GM Cadillac 1967-1989 Repair Guide

EFI Component Service

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ADJUSTMENTS



Idle speed

Before low idle speed adjustment is made distributor vacuum advance hose(s) must be disconnected at the distributor and plugged. The hose must be disconnected at this location to include any calibrated leakage in balance of the system. Reset timing before making idle speed adjustment.

  1. Disconnect parking brake hose at vacuum release cylinder and plug the hose. Set the parking brake and block the wheels. Disconnect the air leveling compressor hose at air cleaner and plug the hose.
  2.  
  3. Connect a tachometer, start and warm-up the engine to operating temperature.
  4.  
  5. Place the transmission in drive and turn the air conditioner off.
  6.  
  7. Loosen the lock nut on the idle bypass adjusting screw on the front of the throttle body.
  8.  
  9. Adjust the idle bypass adjusting screw to give 650 rpm.
  10.  
  11. Tighten the lock nut.
  12.  
  13. Turn off the engine and remove the tachometer.
  14.  
  15. Reconnect all hoses.
  16.  

Throttle Position Switch

  1. Loosen two throttle position switch mounting screws to permit rotation of the switch.
  2.  
  3. Hold the throttle valves in the idle position while performing step 3 and 4.
  4.  
  5. Turn the throttle position switch carefully counterclockwise until the endstop has been reached.
  6.  
  7. Tighten throttle position switch mounting screws to 11 inch lbs. (1.2 Nm).
  8.  
  9. Check to insure that throttle valves close to the throttle stop. If not, repeat steps 2, 3 and 4.
  10.  

REMOVAL & INSTALLATION



Electronic Control Unit/Module (ECM/ECU)

SEVILLE



  1. Disconnect the negative battery cable.
  2.  
  3. Loosen the right-hand forward screw which secures the ECU cover to the ECU.
  4.  
  5. Remove the three remaining screws.
  6.  
  7. Remove the screws which secure the ECU to the instrument panel supports.
  8.  
  9. Carefully lower the ECU enough to disconnect three electrical connectors from the left hand side and the MAP hose from the front of the ECU.
  10.  
  11. Remove the ECU.
  12.  
  13. Installation is the reverse of removal.
  14.  

EXCEPT ELDORADO AND SEVILLE

See Figure 1

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the glove box liner.
  4.  
  5. Remove the ECU mounting screws and remove the ECU.
  6.  
  7. Disconnect the three electrical connectors (red, black and blue) and the MAP sensor hose.
  8.  
  9. Installation is the reverse of removal.
  10.  



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Fig. Fig. 1: ECU mounting

ELDORADO

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the three climate control outlet grilles right, left and center.
  4.  
  5. Working through the outlet openings, remove the three fasteners securing the pad to the instrument panel support.
  6.  
  7. Remove the screws securing the pad to the instrument panel horizontal support.
  8.  
  9. Pull the pad outward and disconnect the electrical connector from the windshield wiper switch.
  10.  
  11. Remove the pad.
  12.  

To facilitate removal and/or installation place the shift lever in low range. Vehicles equipped with tilt wheel, place the wheel in the lowest position.

  1. Remove the MAP sensor hose.
  2.  
  3. Remove the mounting screws and then the ECU.
  4.  
  5. Remove the electrical connectors.
  6.  
  7. Installation is the reverse of removal.
  8.  

Throttle Body Assembly

See Figures 2, 3, 4, 5, 6, 7, 8, 9 and 10

  1. Remove the air cleaner.
  2.  
  3. Disconnect the throttle return springs from the throttle lever.
  4.  
  5. Remove the retainer and remove the cruise control chain from the throttle lever on cars so equipped.
  6.  
  7. Remove the hairpin clip and disconnect the throttle cable.
  8.  
  9. Remove the rear throttle body mounting screws and position the throttle linkage out of the way.
  10.  
  11. Disconnect the throttle position switch electrical connector and fast idle valve electrical connector. Slide the fast idle valve wiring out of the notch in the throttle body.
  12.  
  13. Remove the vacuum hoses from the nipples on the throttle body. Use a backup wrench when removing the power brake vacuum line.
  14.  
  15. Remove the remaining throttle body mounting screws and remove the throttle body.
  16.  

To install:
  1. Remove the gasket material from the intake manifold and bottom of the throttle body.
  2.  
  3. The following parts are not included in a new throttle body assembly and should be removed as needed. Throttle position switch, fast idle valve seat, fast idle valve spring, fast idle valve, fast idle valve heater assembly, power brake vacuum fitting.
  4.  
  5. Installation is the reverse of removal.
  6.  



