2007 Lexus LS 460LFACTORY OEM SERVICE PROCEDURE

Fuel Pressure Check: Overview

WARNING: This page is about a different car, the 2004 Nissan Maxima. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION:
  • Be careful not to scratch or get the fuel hose connection area dirty when servicing, so that the quick connector o-ring maintains sealability.
  • Use Fuel Pressure Gauge Kit J-44321 and Fuel Pressure Adapter J-44321-6 to check fuel pressure.
  • Do not perform fuel pressure check with electrical system operating (i.e. lights, rear defog, A/C, etc.). Fuel pressure gauge may indicate false readings due to varying engine loads and changes in manifold vacuum.
  1. Release fuel pressure to zero. Refer to "FUEL PRESSURE RELEASE ".
  2. Remove fuel hose using Quick Connector Release J-45488. Refer to INTAKE MANIFOLD .
    • Do not twist or kink fuel hose because it is plastic hose.
    • Do not remove fuel hose from quick connector.
    • Keep fuel hose connections clean.
  3. Install Fuel Pressure Adapter J-44321-6 and Fuel Pressure Gauge (from kit J-44321) as shown in Fig 1.
    • Do not distort or bend fuel rail tube when installing fuel pressure gauge adapter.
    • When reconnecting fuel hose, check the original fuel hose for damage and abnormality.
    Fig 1: Install Fuel Pressure Adapter J-44321-6 and Fuel Pressure Gauge (From Kit J-44321)
    G00875288Courtesy of NISSAN MOTOR CO., U.S.A.
  4. Turn ignition switch ON (reactivate fuel pump), and check for fuel leakage.
  5. Start engine and check for fuel leakage.
  6. Read the indication of fuel pressure gauge.
    • During fuel pressure check, check for fuel leakage from fuel connection every 3 minutes.
      1. At idling: Approximately 350 kPa (3.57 kg/cm 2 ,51 psi) 
  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
    1. If OK, replace fuel pressure regulator.
    2. If NG, repair or replace.
  9. Before disconnecting Fuel Pressure Gauge and Fuel Pressure Adapter J-44321-6, release fuel pressure to zero. Refer to "FUEL PRESSURE RELEASE ".
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:

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

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