Nissan Sentra/Pulsar/NX 1982-1996 Repair Guide

Air/Fuel Mixture Solenoid

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OPERATION



See Figures 1 and 2



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Fig. Fig. 1: Air/Fuel mixture control system operation-solenoid valve energized



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Fig. Fig. 2: Air/Fuel mixture control system operation-solenoid valve de-energized

The air/fuel mixture solenoid provides a method of controlling the amount of fuel supplied to the engine, throughout all engine operating conditions. By monitoring the inputs from various sensors, the ECM can vary the ON or OFF time of the solenoid; this in known as the duty cycle. By continually adjusting the duty cycle every 65 milli-seconds, the optimum air/fuel mixture, for all engine conditions, can be provided.

TESTING



  1. Turn off ignition and disconnect air/fuel ratio solenoid harness connector.
  2.  
  3. Measure the resistance of the solenoid. The resistance should be 30-50 ohms. If air/fuel solenoid resistance is out of specification, replace solenoid assembly.
  4.  
  5. If solenoids are within specifications, reconnect solenoid harness connectors.
  6.  
  7. Disconnect ECM 10 pin connector from control unit and disconnect alternator L terminal.
  8.  
  9. Turn ignition switch ON and measure voltage between terminal F and ground.

    If battery voltage is not present, check and (if necessary) repair/replace harness.
     
    If voltage is within specification, check and (if necessary) replace control unit.
     

  10.  

REMOVAL & INSTALLATION



See Figures 3 and 4



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Fig. Fig. 3: Remove the two mounting screws and pull the solenoid from the carburetor housing



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Fig. Fig. 4: When removing or replacing the Air/Fuel mixture solenoid, always install new O-rings

  1. Drain approximately one quart of engine coolant.
  2.  
  3. Remove carburetor from engine.
  4.  
  5. Disconnect harness from harness connector and cut the harness cover at the connector.
  6.  
  7. Remove choke chamber assembly from carburetor.
  8.  
  9. Remove air/fuel ratio solenoid from choke chamber.
  10.  

To install:
  1. Use new O-rings on solenoid and apply a light coating of oil to O-rings.
  2.  
  3. Install solenoid and torque mounting bolts to 12-36 inch lbs. (1.5-4 Nm).
  4.  
  5. Install choke chamber assembly.
  6.  
  7. Install new boots and terminal ends to harness with terminal pliers, and then place terminals in connector.
  8.  

 
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