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Home >> Mazda >> 2005 >> MX-5 Miata Base, Automatic >> Repair and Diagnosis >> Engine Performance >> Fuel Delivery >> Fuel System >> Fuel Line Pressure Inspection

Fuel Line Pressure Inspection

WARNING:
  • Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Always carry out the following procedure with the engine stopped.
  1. Complete the "BEFORE SERVICE PRECAUTION". (See BEFORE SERVICE PRECAUTION (+)
  2. Disconnect the negative battery cable.
  3. Disconnect the fuel pipe on the pulsation damper No.1 outlet side. Set the SST  between the pulsation damper No.1 and the fuel distributor as shown in the figure. (See FUEL INJECTOR REMOVAL/INSTALLATION (+)
    Fig 1: Setting SST Between Pulsation Damper No.1 And Fuel Distributor
    G03637813Courtesy of MAZDA MOTORS CORP.
    NOTE:
    • Verify that a click is heard when the SST is pushed into pulsation damper No.1.
  4. Pull the connector by hand and verify that it is installed securely. Visually inspect that the tabs of the retainer are securely fitted into the connector.
  5. Connect the negative battery cable.
  6. Verify that AT vehicles are in the N range, and MT vehicles are in the neutral position.
  7. Start the engine and idle it. Measure the fuel line pressure.
    • If not as specified, inspect the following:

      Zero or low 

      • FP circuit
      • FP
      • Main fuel line (clogged)
      • Fuel leakage inside pressure regulator

      High 

      • Pressure regulator due to high pressure
      • Return fuel line (clogged)

    Fuel line pressure 

    1. 370-420 kPa {3.7-4.3 kgf/cm2, 53-61 psi} 
  8. Observe the fuel pressure gauge indicator during heavy acceleration.
  9. Verify that the fuel pressure fluctuation is within the specification during the test.
    • If not as specified, inspect the following:
      • PCM
      • FP
      • Fuel line for improper routing, kinks or leakage

    Fuel pressure fluctuation 

    1. 370-420 kPa {3.7-4.3 kgf/cm2, 53-61 psi} 
  10. Turn the ignition switch to the LOCK position.
  11. Measure the fuel hold pressure after 5 min. 
    • If not as specified, inspect the following:
      • FP hold pressure
      • Fuel injector for leakage
      • Fuel line for improper routing, kinks or leakage

    Fuel hold pressure 

    1. More than 250 kPa {2.55 kgf/cm2, 36.3 psi} 
  12. Disconnect the SST  and connect the fuel pipe to the pulsation damper No.1. (See FUEL INJECTOR REMOVAL/INSTALLATION (+)
  13. Complete the "AFTER SERVICE PRECAUTION". (See AFTER SERVICE PRECAUTION (+)
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