Catalytic Converter

Introduction Of Catalytic Converters There are millions of cars on the road in the United States, and each one is a source of air pollution. Especially in large cities, the amount of pollution that all the cars produce together can create big problems.

To solve those problems, cities, states and the federal government create clean-air laws that restrict the amount of pollution that cars can produce. Over the years, automakers have made many refinements to car engines and fuel systems to keep up with these laws. One of these changes came about in 1975 with an interesting device called a catalytic converter. The job of the catalytic converter is to convert harmful pollutants into less harmful emissions before they ever leave the car's exhaust system.

Catalytic converters also have other environmental and health benefits. They cut down the amount of the poisonous gas carbon monoxide leaving the exhaust pipe. Catalytic converters also cut down on the amount of nitrous oxides that enter the atmosphere. Nitrous oxides are the primary cause of smog and acid rain.

It should be remembered that while catalytic converters filter out the most harmful substances they still release gases that are harmful to the atmosphere, like carbon dioxide.

How Does It Work?
The catalytic converter usually consists of a honeycomb structured ceramic monolith, which is surrounded by matting. The matting holds the monolith securely in place and provides a cushion against road shock and vibration. This is all encased in a steel shell to provide further protection. Another option is a steel monolith, which is more durable. The steel monolith we supply has a texture similar to cotton wool.

The catalytic converter is situated in the exhaust pipe, usually close to the manifold. This is because the catalyst needs to reach a certain temperature before it starts to operate properly; so the closer it is to the engine the quicker it reaches operating temperature.

There are several things you can do to ensure your CAT has a long and healthy life:

1. When fitting the catalytic converter don’t use exhaust paste in front of the cat. When the exhaust paste hardens it can break off in chunks and destroy the monolith.

2. Always use the correct fuel for your car.

3. Never use a fuel additive without first reading the instructions to find out if it is suitable for use with a catalytic converter. If in doubt, consult the manufacturer of the additive.

4. Never attempt to bump or tow start your car. This causes unburned fuel to be injected into the cat, which makes the monolith overheat and melt.

5. Never tow anything that is too heavy for your vehicle to cope with. For example, an overloaded caravan will actually push a car along when it travels downhill. This sends unburned fuel into the exhaust system and can cause the monolith to melt down.

6. Have your car regularly serviced to your car manufacturers specifications. In particular make sure the engine is running properly. A poorly tuned engine can cause the monolith to break down or become covered in soot, which stops it working correctly.

7. Take care when driving through deep puddles, fords, or parking when there has been heavy snow. The cat operates at an extremely high temperature, and when it comes into contact with water or snow it cools down rapidly. The steel shell cools more rapidly than the monolith, and in extreme circumstances the monolith can be crushed as the steel shell contracts.

8. Don’t park your car over long grass or anything similar. As the cat operates at such a high temperature it can actually set the grass on fire!

9. Drive slowly over speed bumps or very bumpy roads to reduce the chance of the exhaust system being grounded. This could cause impact damage to the cat.

Warranty Information
Although every effort is made to ensure our catalytic converters will not fail, sometimes a problem with the vehicle will cause them to break down. The following problems are NOT covered by our guarantee:

Road Damage
This is external damage caused to the catalytic converter by hitting solid objects in the road. i.e., speed bumps, large rocks etc.

Plugged Or Contaminated.
Using the wrong sort of fuel in your car causes plugged or contaminated catalytic converters. Using leaded or lead replacement fuel will plug up the monolith and cause it to stop working. A similar thing will happen if fuel additives are used that are not suitable for use with a catalytic converter.

Oil Fouled
This is caused by oil getting into the exhaust system and contaminating the catalytic converter. The most likely cause is a leaking gasket.

Melted/Broken Substrate
A monolith is usually broken when an object or when it suffers a sudden change in temperature impacts it. If the cat suffers road damage the monolith inside can be cracked due to it being crushed by the movement of the steel can.

The use of exhaust paste before the cat can also cause the monolith to break. When the exhaust paste has hardened small pellets can break away and shoot into the cat. The monolith will gradually be destroyed by these pellets and break down. The cat can also be destroyed by excessive engine vibration.

The monolith can be melted when unburned fuel is injected into the cat. This can be caused by the car being tow or bump started, or if the car’s engine requires several turns before firing. More information on the causes of melting monoliths can be found in the section on “Overheating”.

Overheating
There are many problems that can cause a cat to overheat or fail. The most common cause is unburned fuel entering the cat. Also faulty spark plugs and leads will cause the engine to misfire and ruin the converter. The cat will also be ruined if the distributor timing is out.

Oxygen Sensor
An oxygen sensor collects and sends information to the Electronic Control Unit. This is used to control the air/fuel mix. If the oxygen sensor is faulty, or it has been contaminated with silicone from anti-freeze or sealant, the air/fuel mixture will not be corrected and excess fuel will enter the cat, causing it to overheat.

