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Home >> Mazda >> 1997 >> B4000 Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Basic Testing >> Fuel System >> Fuel Pressure >> Fuel Pressure Regulator High Pressure
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Fuel Pressure Regulator High Pressure

  1. Install Fuel Pressure Gauge (49 UN01 010) to fuel pressure relief valve (Schrader valve) located on fuel rail. Disconnect fuel return line from fuel rail. Connect a short hose from fuel rail to a one quart container.
  2. Turn ignition on with engine off. Connect New Generation Star (NGS) scan tool to data link connector 2. Connector is located under left side of instrument panel, right of steering column. Using scan tool, select ACTIVATE COMMAND MODES. Select OUTPUT TEST MODE. Press MODE to change to ALL ON mode. Press start to run fuel pump. Measure fuel pressure and ensure fuel is flowing into container.
  3. If fuel pressure remains high, replace fuel pressure regulator. If fuel pressure is okay, check for plugged fuel return line.
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