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High Fuel Pressure Test

  1. Check for engine vacuum leaks. Check for loose or misthreaded fittings, cracks, and blockage which could cause insufficient vacuum supply to fuel pressure regulator. Repair vacuum leaks as necessary. If no vacuum leaks are found, go to next step.
  2. Check fuel pressure regulator housing for damage and dents which could cause a higher spring load on regulator. Check fuel pressure regulator diaphragm operation. See steps 3) and 4) in LOW FUEL PRESSURE TEST. If fuel pressure regulator is okay, go to next step. Replace fuel pressure regulator if defective, and recheck fuel pressure.
  3. Disconnect fuel return line from fuel pressure regulator and fuel tank. Place disconnected hose at fuel tank into an empty container. Using low air pressure (5-10 psi), blow air into disconnected return line at pressure regulator. If fuel return line is restricted, clean or repair return line as necessary and repeat fuel pressure test. If fuel return line is free of restrictions, replace fuel pressure regulator and repeat fuel pressure test. If fuel pressure is still high, go to FUEL INJECTOR TEST.
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