Unfortunately there really is no way of clean out a catalytic converter. There is a misconception of revving the engine hard to blow high volumes of exhaust through the tailpipe in an effort to dislodge carbon buildup within the CAT, and at times vehicle owners are able to prove this correct. However, if in fact one is successful in doing this, the material exiting the tailpipe will more than likely be the catalytic converter's melted or damaged substrate (high in carbon buildup) as opposed to any carbon material plugging up the CAT; and causing it to function poorly. If there is material coming out the tailpipe when you rev the engine, the catalytic converter is already shot. Getting more substrate out will eventually empty out the cat and make it a hollow shell.
A working catalytic converter should be able to reduce the emission levels of hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx). The catalytic converter only begins working after exhaust has exited the engine's combustion chambers. When hot exhaust gases are forced through the catalytic converter, they contact the catalyst substrate. This causes a rapid increase in temperature, causing exhaust gases to burn hotter, ultimately reducing emissions. The catalyst substrate must be free and clear of carbon in order to function efficiently. For the catalytic converter to have a healthy substrate it is pertinent that the engine be running as efficiently as possible at all times. Should the engine be emitting high levels of CO (rich fuel), the catalyst will become saturated with CO, it will deteriorate.
The life-span of a vehicle's catalytic converter will depend on how completely the engine burns fuel before presenting it the to the cat and also on the quality of the cat. Factory CATs should normally last 7 to 10 years. Catalytic converter failures most often occur on vehicles which have been poorly maintained and which have produced high emissions in any one or more of the emission categories (HC, CO or NOx).
We include below a quick guide to tell whether or not your vehicle's catalytic converter is defective.
Symptoms of a Defective Catalytic Converter:
- Symptom: Loss of engine power over 15-20 miles per hour.
Fault: CAT is plugged up and restricting exhaust flow.
- Symptom: Strong sulfur (egg) smell from good running engine.
Fault: Catalyst not completing the burning process properly.
- Symptom: Rattle being heard from CAT during idle and acceleration.
Fault: Catalytic substrate broken down and possibly plugged.
