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    Nissan Sentra/Pulsar/NX 1982-1996 Repair Guide

    Idle Speed Adjustment

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    CARBURETED ENGINES




    CAUTION
    When checking the idle speed, set the parking brake and block the drive wheels.

    E15 and E16 Engines

    See Figure 1



    Click image to see an enlarged view

    Fig. Fig. 1: Idle speed adjusting screw-carbureted engines

    1. Connect a tachometer to the engine according the manufacturer's instructions.
    2.  
    3. Start the engine and run it until it reaches normal operating temperatures.
    4.  
    5. Operate it at idle for 2 minutes under no-load, then race to 2,000-3,000 a few times and allow it to return to idle speed.
    6.  
    7. Turn OFF the engine.
    8.  

    For USA models, disconnect the vacuum control modulator harness connector. For Canada models, disconnect and plug the air induction hose at the air filter; also, for Canada models (1984-86), disconnect and plug the throttle opener control valve vacuum hose at the throttle opener control valve side.

    1. Start the engine and check the idle speed.
    2.  

    If the cooling fan is operating, wait until it stops.

    1. If equipped with a manual transaxle, place the shift selector in NEUTRAL ; if equipped with an automatic transaxle, place the shift selector in DRIVE .
    2.  
    3. If the idle speed is not correct, adjust the throttle adjusting screw at the carburetor.
    4.  
    5. When the idle speed is correct, stop the engine, reconnect the vacuum control modulator and the throttle opener control valve vacuum hose (if equipped), then disconnect the tachometer.
    6.  

    FUEL INJECTED ENGINES



    E16i Engine

    See Figure 2



    Click image to see an enlarged view

    Fig. Fig. 2: Idle speed adjusting screw-E16I engine

    1. Connect a tachometer to the engine, according to the manufacturer's instructions.
    2.  
    3. Start and operate the engine until it reaches normal operating temperatures. Operate the engine for 5 minutes under no load.
    4.  

    Engage the parking brake and block the drive wheels. If equipped with a manual transaxle, place the shift selector in the NEUTRAL position. If equipped with an automatic transaxle, place the shift selector in the DRIVE position.

    1. Check and/or adjust the engine speed. If necessary to adjust, turn the idle speed adjusting screw on the Idle Air Adjusting (IAA) unit.
    2.  
    3. With the idle speed adjusted, stop the engine and disconnect the tachometer.
    4.  

    E15ET Engine

    See Figure 3



    Click image to see an enlarged view

    Fig. Fig. 3: Idle speed adjusting screw-E15ET engine

    1. Connect a tachometer to the engine, according to the manufacturer's instructions.
    2.  
    3. Start and run the engine until it reaches normal operating temperatures. Operate the engine at 2,000 rpm, for 2 minutes under no-load.
    4.  
    5. Race the engine to 2,000-3,000 rpm a few times and allow it to go to idle speed.
    6.  

    Engage the parking brake and block the drive wheels. If equipped with a manual transaxle, place the shift selector in the NEUTRAL position. If equipped with an automatic transaxle, place the shift selector in the DRIVE position.

    1. Check and/or adjust the engine speed. If necessary to adjust, turn the throttle adjusting screw in the idle control valve.
    2.  
    3. With the idle speed adjusted, stop the engine and disconnect the tachometer.
    4.  

    CA16DE and CA18DE Engines

    See Figures 4, 5 and 6



    Click image to see an enlarged view

    Fig. Fig. 4: Idle Air Adjusting (IAA) unit-CA16DE and CA18DE engines



    Click image to see an enlarged view

    Fig. Fig. 5: Idle speed adjusting screw-CA16DE and CA18DE engines



    Click image to see an enlarged view

    Fig. Fig. 6: Tachometer hook-up using a suitable tool

    1. Before adjusting the idle speed on these engines, visually check the following items:

      air cleaner for clogs
       
      hoses and ducts for leaks
       
      EGR valve for proper operation
       
      all electrical connectors, gaskets and the throttle valve
       
      throttle valve switch (CA16DE engine only)
       
      idle switch (CA18DE engine only)
       

    2.  
    3. Start the engine and warm the engine so it reaches normal operating temperature. The water temperature indicator should be in the middle of the gauge.
    4.  
    5. Then race the engine to 2,000-3,000 rpm a few times under no load and then allow it to return to the idle speed.
    6.  
    7. Connect a voltage type tachometer to the engine by using a suitable type tool in the check connector for a lead outlet.
    8.  
    9. Check the idle speed on the manual transaxle model in NEUTRAL and on the automatic transaxle model check in DRIVE .
    10.  
    11. If the idle speed has to be adjusted you must disconnect the Auxiliary Air Control (AAC) valve harness connector.
    12.  
    13. Adjust the idle speed by turning the idle speed adjusting screw on the Idle Air Adjusting (IAA) unit.
    14.  
    15. Recheck the engine idle speed.
    16.  

    GA16i, GA16DE and SR20DE Engines
    1. Before adjusting the idle speed on these engines you must visually check the following items first: air cleaner for being clogged, hoses and ducts for leaks, EGR valve for proper operation, all electrical connectors, gaskets and the throttle valve and throttle valve switch.
    2.  
    3. Start the engine and warm the engine so it reaches normal operating temperature. The water temperature indicator should be in the middle of the gauge.
    4.  
    5. Then race the engine to 2,000-3,000 rpm a few times under no load and then allow it to return to the idle speed.
    6.  
    7. Connect a voltage type tachometer to the engine by using a suitable type tool in the check connector for a lead outlet.
    8.  
    9. Check the idle speed with the transaxle in NEUTRAL .
    10.  
    11. Turn the engine OFF and disconnect the throttle valve switch at the throttle body assembly.
    12.  
    13. Start the engine and check idle speed. If not within specifications, turn the idle adjusting screw at the throttle body until idle is within specifications. Race the engine to 2,000-3,000 rpm and recheck the idle speed.
    14.  
    15. Turn the engine OFF and reconnect the throttle valve switch.
    16.  

    DIESEL ENGINE



    CD17 Engine

    See Figures 7 and 8



    Click image to see an enlarged view

    Fig. Fig. 7: Loosen the idle screw locknut while holding the control lever



    Click image to see an enlarged view

    Fig. Fig. 8: Turn the idle speed adjusting screw to obtain the specified rpm

    A special tachometer compatible with diesel engines will be required for this procedure. A normal tachometer will not work.

    1. Make sure all electrical accessories are turned off.
    2.  
    3. The automatic transmission (if so equipped) should be in "D'' with the parking brake on and the wheels blocked.
    4.  
    5. Start the engine and run it until it reaches the normal operating temperature.
    6.  
    7. Attach the diesel tachometer's pickup to the No. 1 injection tube.
    8.  

    In order to obtain a more accurate reading of the idle speed, you may wish to remove all the clamps on the No. 1 injection tube.

    1. Run the engine at about 2,000 rpm for two minutes under no-load conditions.
    2.  
    3. Slow the engine down to idle speed for about 1 minute, then check the idle.
    4.  
    5. If the engine is not idling at the proper speed, turn it off and disconnect the accelerator wire from the injection pump control lever.
    6.  

    It is not necessary to disconnect the accelerator wire on the CD17 engine.

    1. Move the control lever to the full acceleration side, and then loosen the idle screw locknut while still holding the control lever.
    2.  
    3. Start the engine again and turn the adjusting screw until the proper idle is obtained. Stop the engine.
    4.  
    5. Tighten the idle adjusting screw locknut while still holding the control lever to the full acceleration side, then connect the accelerator wire.
    6.  

     
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