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Fuel System Test

WARNING: Always relieve residual fuel pressure in fuel delivery system before opening system. To prevent chance of personal injury, cover fittings with shop towel while disconnecting fittings.
  1. Remove cap from pressure test port located in fuel rail. See Fig 1 . Connect Fuel Pressure Gauge (J-34730-1) to pressure fitting.
  2. Start vehicle. Pressure should be approximately 31 psi (2.1 kg/cm2 ) with vacuum hose connected to pressure regulator and 39 psi (2.6 kg/cm2 ) with vacuum hose removed from pressure regulator.
  3. Check fuel pump flow rate. A good fuel pump will deliver at least one liter of fuel per minute with fuel return line pinched off. If fuel pump does not pump adequately, inspect fuel system for a plugged fuel filter or filter sock.
    Fig 1: Fuel System Pressure Test Components
    G12548Courtesy of CHRYSLER MOTORS.
  4. Fuel pump flow rate can be checked by connecting one end of an old A/C gauge hose to fuel test port on fuel rail and inserting other end of hose into a container of at least one liter or more capacity.
  5. Run fuel pump by installing a jumper wire into diagnostic connector terminals D1-5 and D1-6. Be sure to pinch off fuel return line or most of fuel will be returned to fuel tank.