Nissan Sentra/Pulsar/NX 1982-1996 Repair Guide

Catalytic Converter

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OPERATION



This system is used on all models, except 1982-86 Canada models. The catalytic converter is a muffler-like container built into the exhaust system. The catalyst element consists of individual pellets or a honeycomb monolithic substrate coated with a noble metal such as platinum, palladium, rhodium or a combination. When the exhaust gases come into contact with the catalyst, it changes residual HC, CO and NOx in the exhaust gas into CO 2 , H 2 O and N, before the exhaust gas is discharged into the atmosphere.

Regular maintenance is not required for the catalytic converter system, except for periodic replacement of the Air Induction System filter (if equipped). The TWC converter is non-serviceable and may only be replaced if found to be defective or clogged.

PRECAUTIONS



  1. Use ONLY unleaded fuel.
  2.  
  3. Avoid prolonged idling; the engine should run no longer than 20 min. at curb idle and not longer than 10 min. at fast idle.
  4.  
  5. Do not disconnect any of the spark plug leads while the engine is running.
  6.  
  7. Make engine compression checks as quickly as possible.
  8.  

TESTING



  1. Carefully lift and safely support the front of the vehicle.
  2.  


CAUTION
If the engine has run recently, the TWC converter will be very hot. Do not touch.

  1. Carefully remove the TWC converter.
  2.  
  3. With a light at one end of the TWC converter, look through from the other end and inspect the element for clogging. If no light is able to pass through the converter, the catalyst is either clogged or melted.
  4.  
  5. If the light is able to pass through, the TWC converter is okay.
  6.  

REMOVAL & INSTALLATION



  1. Carefully lift and safely support the front of the vehicle.
  2.  


CAUTION
If the engine has run recently, the TWC converter will be very hot. Do not touch.

  1. Spray the retaining bolts with a loosening agent.
  2.  
  3. If necessary, remove the O 2 S or HO 2 S sensor.
  4.  
  5. Remove the nuts and bolts, along with the heat shields.
  6.  
  7. Pull the rear exhaust pipe back and remove the TWC. Discard the gaskets.
  8.  

To install:
  1. Position the TWC to the exhaust ends with new gaskets. Secure with nuts and bolts.
  2.  
  3. Install the heat shields, then tighten the retaining bolts.
  4.  
  5. If the O 2 S or HO 2 S was removed, coat the threads with an approved anti-seize compound and install the sensor.
  6.  
  7. Lower the vehicle. Start engine and check for exhaust leaks.
  8.  

 
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