EVAP System Pressure Test
- Ensure fuel tank contains at least 2 gallons of fuel unless there has never been fuel in the system. Ensure fuel filler cap is properly installed. Disconnect line from fuel vapor separator, at EVAP canister. See Fig 1. Using a "T" fitting and adapter, connect nitrogen cylinder and regulator, and a water manometer (0-30" H2O or more) to end of line from fuel vapor separator, at EVAP canister.
- Pressurize EVAP system to 26.5-27.5" of H2O, allow to stabilize, and turn off nitrogen supply. Monitor water manometer for changes in EVAP system pressure. If system pressure decreases more than 2.5" of H2O in 2.5 minutes, go to next step. EVAP system is okay if pressure decreases within specification or increases slightly.
- Maintain EVAP system pressure at 26.5-27.5" of H2O. Using soapy water, locate EVAP system leak. See Fig 1. Repair as necessary and repeat pressure test.
Courtesy of LAND ROVER NORTH AMERICA, INC.