ParkAvenue 1997-1999

Fuel Rail (Supply Manifold) & Injectors

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Removal & Installation



Specific to:

Buick LeSabre 1986-1999

Buick Park Avenue 1996-1999

Oldsmobile 88 1992-1999

Oldsmobile Delta 88 1986-1988

Oldsmobile LSS 1996-1999

Pontiac Bonneville 1987-1999

The fuel injector is serviced as a complete assembly only. If you find that the fuel injectors are leaking, the engine oil may be contaminated with fuel and require changing.

  1. Properly relieve the fuel system pressure.
  2.  
  3. Remove the fuel injector sight shield and/or the air cleaner assembly as necessary.
  4.  
  5. If not already done, disconnect the negative battery cable.
  6.  
  7. Remove the fuel rail from the vehicle, as outlined later in this section.
  8.  
  9. Remove the fuel injector retaining clip(s), then separate the injector from the fuel rail. Discard the injector retaining clips and replace with new ones during installation.
  10.  



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Fig. After removing the fuel rail, remove the injector retaining clip ...



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Fig. ... then remove the injector from the fuel rail

  1. Remove and discard the fuel injector upper and lower O-rings, and the lower O-ring back-up.
  2.  



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Fig. Remove and discard the O-ring from the top of the injector



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Fig. There is an O-ring and O-ring back-up on the bottom of the injector. Remove and discard the O-ring ...



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Fig. ... then remove and discard the O-ring back-up. All O-rings should be replaced before installation

Different injectors are calibrated for different flow rates. When ordering new injectors, be sure to order the identical part number that is inscribed on the old injector.



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Fig. Fuel injector (3), retaining clip (2), upper O-ring (1), lower O-ring (5) and O-ring back-up (4)

To install:


CAUTION
To reduce the risk of fire and personal injury, always install the injector O-rings in the proper position. If the upper and lower O-rings are different colors (black and brown, for example), be sure to install the black O-ring in the upper position and the brown O-ring in the lower position. The O-rings are of the same size, but are made of different materials.

The fuel injector lower O-ring uses a nylon collar, called the O-ring back-up, to properly position the O-ring on the injector. Be sure to install the O-ring back-up, or the sealing O-ring may move on the injector when installing the fuel rail. This can result in a vacuum leak and driveability problems will occur.

  1. Lubricate the new O-ring seals with clean engine oil and install them on the injector.
  2.  
  3. Assemble a new retainer clip onto the injector.
  4.  
  5. Install the fuel injector into the fuel rail socket with the electrical connections facing outwards.
  6.  
  7. Rotate the injector retaining clip to the locked position.
  8.  
  9. Install the fuel rail assembly.
  10.  
  11. Tighten the fuel filler cap and connect the negative battery cable.
  12.  
  13. With the engine OFF , turn the ignition switch to the ON position for 2 seconds, then turn it to the OFF position for 10 seconds. Again, turn it to the ON position and check for fuel leaks.
  14.  

Specific to:

Buick LeSabre 1986-1999

Buick Park Avenue 1996-1999

Oldsmobile 88 1992-1999

Oldsmobile Delta 88 1986-1988

Oldsmobile LSS 1996-1999

Pontiac Bonneville 1987-1999

When servicing the fuel rail assembly, be careful to prevent dirt and other contaminants from entering the fuel passages. Fittings should be capped and holes plugged during servicing. At any time the fuel system is opened for service, the O-ring seals and retainers used with related components should be replaced.

Before removing the fuel rail, the fuel rail assembly may be cleaned with a spray type cleaner, GM-30A or equivalent, following package instructions. Do not immerse fuel rails in liquid cleaning solvent. Be sure to always use new O-rings and seals when reinstalling the fuel rail assemblies.

Specific to:

Buick LeSabre 1986-1995

Buick Park Avenue 1996-1999

Oldsmobile 88 1992-1995

Oldsmobile Delta 88 1986-1988

Pontiac Bonneville 1987-1995

  1. Disconnect the negative battery cable.
  2.  
  3. Relieve the fuel system pressure, as outlined earlier in this section.
  4.  
  5. Remove the intake manifold plenum, as required.
  6.  
  7. Disconnect the fuel feed and return lines at the fuel rail; be sure to use a back-up wrench on the inlet fitting to prevent turning or refer to the procedure for quick-connect fittings, located earlier in this section.
  8.  



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Fig. Remove any necessary wire ties by cutting them off ...



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Fig. ... in order to free up lines for disconnection



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Fig. Remove the bracket for access to the fuel lines



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Fig. Unfasten the clamps retaining the fuel lines



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Fig. Always use a back-up wrench when disconnecting fuel lines



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Fig. Place some paper towels under each fuel line connection to absorb any fuel that leaks out



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Fig. Move the fuel lines away from the rail assembly

  1. Remove and discard the fuel feed and return line O-rings.
  2.  
  3. Disconnect the vacuum line at the pressure regulator, as required. Remove the return line from the pressure regulator.
  4.  



