Computers and Control Systems: Service and Repair

Fuel Shut-off Valves (CNG):

FUEL LINE PRESSURE RELEASE PROCEDURE.
1. Close the fuel control valves on all four cylinders by turning the valves completely clockwise.
2. Ensure the manual shut-off valve is in the open position. The valve is open when the handle is parallel with the fuel lines.
3. Start or attempt to start the engine. If the engine runs, let it run until it runs out of fuel. Attempt to start the engine by cranking for 6 seconds.
4. Pausing 10 seconds between attempts, repeat step 3 two more times.
5. If the check valve or fuel fill receptacle is to be serviced, slowly loosen the inlet side of the fuel fill tube fitting at the check valve until fuel has purged.

WARNING: The fuel cylinders still contain high-pressure fuel.

FUEL CYLINDER PRESSURE RELEASE PROCEDURE.
1. Close the fuel control valves on the cylinders not being serviced by turning the valves completely clockwise.
2. Ensure the manual shut-off valve is in the open position. The valve is open when the handle is parallel with the fuel lines.
3. Start the engine and let it run until the fuel is depleted.
4. Attempt to start the engine by cranking for 6 seconds.
5. Pausing 10 seconds between attempts, repeat steps 3 and 4 two more times.


WARNING: The fuel cylinders that are not being serviced still contain high-pressure fuel.