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Home >> Honda >> 2003 >> Civic Si >> Repair and Diagnosis >> Engine Performance >> System >> EVAP System (Hatchback) >> Fuel Tank Vapor Control Valve Test >> Valve Test
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Valve Test

  1. Make sure the fuel tank is less than half full.
  2. Remove the fuel fill cap.
  3. Disconnect the fuel tank vapor signal tube (A).
    Fig 1: Disconnecting The Fuel Tank Vapor Signal Tube
    G01399665Courtesy of AMERICAN HONDA MOTOR CO., INC.
  4. Disconnect the vacuum hoses (A) from the EVAP canister (B), then plug the ports with plugs (C).
    Fig 2: Disconnecting The Vacuum Hoses From The EVAP Canister
    G01399666Courtesy of AMERICAN HONDA MOTOR CO., INC.
  5. Disconnect the vacuum hose (D) from the EVAP canister vent shut valve (E), and connect a vacuum pump/gauge, 0-30 in Hg. (A973X-041-XXXXX or equivalent) to the vacuum hose.
  6. Pump the vacuum pump 80 times.
    • If the vacuum holds, go to step 7.
    • If the vacuum does not hold, go to step  10.
  7. Connect a second vacuum pump to the fuel tank vapor signal tube (A).
    Fig 3: Connecting A Second Vacuum Pump To The Fuel Tank Vapor Signal Tube
    G01399667Courtesy of AMERICAN HONDA MOTOR CO., INC.
  8. Apply vacuum (1 pump) to the fuel tank vapor signal tube (A), then check the vacuum on the pump in step 6.
  9. Fill the fuel tank with fuel, then check for fuel in the EVAP two way valve (A), and fuel tank vapor recirculation hose (B).
    NOTE: At either location, tiny droplets of fuel are normal.
    • If fuel runs out of the hoses at either location, replace the fuel tank vapor control valve.
    • If the fuel does not run out of the hoses, the fuel tank vapor system function is normal.
    Fig 4: Checking For Fuel In The EVAP Two Way Valve
    G01399668Courtesy of AMERICAN HONDA MOTOR CO., INC.
    Fig 5: Checking For Fuel In Fuel Tank Vapor Recirculation Hose
    G01399669Courtesy of AMERICAN HONDA MOTOR CO., INC.
  10. Disconnect the fuel tank vapor quick disconnect from the EVAP canister, then plug the port on the canister. Reapply vacuum (80 pumps).
    • If the vacuum holds, replace the fuel tank control valve (see FUEL TANK VAPOR CONTROL VALVE REPLACEMENT ).
    • If the vacuum does not hold, inspect the EVAP canister vent shut valve O-ring. If the O-ring is OK, replace the EVAP canister, and repeat step 4.
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