Preparing for an emissions inspection
Q. Why Is My Car Being Tested?
Your car's engine, just like millions and millions of other car engines all over the world, can be a significant producer of three pollutants considered to be hazardous to your health:
- Hydrocarbons (HC), which occur when your car's combustion process isn't complete.
- Carbon Monoxide (CO), which develops when your car's air/fuel mixture doesn't have enough air in it.
- Oxides of Nitrogen (NOx), which reacts with sunlight to form smog.
Your car is tested to insure that it's continuing to run as clean as it was designed to, and if it isn't, to identify which pollutants are being produced in excessive amounts, and need to be brought under control by having your engine serviced.
Q. Are my car's emissions really a serious rroblem?
Consider these facts:
Motor vehicles are the single largest cause of carbon monoxide air pollution and ground-level ozone (smog) on this planet. In a typical city, cars and trucks cause up to 75% of the hydrocarbon emissions that cause smog and 90% of all carbon monoxide pollution. 30% of all cars that are 5 to 7 years old put out excessive emissions. 55% of all cars 7 or more years old exceed emission standards. Your car's emissions does make a difference, and it's a difference that will ultimately benefit you.
Q. How does my car control emissions?
Modern cars control emissions two ways. First, they're designed to burn gas more efficiently than ever before. This automatically reduces the amount of pollution the engine produces, since pollution is typically caused by inefficient combustion. Second, today's cars have special devices within them that are designed to reduce emissions output even further.
When your engine is running, sensors in and around it continually detect and analyze an amazing range of information - from engine load to the amount of oxygen in your exhaust, and much more.
The information these sensors transmit to your on-board computer tells the computer how to set and control performance components that include your car's fuel injectors or fuel pump relay, idle air and speed controls, catalytic converter and dozens more. These "sense-analyze-control" processes happen many times each second. Even a minor malfunction in a single component can ultimately increase your emissions significantly.
Q. Why does a car fail emissions testing?
Generally, there are two reasons why a car won't pass an emissions test.
A critical emissions control component, such as the catalytic converter or oxygen sensor may have malfunctioned or failed. This alone may be enough to raise emissions to unacceptable levels.
Much more commonly, however, a car fails emissions testing simply because it hasn't been properly maintained. The on-board computer's job is to keep the engine running as efficiently as possible for as long as possible. When the sensors detect a component or system that's wearing out or malfunctioning, the computer compensates for the problem by telling other related components to operate differently. If this process of compensation has been going on long enough, the car seems to be running fine but actually all the proper control settings have been altered enough to allow excessive emissions to occur.
Q. What can I do to prepare my car?
The single best (and easiest) way to pass an emissions test is to have regular tune-ups every year. A properly tuned vehicle should pass any emissions test easily every time.
If you haven't had your car serviced regularly, getting a thorough tune-up before you have it tested is still your best bet to get through an emissions test without problems.
Q. Do I need professional help to prepare?
Yes - and no. You can inspect your car's engine for obvious signs of potential or developing emissions problems. Some things to check for:
- Loose or cracked vacuum lines
- Loose or corroded electrical connections
- Rusted or corroded air intake and exhaust pipes
- Cracked or swollen spark plug wires
- Dirty or clogged filters
You cannot, however, perform many critical analyses or diagnoses without professional training and equipment. Only your service professional can read the signals traveling between the car's sensors, computer and control devices, retrieve and analyze "trouble codes" that your computer creates and stores, check critical system components such as the oxygen sensor, fuel injectors, EGR valve and others, and clean, recalibrate, repair or replace many of these components as needed.
Q. If the car needs new parts, what kind will it need?
Make sure your service professional installs a brand of emissions parts that meet or exceed the specifications established by your car's manufacturer. Many high-quality parts actually work better than the original that came with your car, because they include improvements to correct flaws or deficiencies which were built into the original part by the car maker.