps onto the barbed fitting on the Mega Jector. Then connect the barbed fitting on the regulator to the hose. 18. Tighten the two bolts that mount the regulator to the bracket. 19. Install the two bolts that hold the regulator mounting bracket to the box and tighten. 20. Tighten the hose two hose clamps on the hose between the regulator and the Mega Jector Page 4 of 8
21. Remove the 45º and straight 5/8 SAE fittings from the top of the regulator. You will be re-using these fittings in the new High Pressure lock-off valve 21 22. If the new High Pressure Lock-off (a) does not have a case ground wire (b) as in photo below, cut the ground wire and splice an additional 6-inch (300MM) wire to the ground wire as shown below. a Before 22 b 23. Connect the added wire to wire 17 in the harness. After Page 5 of 8
Pressure port 24 24. Install the male-to-male pipe adapter and the lock-off onto the top of the regulator. Also, note the indexing when tightened. 25. Seal the threads of the 45º fitting with Teflon tape or silicone sealant. 26. Install the 45º fitting into the new High Pressure lock-off without the straight 5/8 SAE fitting. Note the indexing in the photo. This can be adjusted once everything has been assembled. 26 Page 6 of 8
Technical Bulletin 27. Install the straight 5/8 SAE fitting into the 45º fitting. Use thread tape or sealant on threads. 27 28. Note the indexing of the components. In some cases it may be necessary to turn the 90º fitting as indicated in the photo below. Note the indexing Page 7 of 8
Technical Bulletin 29. Connect the LPG line to the regulator. It may be necessary to temporarily remove the clamps holding the LPG hose to the frame rail to allow for enough length to fit properly and have a gradual bend to the regulator connection. Re-attach the clamps used to secure the LPG hose. 30. Remove the two-wire harness that was attached to the Low Pressure lock-off. This will disconnect on the engine at the right rear of the valve cover. After removing the harness, cut to the correct length leaving plenty of slack for movement and securing. 31. Locate on the two-wire harness which wire is in position B Verify that the connection on the engine has a red wire in position B. This will be the power wire going to the lock-off. Crimp on the appropriate electrical connector for the power wire. 32. Position A on the two-wire harness is the ground wire. Check to make sure that a Green wire is in that position on the engine connector. Crimp on the appropriate electrical connector for this wire. 33. Put the poly loom on this harness and connect the terminals together at the High Pressure lock-off. Route the harness appropriately and re-connect to the engine harness. 34. Re-assemble all remaining parts, including the access panel on the box. Check over all work before turning on the gas. 35. Turn on the gas and check for leaks. After verifying that everything is sealed and there are no leaks, Re-connect the Negative Battery terminal. 36. Start the engine to and re-check work. 37. If you have any problems or questions, please contact the Harlan at (913)342-5650 Page 8 of 8