GM Cadillac Deville_Fleetwood_ELD_Seville 1990-1998

Fuel Pressure Regulator

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REMOVAL & INSTALLATION





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Fig. View of the fuel pressure regulator (A), vacuum hose (B),and fuel/return lines with quick connect fittings (C)

3.0L Engine

The fuel pressure regulator is a diaphragm operated relief valve having fuel pump pressure on one side and regulator spring pressure and intake manifold vacuum on the other side. The function of the regulator is to maintain a constant 50.0 PSI (350 kPa) fuel pressure across the director spray plate under all operating conditions. The pressure regulator compensates for engine load by increasing fuel pressure as engine intake manifold vacuum drops. The pressure regulator is mounted on the fuel rail.

With the ignition On and engine Off (zero vacuum), system fuel pressure at the pressure test connection should be 46-59 PSI (317-407 kPa) If the pressure regulator supplies fuel pressure which is too low or too high, a driveability condition will result.

  1. The regulator and fuel rail are serviced as an integral unit.
  2.  

4.5L and 4.9L Engines
  1. Disconnect the negative battery cable. Remove the air cleaner upper housing assembly.
  2.  
  3. Relieve the fuel system pressure.
  4.  
  5. Disconnect the fuel return line from rear rail attachment.
  6.  
  7. Remove the pressure regulator-to-rail bracket mounting screws.
  8.  
  9. Remove the pressure regulator and fuel return line as an assembly, from the fuel rail.
  10.  
  11. Disconnect the fuel return line from the pressure regulator. Cover all openings with masking tape to prevent dirt entry.
  12.  

To install:

  1. Prior to assembling the pressure regulator to the fuel return line and rail assembly, lubricate the new O-ring seals with petroleum base grease.
  2.  
  3. Place the O-ring on the fuel return line and assemble the pressure regulator to it.
  4.  
  5. Place a new O-ring seal on the pressure regulator and install the regulator and fuel return line assembly to the fuel rail.
  6.  
  7. Secure the pressure regulator in place with retaining screws. Tighten the retaining screws to 9 ft. lbs. (12 Nm).
  8.  
  9. Connect the fuel return line at the rear of the rail assembly, use a backup wrench on the inlet fitting to prevent turning.
  10.  
  11. Connect the negative battery cable.
  12.  
  13. Turn the ignition switch ON and OFF to allow fuel pressure back into system. Check for leaks.
  14.  
  15. Install the air cleaner assembly. Perform an idle learn procedure.
  16.  

4.6L Engine-Early Model
  1. Remove the fuel pump relay in the engine compartment micro relay center.
  2.  
  3. Relieve the fuel system pressure.
  4.  
  5. Remove the intake manifold top cover.
  6.  
  7. Lift the fuel rail along with the injectors out of the intake manifold housing enough to remove the pressure regulator from the rail.
  8.  
  9. Disconnect the vacuum line from the regulator.
  10.  
  11. Remove the pressure regulator from the fuel rail.
  12.  

To install:

  1. Install the pressure regulator to the fuel rail.
  2.  
  3. Install the fuel rail along with the injectors into the intake manifold housing.
  4.  
  5. Install the intake manifold top cover and tighten to 106 inch lbs. (12 Nm).
  6.  
  7. Install the fuel pump relay in the engine compartment micro relay center.
  8.  
  9. Reconnect the vacuum line from the regulator.
  10.  

4.6L Engine-Late Model

NOTE
Do not use compressed air to test or clean a fuel pressure regulator. Excessive air pressure can damage the fuel pressure regulator. Do not immerse the fuel pressure regulator in a cleaning solvent in order to prevent damage to the regulator.

  1. Remove the Intake Manifold top cover.
  2.  
  3. Relieve fuel system pressure.
  4.  
  5. Disconnect the fuel pressure regulator vacuum hose from the fuel pressure regulator
  6.  
  7. Clean any dirt from the fuel pressure regulator retaining ring.
  8.  
  9. Remove the retaining ring.
  10.  
  11. Catch any spilled fuel using a shop towel.
  12.  
  13. Lift and twist the fuel pressure regulator from the fuel rail socket.
  14.  
  15. Cover the fuel pressure regulator housing to prevent contamination from entering the fuel system.
  16.  
  17. Clean the fuel pressure regulator filter screen with gasoline and a soft brush.
  18.  

To install:


NOTE
When servicing the fuel pressure regulator, insure that the O-ring backup, large O-ring, filter screen, and small O-ring are properly placed on the regulator.

  1. Install new O-rings on the fuel pressure regulator, if a new fuel pressure regulator is not being installed.
    1. Install the regulator seal O-ring (2) (small O-ring).
    2.  
    3. Install the regulator filter (1).
    4.  
    5. Install the regulator seal O-ring (4).
    6.  
    7. Install the O-ring back-up (5).
    8.  

  2.  
  3. Insert the regulator into the fuel rail socket using a turning motion to properly seat the O-rings.
  4.  
  5. Install the retaining ring (3) on the fuel pressure regulator (6).
  6.  
  7. Position the vacuum port on the fuel pressure regulator in the original position.
  8.  
  9. Connect the vacuum hose to the fuel pressure regulator.
  10.  
  11. Connect the negative battery cable.
  12.  
  13. Turn the ignition switch ON for 2 seconds.
  14.  
  15. Turn the ignition switch OFF for 10 seconds.
  16.  
  17. Turn the ignition switch ON .
  18.  
  19. Check for fuel leaks.
  20.  
  21. Install the Intake Manifold top cover.
  22.  

 
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