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Fig. Fig. 2: Throttle body mounting



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Fig. Fig. 3: View of the throttle body assembly



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Fig. Fig. 4: Removing external pedal linkage



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Fig. Fig. 5: Installing external pedal linkage



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Fig. Fig. 6: Removing line from the throttle body



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Fig. Fig. 7: Removing electrical connections from the throttle body



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Fig. Fig. 8: Removing all necessary electrical connections



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Fig. Fig. 9: Removing electrical connections from the side of the throttle body



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Fig. Fig. 10: Removing the throttle body assembly

Fast Idle Valve
  1. Remove the air cleaner and disconnect the electrical connector from the fast idle valve heater.
  2.  
  3. Remove the air cleaner stud.
  4.  
  5. Remove the fast idle valve heater by pushing down and twisting 90 degrees counterclockwise.
  6.  
  7. Remove the fast idle valve, spring and seat from the throttle body.
  8.  
  9. Installation is the reverse of removal.
  10.  

Fuel RailEXCEPT SEVILLE

  1. Remove and discard the hose clamp securing the pressure regulator hose to the front fuel rail.
  2.  
  3. Using a back-up wrench at the side rail fitting, remove the flare nut from each end of the fuel rail.
  4.  
  5. Disengage the front rail from the pressure regulator hose and remove it from the vehicle.
  6.  
  7. Installation is the reverse of removal.
  8.  

Injection ValveSEVILLE ONLY

  1. Disconnect the electrical leads from all injectors on the fuel rail being removed and position the harness out of the way.
  2.  
  3. Remove the fuel inlet line from the fuel rail using a back-up wrench.
  4.  
  5. Remove the return hose and vacuum hose from the pressure regulator.
  6.  
  7. Disconnect the fuel rail from the fuel regulator.
  8.  
  9. Remove the screw holding each injector bracket to the intake manifold, and remove the brackets and grommets.
  10.  
  11. Remove the fuel rail and injectors from the engine as a complete unit.
  12.  

Some injectors may stick in the fuel rail while others may remain in the manifold.

  1. Remove the injectors from the fuel rail and from the intake as required.
  2.  
  3. Injection valves are sealed by O-rings at the fuel rail and intake manifold. Remove and discard all used O-rings.
  4.  
  5. Installation is the reverse of removal.
  6.  

A conical shaped metal gasket should be used when servicing EFI fuel rail fittings. The gasket Part #1608786 or its equal is not required during production, but is needed during service procedures. This gasket should be inserted in the fuel rail inverted flare fitting each time a fitting is separated and reconnected in the field. These gaskets can not be re-used.ALL OTHERS

  1. Remove the front and rear fuel rails.
  2.  
  3. Remove the electrical conduit from the injector brackets (4 places on each side).
  4.  
  5. Disconnect the electrical leads from all injectors on the fuel rail being removed.
  6.  
  7. Remove the two screws holding each injector bracket to the intake manifold and remove the brackets and grommets.
  8.  
  9. Remove the fuel rail and injector from the engine as a unit. Some injectors may stick in the fuel rail while others may remain in the manifold.
  10.  
  11. Remove the injectors from the fuel rail and from the intake manifold as required.
  12.  
  13. Injection valves are sealed by O-rings at both fuel rail and intake manifold. Remove and discard all used O-rings.
  14.  
  15. Installation is the reverse of removal. Lubricate the new O-rings prior to installation.
  16.  

Fuel Pressure Regulator
  1. Remove the vacuum hose from the nipple on top of the pressure regulator.
  2.  
  3. Remove and discard clamps securing the flexible fuel hose connecting the regulator to the fuel rail. Remove the return line.
  4.  
  5. Remove one nut securing the pressure regulator to the bracket.
  6.  

This nut has metric threads.

  1. Work the regulator off the flexible fuel hose and out of the bracket.
  2.  
  3. Installation is the reverse of removal.
  4.  

Throttle Position Switch

  1. Remove the electrical connections from the switch.
  2.  
  3. Remove the two mounting screws and remove the switch from the throttle body.
  4.  
  5. Installation is the reverse of removal. Adjust the switch as necessary.
  6.  

Coolant Temperature Sensor

  1. Drain the radiator.
  2.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Locate the water temperature sensor in the heater hose outlet at the rear of the right hand cylinder head.
  2.  
  3. Disconnect the electrical connector from the sensor.
  4.  
  5. Remove the sensor from the heater hose.
  6.  
  7. Installation is the reverse of removal.
  8.  

Air Temperature Sensor

  1. Locate the sensor at the right rear of the intake manifold.
  2.  
  3. Disconnect the sensor from its electrical connector.
  4.  
  5. Remove the sensor from the intake manifold.
  6.  
  7. Installation is the reverse of removal. Coat the sensors threads with a non-hardening sealer prior to reinstallation.
  8.  

 
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