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Fuel System Pressure Test

  1. Relieve fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE under FUEL PRESSURE  . Connect a 0-100 psi (0-7.0 kg/cm2 ) fuel pressure gauge to the pressure test port fitting on fuel rail.
  2. Remove vacuum line from fuel pressure regulator. Start vehicle and note gauge reading. Reconnect vacuum line and note gauge reading. See FUEL SYSTEM PRESSURE SPECIFICATIONS table. Ensure pressure readings are as specified. If fuel pressure is not higher with vacuum line disconnected, inspect pressure regulator vacuum line for cause of no vacuum.
  3. If fuel pressure is high, inspect fuel return line for kinks and blockage. If fuel pressure is low, momentarily pinch off fuel return line. If pressure remains low, inspect fuel supply line, fuel filter and fuel rail inlet for blockage. If pressure rises, replace fuel pressure regulator.
FUEL SYSTEM PRESSURE SPECIFICATIONS

Application psi (kg/cm2 )
Vacuum Line Disconnected 39-41 (2.70-2.88)
Vacuum Line Connected 31 (2.18)
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