DESCRIPTION & OPERATION
Note. Light Duty Emission vehicles are those vehicles whose Gross Vehicle Weight (GVW) does not exceed 8500 lbs.
The catalytic converter(s) is installed in the exhaust system in front of the muffler, so that all exhaust gas must pass through the converter(s). The converter is a stainless steel muffler-shaped device that reduces exhaust emissions.
The catalyst reduces hydrocarbons (HC) and carbon monoxide (CO) emissions. The material inside the converter is 1 of 2 types: a coated 1-piece honeycombed block (monolithic type), or small beads of catalyst-coated material.
Note. Use ONLY unleaded fuel in vehicles using catalytic converters. If leaded fuel is used, the Tetra Ethel Lead will coat the palladium, platinum and rhodium, rendering these catalysts inoperative. If this happens, the converter must be replaced.
HEAT SHIELDS
The combustion reaction, which is furthered by the converter, releases additional heat. Temperature in the catalytic converter can reach 1600°F (871°C) under normal conditions. Special heat shields are used to protect underbody and components from this extreme heat.
MAINTENANCE
There is no scheduled maintenance required for catalytic converters. However, on Jeep models with bead-type converters, bead removal and replacement is possible.
CATALYST REPLACEMENT
- Raise vehicle, and attach vacuum aspirator (J-25077-01 or equivalent) to exhaust pipe. (Scheme 26)
- Apply enough air pressure, minimum 80 lbs. (36 kg) to hold catalyst beads in place while converter fill plug is removed.
- Clamp on vibrator and catalyst receptacle. (Scheme 27) Disconnect air supply from vacuum aspirator, and attach it to vibrator unit.
- Using air pressure, vibrator should operate and empty the converter of the catalytic beads in about 10 minutes.
- When all catalyst material is removed, disconnect air supply, and remove container from converter. Discard beads.
- Fill container with approved replacement catalyst, and install a fill tube fixture to the vibrator device.
- Attach air supply to both vibrator and aspirator. With container attached to fill tube, catalyst will begin to move into converter.
- When catalyst stops flowing, disconnect air supply to vibrator, and note level of catalyst. It should be even with fill plug. Add more catalyst, if required.
- Apply nickle-base, anti-seize compound to fill plug. Install plug and tighten to 60 ft. lbs. (82 N.m). If equipped with press-type fill plug, install "bridge-and-bolt" type service plug and torque to 28 ft. lbs. (37 N.m).