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Fig. Disconnect the vacuum line from the fuel pressure regulator

  1. For 1995 VIN 1 engines, disconnect the vacuum line from the supercharger or the vacuum line from the throttle body for the 1995 VIN K engine.
  2.  
  3. For 1995 VIN K engines, tag and disconnect the ignition coil wires.
  4.  
  5. Either detach the fuel injector electrical connectors or unplug the main injector harness connector.
  6.  



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Fig. You can either unplug the entire injector wiring harness, or detach each injector connector as shown here



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Fig. Each injector connector has a retaining clip, which secures it to the injector

  1. Remove the fuel rail attaching bolts. Remove the fuel rail assembly, pulling up with equal forces on both sides of the rail. Note the location and routing of vacuum hoses around the fuel rail before removing the rail. Cover all openings with masking tape to prevent dirt from entering.
  2.  



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Fig. Unfasten the fuel rail assembly attaching nuts



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Fig. Pull the fuel rail assembly up, disengage the injectors, then remove the rail from the vehicle

If any injectors become separated from the fuel rail and remain in the intake manifold, both O-ring seals and injector retaining clip must be replaced. Use care in removing the fuel rail assembly, to prevent damage to the injector electrical connector terminals and the injector spray tips. When removed, support the fuel rail to avoid damaging its components. The fuel injector is serviced as a complete unit only. Since it is an electrical component, it should not be immersed in any type of cleaner.

  1. Remove the injector O-ring seal from the spray tip end of each injector. Discard the O-rings.
  2.  



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Fig. Exploded view of the fuel rail, regulator and injectors - 1995 VIN L engine shown



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Fig. Exploded view of the fuel rail assembly - 1995 VIN 1 engine shown



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Fig. Exploded view of the fuel rail, regulator and injectors - 1995 VIN K engine shown

To install:

  1. Lubricate new injector O-ring seals with clean engine oil and install on the spray tip end of each injector.
  2.  
  3. Position the fuel rail assembly on the intake manifold. Tilt the rail assembly to install the injectors, seating them by hand. Carefully push the injectors into the cylinder head intake ports until the bolt holes on the fuel rail and manifold are aligned. Install the fuel rail attaching bolts and fuel rail bracket bolts. Tighten the fuel rail attaching bolts, as follows:
    1. 1986-93 vehicles: 7-14 ft. lbs. (10-18 Nm).
    2.  
    3. 1994 3.8L (VIN L) engines: 8 ft. lbs. (12 Nm).
    4.  
    5. 1994 3.8L (VIN 1) engines: 22 ft. lbs. (30 Nm).
    6.  
    7. 1995 3.8L (VIN L) engines: 11 ft. lbs. (15 Nm).
    8.  
    9. 1995 3.8L (VIN 1) engines: 8 ft. lbs. (11 Nm).
    10.  
    11. 1995 3.8L (VIN K) engines: 7 ft. lbs. (10 Nm).
    12.  

  4.  
  5. Attach the injector electrical connectors or main injector wiring harness, as applicable. Rotate the injectors, as required, to prevent stretching the wire harness.
  6.  
  7. For 1995 VIN K engines, connect the ignition coil wires, as tagged during removal.
  8.  
  9. For 1995 VIN 1 engines, connect the vacuum line to the supercharger or connect the vacuum line to the throttle body for the 1995 VIN K engine, as applicable.
  10.  
  11. If disconnected, attach the vacuum line to the pressure regulator.
  12.  
  13. Install new O-rings on the fuel feed and return lines, then connect the fuel lines. Make sure to use a back-up wrench if necessary.
  14.  



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Fig. You should use a back-up wrench when tightening fuel line fittings

  1. Temporarily connect the negative battery cable to check for leaks as follows:
    1. Turn the ignition switch to the ON position for 2 seconds, then turn to the OFF position for 10 seconds. Again, turn the ignition switch to the ON position and check for fuel leaks.
    2.  

  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Install the intake manifold plenum.
  6.  
  7. Tighten the fuel filler cap.
  8.  
  9. Connect the negative battery cable.
  10.  

Specific to:

Buick LeSabre 1996-1999

Buick Park Avenue 1996-1999

Oldsmobile 88 1996-1999

Oldsmobile LSS 1996-1999

Pontiac Bonneville 1996-1999

  1. Properly relieve the fuel system pressure.
  2.  
  3. If not already done, disconnect the negative battery cable.
  4.  
  5. Remove the fuel feed and return pipes from the fuel rail tubes by squeezing the tabs and pulling the lines apart.
  6.  
  7. Disconnect the vacuum line from the pressure regulator. Tag and disconnect the vacuum lines from the throttle body.
  8.  
  9. For VIN K engines, tag and disconnect the ignition wires from the ignition coil.
  10.  
  11. For VIN 1 engines, tag and disconnect the ignition wires from the ignition coil and retainers clips on the top of the supercharger.
  12.  
  13. For the VIN 1 engine, remove the alternator and rear alternator mounting bracket.
  14.  
  15. Detach the injector electrical connectors.
  16.  
  17. If equipped, remove the injector electrical harness clips holding the harness to the front of the fuel rail.
  18.  

When working on the fuel rail, plug or cap the fuel lines and fuel passage openings to prevent dirt and debris from contaminating the system.

