February 1, 2010
Emission System
Pollution + Environment
The environment today is being constantly plagued with pollutants. The emission controllers on your customer’s vehicle could be damaging to the air we breathe, so check them out carefully and efficiently.
Vehicles today are very efficient and have different controls by which to curb emissions, but sometimes they break down. In some areas of Canada, there are operations in place to check the vehicle’s emission systems. For instance in Ontario, there is the Drive Clean program which uses ASM2525 Dyno Testing. Qualifi ed outlets perform vehicle emissions testing in order to verify the vehicle’s tailpipe emissions are within limits allowed.
 |
|
Seen here is an emission parts diagram of a Toyota system.
PHOTO: autodeadline.com
|
|
Catalytic converter
In essence, to be sure the catalytic converter is functioning to the best of its ability, it really should be replaced after about 150,000 km. This is an expensive piece of equipment and so should be checked over very carefully. You must follow the correct procedure to check the converter—use a heat detector to check the heat in front of the converter and at the back of it. The temperatures should be the same. If it’s quite warm at the front and cold at the back, the converter is starting to block up.
Some converters are heated and are more expensive because they change the gas into ‘water’ faster and therefore are much less of a polluter. In the winter, they take two to three minutes to warm up to their ‘less of a polluter’ state.
O2 sensor
The O2 sensor is another item that can harm the environment and after 150,000 km, this part should be replaced. Of course, it needs to be checked occasionally and for that you need a mini-voltmeter in order to check the voltage that the sensor is producing. It doesn’t take long to determine whether it’s good or not and should be sending out measurements that will tell you whether or not the O2 sensor is working. You must take great care when removing this item— it can break in the pipe. This becomes more costly for the customer. In fact, you should tell your customer up front that this is an intricate procedure and the sensor could break.
Wiring
The wiring is another part of the system that you need to check on. These wires are tiny and somewhat protected, but they get hard and tired after years of working, therefore not as reliable any more—and they really need to work perfectly. All items that have to do with the converter need to work flawlessly and in harmony.
Temperature sensor
Another very important item is the cooling system sensor—the temperature sensor of the engine. It works hand-in-hand with the emission control system. If the engine runs too cold, it receives a wrong signal and the air fuel ratio can be wrong.
EGR system
The EGR system must also be in perfect working order. This system works in a high heat environment (exhaust gas) and the EGR valve burns after high mileage.
The evap system
You must also keep a close eye on the gas tank evap system. There’s a filter in that system that needs to be changed. There are also several evap sensors that must be checked as well. If the ‘check engine’ light comes on, it could be a vapour loss or leak. Seeing an evap trouble code P0440 is very common with older vehicles especially after 5-6 Canadian winters. At that stage of their life, they aren’t working as efficiently as they could and may need to be replaced. This can be an expensive repair as corroded and rusted parts do not like to be disturbed.
So, as you can see, the emission system on a vehicle is a very important piece of equipment that should work for the environment.
Pierre Bissonnette was the technical instructor for a major aftermarket manufacturer. He holds a teaching certificate in andragogy – which is the art and science of helping adults, whose general education has been cut short, in their learning process.
| 
Pierre Bissonnette