While many people seem to enjoy the idea of eliminating their catalytic converter, it is an essential part of the automotive emissions system. The catalytic converter works to change toxic pollutants into less toxic CO2 and water. When such an important mechanism is failing or has failed there are some symptoms to look for.
Poor Performance
Better flowing exhaust can translate into increased performance. A clogged or obstructed exhaust system will leave your car underperforming both on the road and at the pump. If no air can exit the system then there is an equally good chance none can enter properly either. The catalytic converter is comprised of many small passages made from a ceramic honeycomb shaped extrusion coated in a multitude of metals and other elements. Poor performance would be causing a lack of acceleration due to decreased flow. The need for more throttle input would net you noticeably less fuel mileage. This higher then normal throttle input can start to really heat things up under the car. Shown below is an example of a severly clogged cat that is glowing red hot.
CEL
A check engine light may be illuminated indicating that something else is wrong as a result of a failed or failing catalytic converter. A very noticeable example of this could be a random misfire caused by the improper evacuation of one or multiple cylinders. You would likely experience this under load at first and then lower and lower down the rev range if the clogging continued.
Some useful generic Volvo 99+ CEL codes:
(Codes given in ISO/SAE format to show what a generic reader or auto store would give) Remember to explore every option before throwing parts at a problem.
P0102 - MAF Sensor - Flow too low Intermittent fault (bad flow into the system on a known good MAF)
P0300 - Misfire on at least one cylinder (Check plugs for excessive wear/corrosion)
P0420/30 Three-way catalytic converter intermittent/permanent fault. (Oxygen sensors may be at fault for this)
No Start
In an extreme case you may even begin to experience no start issues. This is caused by not enough or not air entering into the car's engine because none can get out.
Inspection and Prevention
On the Volvo V70 (P80 platform) as well as many other cars, visual inspection of the catalytic converter can be cumbersome. With an inspection camera it would be possible to get a close up look after removing the front and or rear O2 sensor. However, the sensors are fragile in nature and improper removal techniques can leave you in a tight spot, so use caution and the proper tools. Removing the mid-pipe may also be an option.
Thankfully regular maintenance and attention to detail will allow a catalytic converter to last a lifetime like it is supposed to. Unburnt fuel as a result of fouled spark plugs or a malfunctioning ignition system can contribute to premature failure. Using the improper grade fuel can leave extra fuel in the exhaust path as well. The system is intended to work within a normal set of variables and big changes can upset this. White smoke as a result of coolant traveling down the exhaust path, either from the cylinder head or turbo will upset the balance again and result in potential failure.
If you have any bad cat horror stories I would love to hear your comments.
