Fuel Tank Inspection

NOTE:

The rollover valve and the fuel shut-off valve or check valve (two-way) built into the fuel tank and fuel tank leakage are inspected in this inspection.

Complete the "BEFORE SERVICE PRECAUTION". (See BEFORE SERVICE PRECAUTION ).
Remove the battery cover. (See BATTERY REMOVAL/INSTALLATION [LF, L5] ).
Disconnect the negative battery cable. (See BATTERY REMOVAL/INSTALLATION [LF, L5] ).
Remove the fuel tank and the fuel pump unit as a single unit. (See FUEL TANK REMOVAL/INSTALLATION ).
Perform the following procedure to verify the fuel tank airtightness.
1. Plug the fuel pump unit pipe, ports B and C.
  Fuel filter (high-pressure) is a built-in type in fuel pump unit
  
  Fig 1: Identifying Fuel Pump Unit And Ports - Fuel Filter (High-Pressure) Built-In Type In Fuel Pump Unit
  Courtesy of MAZDA MOTORS CORP.
  
  Fuel filter (high-pressure) is not a built-in type in fuel pump unit
2. Apply a pressure of 3 kPa {23 mmHg, 0.9 inHg} to port A and wait for a while.
3. Verify that there is no air flow leakage from the fuel tank.
  - If there is air flow, replace the fuel tank. (See FUEL TANK REMOVAL/INSTALLATION ).
Plug the fuel pump unit pipe and port B.

Fig 2: Identifying Fuel Pump Unit And Ports - Fuel Filter (High-Pressure) Not Built-In Type In Fuel Pump Unit
Courtesy of MAZDA MOTORS CORP.

Fuel filter (high-pressure) is a built-in type in fuel pump unit

Fig 3: Identifying Fuel Pump Unit And Ports - Fuel Filter (High-Pressure) Built-In Type In Fuel Pump Unit
Courtesy of MAZDA MOTORS CORP.

Fuel filter (high-pressure) is not a built-in type in fuel pump unit
Level the fuel tank.
Apply a pressure of 3 kPa {23 mmHg, 0.9 inHg} to port A and wait for a while.
With the pressure still applied, verify that there is air flow port C and the pressure is 0-3 kPa {0-23 mmHg, 0-0.9 inHg}.
- If there is no air flow, replace the fuel tank. (See FUEL TANK REMOVAL/INSTALLATION ).
Apply a pressure of -0.5 kPa {-3.8 mmHg, -0.1 inHg} to port A and wait for a while.
With the pressure still applied, verify that there is air flow port C and the pressure is -0.5-0 kPa {-3.8-0 mmHg, -0.1-0 inHg}.

Fig 4: Identifying Fuel Pump Unit And Ports - Fuel Filter (High-Pressure) Not Built-In Type In Fuel Pump Unit
Courtesy of MAZDA MOTORS CORP.
- If there is no air flow, replace the fuel tank. (See FUEL TANK REMOVAL/INSTALLATION ).
- If there is air flow, place the fuel tank upside down.
Apply a pressure to port A and wait for a while.
Fuel filter (high-pressure) is a built-in type in fuel pump unit

Fig 5: Identifying Fuel Pump Unit And Ports - Fuel Filter (High-Pressure) Built-In Type In Fuel Pump Unit
Courtesy of MAZDA MOTORS CORP.

Fuel filter (high-pressure) is not a built-in type in fuel pump unit
With the pressure still applied, verify that there is no air flow from port C.
- If there is air flow, replace the fuel tank. (See FUEL TANK REMOVAL/INSTALLATION ).
  
  Fig 6: Identifying Fuel Pump Unit And Ports - Fuel Filter (High-Pressure) Not Built-In Type In Fuel Pump Unit
  Courtesy of MAZDA MOTORS CORP.