GM Bonneville/Eighty Eight/LeSabre 1986-1999

Fuel Rail Assembly

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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.

REMOVAL & INSTALLATION



1987-95 Vehicles

See Figures 1 through 16

  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. Fig. 1: Remove any necessary wire ties by cutting them off ...



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Fig. Fig. 2: ... in order to free up lines for disconnection



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Fig. Fig. 3: Remove the bracket for access to the fuel lines



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Fig. Fig. 4: Unfasten the clamps retaining the fuel lines



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Fig. Fig. 5: Always use a back-up wrench when disconnecting fuel lines



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Fig. Fig. 6: Place some paper towels under each fuel line connection to absorb any fuel that leaks out



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Fig. Fig. 7: 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. Fig. 8: Disconnect the vacuum line from the fuel pressure regulator

  1. For 1795 VIN 1 engines, disconnect the vacuum line from the supercharger or the vacuum line from the throttle body for the 1795 VIN K engine.
  2.  
  3. For 1795 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. Fig. 9: You can either unplug the entire injector wiring harness, or detach each injector connector as shown here



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Fig. Fig. 10: 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. Fig. 11: Unfasten the fuel rail assembly attaching nuts



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Fig. Fig. 12: 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. Fig. 13: Exploded view of the fuel rail, regulator and injectors - 1995 VIN L engine shown



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Fig. Fig. 14: Exploded view of the fuel rail assembly - 1995 VIN 1 engine shown



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Fig. Fig. 15: 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 1795 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. Fig. 16: 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.  

1996-99 Vehicles

See Figures 17 and 18

  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. Fig. 17: Exploded view of the fuel rail mounting - 1997 3.8L (VIN 1) engine shown



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Fig. Fig. 18: 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.  

 
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