Fuel Injection Systems
If a fuel injector is leaking internally or dribbling fuel into the engine the converter may be damaged. The excess fuel will enter the exhaust system and cause the cat to overheat. Due to the varying fuel injector systems the proper manual should always be consulted when trying to diagnose a problem.

Map Sensors
Map Sensors tell the Electronic Control Unit the load on the engine and the amount of air entering it. If this sensor fails it causes a rich condition in the engine, which can overheat the cat and cause it to fail.

Carburetor Systems
A worn or defective carburetor can cause a cat to overheat. Problems such as improper float or air/fuel mix adjustments and worn metering rods can damage the cat. The choke system also needs to be operating properly so the right level of fuel enters the system. If too much fuel enters the system the cat will overheat and eventually fail.

Canister Purge Valve Control
This vacuum operated valve vents fuel vapor from the carburetor bowl to the charcoal canister. If the vacuum is breached the charcoal canister will flood, causing the air/fuel mixture to become very rich. This will cause the converter to overheat and eventually fail.

Noise
A cat should not be considered to be a silencer although it does have some silencing qualities. Noise can be caused by excessive fuel getting into the converter

None of the described faults are covered by the guarantee.

Question

How do I know when the catalytic converter on my vehicle needs to be replaced?

Answer

The best way to determine if the catalytic converter has failed is by testing the exhaust with testing procedures like those used in state and local inspection programs. However, the following symptoms may also indicate a need for converter replacement: Broken or rusted out converter body or end tubes. Bits of substrate in other sections of the exhaust system. No rattle in a palletized converter (If the converter doesn't rattle, the pellets may have melted together or fallen out. A rattle in a monolithic converter (A rattle in this kind of converter indicates the substrate has separated.)

Question

My Technician was talking about the OBDII on my vehicle. What is that?

Answer

OBDII references the second generation of On Board Diagnostic used initially in California and now in all 50 states. It is a computerized engine and emission monitoring system designed to alert the driver that emission control service is needed.

Question

What is the connection between OBD and Vehicle emissions?

Answer

The vehicle computer will detect a system problem before the driver notices a drivability problem. OBD can also detect problems that might be noticed by visual inspection because they can be electrical or even chemical in nature. By detecting these emissions-related failures and alerting the driver to the need for potential repair, EPA hopes that vehicles will be properly repaired before emissions become a problem.

Question

How does OBD inform drivers of problems?

Answer

When the OBD system determines that a problem exists, a corresponding "Diagnostic Trouble Code" is stored in the computer's memory. The computer also illuminates a dashboard light indicating "Service engine Soon" or "Check Engine" or displays an engine symbol. This light, usually yellow in color, serves to inform the driver that a problem has been detected and vehicle service is needed. When the vehicle is delivered to the repair shop, a technician can retrieve the stored diagnostic trouble codes from the computer memory of the vehicle. It is important to note that an illuminated dashboard light, as described here, is intended to inform the driver of the need for service, NOT of the need to stop the vehicle. However, service should be sought as soon as possible. Drivers may also wish to consult a repair shop or their vehicle owner's manual for further guidance.

Question

Why does the dashboard light blink or flash?

Answer

Under certain conditions, the dashboard light will blink or flash. This indicates a rather severe level of engine misfire. When this occurs, the driver should reduce speed and seek service as soon as possible. Sever engine misfire over only a short period of time can seriously damage emission control system components, especially the catalytic converter, which is typically the most expensive to replace. Drivers should also consult their vehicle owner's manual for manufacturer specific instructions.

Question

How can the dashboard light be turned off?

Answer

After fixing the problem, the service technician will reset the fault codes, turning off the dashboard light. The vehicle's OBD system can turn off the dashboard light automatically if the conditions that caused a problem are no longer present. For example, if the gas cap is not properly tightened after refueling, the OBD system can detect the vapor leak that exists. If the gas cap is tightened, the dashboard light should be extinguished within a few drives.

Question

How does OBD help the environment?

Answer

The intent of OBD systems is to assure proper emission system operation of all vehicles over its lifetime by monitoring emission related components and systems for malfunction and/or deterioration. An important aspect of OBD is its ability to notify the driver of a problem before the vehicle's emissions have increased significantly. If the vehicle is taken to a repair shop in a timely fashion, it can be repaired before any significant emission increase occurs.

Question

How does OBD help consumers?

Answer

OBD systems are designed to alert drivers when something in the emission control system begins to deteriorate or fails. Early diagnosis followed by timely repair can often prevent more costly repairs on both emission control systems and other vehicle systems that may affect vehicle performance such as fuel economy. For example: a poorly performing spark plug can cause the engine to misfire, a condition sometimes unnoticed by the driver. The engine misfire can, in turn, quickly degrade the performance of the catalytic converter. With an OBD detection of the engine misfire, the driver would be faced with a relatively inexpensive spark plug repair. However, without OBD detection, the driver could be faced with an expensive catalytic converter repair in addition to the spark plug repair. OBD systems also provide far more information than ever before to help auto technicians properly diagnose and repair vehicles during periodic maintenance, or their first visit to the repair shop, saving time and money for consumers.