GM Cutlass RWD 1970-1987 Repair Guide

Catalytic Converter


See Figures 1, 2 and 3

The catalytic converter is a muffler-like container built into the exhaust system to aid in the reduction of exhaust emissions. The catalyst element consists of individual pellets or a honeycomb monolithic substrate coated with a metal such as platinum, palladium, rhodium or a combination of these. When the exhaust gases come into contact with the catalyst, a chemical reaction occurs which will reduce the pollutants into harmless substances like water and carbon dioxide.

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Fig. Fig. 1: Bead type catalytic converter

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Fig. Fig. 2: Dual bed type catalytic converter

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Fig. Fig. 3: Single bed monolith type converter

On these models, lead-free fuel must be used exclusively in order to prevent the converter from being coated with lead particles, rendering it ineffective. However, there are many other precautions which should be taken to prevent a large amount of unburned hydrocarbons from reaching the converter. Should a sufficient amount of HC reach the converter, the unit could overheat, damaging the converter, nearby mechanical components, and/or causing a fire hazard. Therefore, when working on your car, the following conditions should be avoided:

  1. The use of fuel system cleaning agents and additives.
  3. Operating the car with an inoperative (closed) choke, or submerged carburetor float.
  5. Extended periods of idling.
  7. Turning OFF the ignition with the car in motion.
  9. Ignition or charging system failure.
  11. Misfiring of one or more spark plugs.
  13. Disconnecting a spark plug wire while testing for bad wire, plug, or poor compression in one cylinder.
  15. Push or jump starting the car, especially when hot.
  17. Pumping the gas pedal when attempting to start a hot engine.