Leak Test
LEAK TESTSpecial Tool(s):
SPECIAL TOOL(S)
Fuel Injection Supply Manifold and Fuel Injectors
1. NOTE: After the vehicle has soaked for several hours, a very slight natural gas smell may emanate from within the intake manifold and intake air system. This is normal, as the fuel injectors leak down from the fuel injection supply manifold to the intake manifold over several hours.
Remove the fuel valve relay from the power distribution box.
2. Construct a jumper wire from 152 mm (6 inches) of 18 gauge wire and two spade terminal ends.
3. Jumper the fuel valve relay circuit from Socket 87 to Socket 30.
4. Remove the jumper wire.
5. Install the fuel valve relay into the power distribution box.
6. Check the spring lock coupling and the fuel injection supply manifold to fuel injector connections for leaks using the Combustible Gas Detector (part of NGV Pressure Test and Venting Kit).
7. If a leak is detected, verify the connection is engaged correctly, then retest.
8. If the leak remains, repair as necessary and retest.
Fuel Tanks, Filter and Lines
1. NOTE: Verify system pressure is at least 10,343 kPa (1,500 psi). If system pressure is below 10,343 kPa (1,500 psi), refuel the vehicle.
Check the fuel tank(s), coalescer/filter and fuel line connections for leaks, using the Combustible Gas Detector.
2. If a leak is detected, verify that the fittings are tightened correctly, then retest.
3. If the leak remains, inspect the O-ring seal, O-ring seal land and sealing surfaces for any damage, distortion or contamination.
4. Repair as necessary and retest.
Rear/Upper Fuel Tank Rack Vapor Vent Box
1. Make the vapor vent box/tool connections.
1 Install the Rotunda Pressure Test Adaptor 134-00122 (part of NGV Pressure and Venting Kit) or equivalent to the upper tank rack flexible vent tube.
2 Install the Rotunda Evaporative Emission Tester 134-00056 or equivalent to the Pressure Test Adaptor.
2. Pressurize the vapor vent box to 5 kPa (17 inches H2O).
3. Monitor the pressure for two minutes. The pressure should not drop more than 1.5 kPa (6 inches H2O).
4. If the pressure drops in excess of 1.5 kPa (6 inches H2O), apply a soapy water solution around the vapor vent box gasket and seals to pinpoint the leak. Install a new gasket or seals as applicable.