2003 Infiniti Q45FACTORY OEM SERVICE PROCEDURE

Fuel Pressure Check

WARNING: This page is about a different car, the 2004 Infiniti Q45. However, it is still accessible from the selected car via links, so may be relevant.

Before disconnecting fuel line, release fuel pressure from fuel line to eliminate danger.Β 

NOTE:
  • Use Fuel Pressure Gauge Kit (J-44321) to check fuel pressure.
  • Prepare pans or saucers under the disconnected fuel line because the fuel may spill out. The fuel pressure cannot be completely released because F50 models do not have fuel return system.
  1. Release fuel pressure to zero. Refer to FUEL PRESSURE RELEASEΒ .
  2. Install the inline fuel quick disconnected fitting between fuel damper and injector tube.
    Fig 1: Locating Fuel Damper
    G00744992Courtesy of NISSAN MOTOR CO., U.S.A.
  3. Connect the fuel pressure test gauge (quick connector adapter hose) to the inline fuel quick disconnected fitting.
  4. Turn ignition switch ON and check for fuel leakage.
  5. Start engine and check for fuel leakage.
  6. Read the indication of fuel pressure gauge.
    1. At idling: Approximately 350 kPa (3.57 kg/cmΒ 2 , 51 psi)Β 
  7. If result is unsatisfactory, go to next step.
  8. Check the following.
    • Fuel hoses and fuel tubes for clogging
    • Fuel filter for clogging
    • Fuel pump
    • Fuel pressure regulator for clogging

      If OK, replace fuel pressure regulator.

      If NG, repair or replace.

Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.

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