  1. Unfasten the fuel rail hold-down bolts. Remove the fuel rail by pulling it up with equal force on both sides of the rail.
  2.  



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Fig. Exploded view of the fuel rail mounting - 1997 3.8L (VIN 1) engine shown



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Fig. Exploded view of the fuel rail mounting - 1997 3.8L (VIN K) engine shown

To install:

  1. Lubricate new injector O-ring seals with clean engine oil and install on the spray tip end of each injector.
  2.  
  3. Position the fuel rail assembly on the intake manifold. Tilt the rail assembly to install the injectors, seating them by hand. Carefully push the injectors into the cylinder head intake ports until the bolt holes on the fuel rail and manifold are aligned. Install the fuel rail attaching bolts and fuel rail bracket bolts. Tighten the fuel rail attaching bolts to 7 ft. lbs. (10 Nm).
  4.  
  5. For the VIN 1 engine, install the rear alternator mounting bracket and alternator.
  6.  
  7. If equipped, fasten the injector electrical harness clips holding the harness to the front of the fuel rail.
  8.  
  9. Attach the injector electrical connectors.
  10.  
  11. Connect the ignition coil wires to the coil and, if equipped, install the retainer clips on top of the supercharger.
  12.  
  13. Connect the vacuum lines to the throttle body, as tagged during removal, and connect the line to the pressure regulator.
  14.  
  15. Install the fuel feed and return pipes to the fuel rail tubes by squeezing the tabs and pushing the lines on.
  16.  
  17. Temporarily connect the negative battery cable to check for leaks as follows:
    1. Turn the ignition switch to the ON position for 2 seconds, then turn to the OFF position for 10 seconds. Again, turn the ignition switch to the ON position and check for fuel leaks.
    2.  

  18.  
  19. Disconnect the negative battery cable.
  20.  
  21. Tighten the fuel filler cap.
  22.  
  23. Connect the negative battery cable.
  24.  

Specific to:

Buick Park Avenue 1998-1999

Oldsmobile Regency 1998

  1. Before servicing the vehicle, refer to the precautions in the beginning of this section.
  2.  
  3. Relieve the fuel system pressure.
  4.  
  5. Remove or disconnect the following:

    Negative battery cable
     
    Fuel lines
     
    Fuel rail
     
    Injector retaining clips
     
    Fuel injector

    Click image to see an enlarged view

    Fig. Exploded view of the fuel rail assembly-Vin 1 models



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    Fig. Exploded view of the fuel injector assembly

     

  6.  

To install:

  1. Install or connect the following:

    Fuel injector with new O-rings, coat the o-rings with clean engine oil prior to installation
     
    Injector retaining clips
     
    Fuel rail and torque the bolts to 7 ft. lbs. (10 Nm). On Vin 1 models, tighten the fuel rail hold down stud to 18 ft. lbs. (25 Nm).
     
    Fuel lines
     
    Negative battery cable
     

  2.  

Testing



Specific to:

Buick LeSabre 1986-1999

Buick Park Avenue 1996-1999

Oldsmobile 88 1992-1999

Oldsmobile Delta 88 1986-1988

Oldsmobile LSS 1996-1999

Pontiac Bonneville 1987-1999

The injectors can be tested by installing a "noid light," (a headlamp bulb may work) into the injector electrical connector, which confirms voltage when the light flashes.

  1. Start the engine and listen to each fuel injector individually for a clicking sound.
  2.  
  3. Turn the engine OFF and detach the electrical connector from the injector(s) that did not have a clicking sound.
  4.  
  5. Check the injector for continuity across the terminals. Compare the resistance value to a known good injector. The readings should be similar, if so proceed to the next step. If readings differ greatly, replace the injector.
  6.  



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Fig. Detach the fuel injector electrical connector ...



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Fig. ... then use an ohmmeter to check injector resistance. Compare with specifications from a known good injector

  1. Check between each injector terminal and ground. If continuity exists, replace the injector.
  2.  
  3. Detach the fuel injector connector and connect a noid light to the wiring harness connector. Crank the engine, while watching the light. Perform this test on at least two injectors before proceeding. If the light does not flash, check the injector power supply and ground control circuitry. If the light flashes proceed to the next step.
  4.  
  5. If the light flashes, remove the fuel rail from the engine and following the procedure below check the injector operation:
    1. Using mechanic's wire, secure the injector to the fuel rail.
    2.  
    3. Place a clear plastic container around each injector.
    4.  

  6.  


CAUTION
Prior to performing this test, all fuel safety precautions must be followed. Make certain the container is approved to handle fuel and is securely positioned around the injector. Do NOT use a glass container. Glass containers can be easily damaged, resulting in a serious fire hazard.

    1. With the help of an assistant or using a remote starter button, crank the engine for 9 seconds while observing the injector operation. The injector should produce a cone shaped spray pattern and all containers should retain equal amounts of fuel.
    2.  
    3. Once the cranking test is complete, leave the fuel rail pressurized and observe the injectors for leakage.
    4.  


  1. Replace any injector which is leaking or fails to provide a cone shaped spray pattern when energized.
  2.  

 
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