Jeep Wrangler/YJ 1987-1995 Repair Guide

Oxygen Sensor

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See Figures 1 and 2



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Fig. Fig. 1: Heated oxygen sensor-1987-90 with the 2.5L engine



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Fig. Fig. 2: Common oxygen sensor location-all engines

The oxygen sensor is located in the exhaust manifold and provides input to the ECU relating oxygen content of the exhaust gas. The ECU uses this information to vary air/fuel ratio. A lean air/fuel mixture causes a greater oxygen content and a rich air/fuel mixture causes less oxygen content. On 1987-90 2.5L engines, the oxygen sensor is equipped with an electrically heated element that keeps the sensor at operating temperature under all conditions.

REMOVAL & INSTALLATION



See Figures 3 and 4



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Fig. Fig. 3: Disengaging the oxygen sensor harness connector



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Fig. Fig. 4: Removing the oxygen sensor from the exhaust pipe

  1. Raise the vehicle and support it safely. Allow the exhaust system to cool sufficiently in order to permit servicing without burning yourself.
  2.  
  3. Disengage the wire connector from the oxygen sensor.
  4.  
  5. Remove the oxygen sensor from the exhaust manifold.
  6.  
  7. If not already done, coat the threads of the replacement sensor with anti-seize compound. Be careful not to contaminate the oxygen sensor probe with the anti-seize.
  8.  
  9. Install the oxygen sensor into the exhaust manifold and tighten to 22-35 ft. lbs. (30-47 Nm) Engage the wire connector.
  10.  

 
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