car exhaust

The Essentials Of Car Emission Testing

Emissions Systems

I gotta admit it – there’s a fairly significant portion of my auto repair business that deals with regulations. Whether it’s national, state, or local, the government wants to make sure that your car is running clean and inline with guidelines laid out by the Environmental Protection Agency (EPA).

While clean air practices are enforced by the EPA they cannot enforce inspections of vehicles.

This is left to the hands of the state.

The state determines how often testings should be done and the requirements to past the emission testing. Some states only require smog and emission testing in some areas within their state.

What Is The Importance Of Emission Tests?

Through the emission test, the amount of pollution that a car produces will be revealed. The amount of pollution will vary but some factors can affect it.

Some older vehicles that are considered as antiques are exempted from the test because they were produced before manufacturers have access to more efficient car emission system parts. Similarly, some newer models are not required to take the test because they are made of the most efficient parts and a clean engine.

Due to the number of cars today, there is really a significant amount of pollution from the car’s exhaust. This is why the state continues to test cars for their emission. This pushes car owners to take the necessary steps to lessen the pollution they produce.

What States Requires Car Owners To Take The Emission Test?

The emission test is mostly done on urbanized areas. States that have vast rural lands may not require their residents to take their car for testing. This is especially true for those who are in areas with low population or In remote areas.

How Is The Car Emission Test Done?

The car’s interior and exterior will both be inspected if the car is up for a car emission test. Only qualified inspectors will be assigned to check the emission system visually and then functionally.

Functional testing will involve the check-engine light, ignition timing, the re-circulation system of gas, the evaporation system of the fuel until the gas cap. Next up is the On-Board Diagnostic system. Then they’ll finally measure the emission released by the tailpipe of the car.

A car that passes the emission test will receive a certificate. On the other hand, if the car doesn’t pass the test, it should be serviced or repaired so that it can meet the requirements created by the state.

The mechanic can run a diagnostic test to determine where the problem lies. You can also try to diagnose your car on your own using diagnostic tools but it would be best to consult professionals. Also, knowing how the car’s emission works can help with the diagnosis.

Causes Of Failed Emission Test

Failing the emission test can be stressful for the car owner. It means that the car needs to be serviced by a mechanic to try and fix the problem. There are different reasons why a car fails the emission test and the solutions also vary in price.

In general, the most common cause of a failed emission test is easy and not expensive to remedy. Here are the most common reasons why your car can fail an emission test:

Defective Ignition

A defective ignition can be detected by the analyzer due to the high levels of hydrocarbon. This is caused by worn-out spark plugs or the wires, improper ignition timing and a worn-out distributor cap.

Malfunctioning Oxygen Sensor

The amount of oxygen in the exhaust gas is measured by the oxygen sensor. It should always be checked to ensure that it can properly read the levels. If you continue to use the malfunctioning sensor, it leads not only to more toxic emissions but also overheating and inability to accelerate.

Faulty EVAP

The EVAP (Evaporative Emission Control System) makes sure that the gasoline vapor is trapped and doesn’t go into the air. A faulty EVAO is usually caused by leaks in the vents, valves, hoses or the gas caps.

Defective Air Injection System

To reduce the amount of carbon dioxide as well as hydrocarbons, the injector air system forces fresh air in the engine’s exhaust. If this system is faulty, the engine cannot lessen the number of hydrocarbons and carbon monoxide released in the exhaust.

Improper Fuel Mixture

When high levels of carbon monoxide are found in the exhaust, the car may be burning too much gasoline. This is a result of an improper air-fuel mixture due to a faulty oxygen sensor or a faulty fuel injection sensor.

Should I Get A Second Opinion On A Failed Emission Test

If a facility has already failed your car in the emission test, there is no use in getting another test without first fixing your car. The tests are reliable and the result of the second test are most likely the same as the first one.

A Sign Of Failure

When your check engine light is on, there is a great chance that you won’t pass the emission test. That light is a warning about the malfunctions happening on the emission controls of the car.

Terry Wade

Terry Wade is a traveling Car Mechanic in Southfield Michigan. He's been repairing cars for nearly 20 years.
Start Protecting Your Car Paint Today! Here’s How…
Outsmart Those Car Repair Scammer With These Tips

About Me

TerrysArticles is brought to you by ME!, traveling Mechanic Terry Wade, I’m do my darndest to update the site with the best quality articles and news available on the internet and elsewhere to help you diagnose and fix your vehicle yourself.

Thanks for stopping by!

T Wade - At the Shop
T Wade - At the Shop

Subscribe Now

Don't miss out on our exclusive monthly email series.