2001 GMC Savana 1500 Fuel Pressure Regulator

You should vent the CNG fuel system in a well-ventilated work area, keep sparks, flames, and smoking material away from the area, and wear the appropriate hearing protection during the venting procedure.

You need to disconnect the negative battery cable, loosen the fuel filler cap to relieve the tank vapor pressure, remove the engine cover, connect a J 34730-1A, or the equivalent, to the fuel pressure connection, wrap a shop towel around the fitting while connecting the gauge to avoid spillage, install the bleed hose into an approved container and open the valve to bleed the system pressure and drain any fuel remaining in the gauge into an approved container.

You should tighten any loosened fittings to the correct torque, open the manual lock-down screws located on the HPL manual shut-off fittings, and leave the manual lock-down screws closed on any vehicle that will require CNG fuel TANK venting.

The coolant temperature is greater than 30°C (86°F). the FTP sensor indicates the CNG fuel level is OK. the engine speed is greater than 1,300 RPM. the TP sensor continuously indicates the throttle is less than 6 percent for at least 800ms, and the VSS indicates vehicle speed is greater than 56 km/h (35 mph).

You need to turn the ignition off, remove the CNG 20-amp fuse to prevent a CNG prime pulse from occurring during service, and slowly open the fittings to release any remaining pressure when disconnecting a fuel line.