Reasons Why Cars Fail Emission Testing

Reasons Why Cars Fail Emission Testing

Emissions tests are important for vehicles. In most instances, if your car doesn’t pass this test, you will not be able to get license plates. You will also not be able to fully register a vehicle. Aside from the logistics of this issue, you’ll find that automobiles with emission problems don’t run well, and could very well break down at any given moment.

Before explaining further about why car fails emission testing, the fastest way to correct is to hook up a OBD2 scanner to the car and let it instantly show what specifically is the cause for failure.

To avoid having to deal with the headaches associated with breaking down, and dealing with costly repairs, consider the following breakdown. The following are some of the most common reasons why cars fail emissions testing. The more you know about this, the more you can search for a reliable mechanic to help you get moving forward with the right fix overall.

Fuel Meter Issues

Every car today has a fuel meter. It focuses on several different specifications, but it helps with figuring out how much gas you have in your tank, how it’s being used, and when to inject more for speed, and movement in general.

Modern vehicles have computers that control a lot of the aspects of the gas and fuel being utilized. When anything is awry within the computer, or even the fuel injection unit, you will find that emissions suffer.

These things have to be fixed in order to move forward, otherwise you will not be able to progress in the right manner.

Oxygen Sensor Problems

Every car has an oxygen sensor. That sense focuses on the exhaust system, and focuses on whether or not there are toxic elements being pushed out.

This can very well cause a serious problem with your engine. If the sensor is blown, or if there’s a malfunction within the computer of your car, you’ll find that overheating will be commonplace.

Overheating could lead to break down and could cause serious havoc on your overall momentum.

Higher toxicity is not a good thing, it’s going to cause loss of power straightway, and will eventually cease your acceleration. Fixing this is important, and testing emissions could highlight if there is a sensor problem overall.

Ignition Elements Are Out

Your ignition system is something that you don’t really think about, until it’s blown. When you go to turn your car on, if there is a sputter, a delay, or any sort of sound that is peculiar, you may need a helping hand.

You’ll find that a faulty wire, a spark plug that is out, or just about any small element could be causing this issue.

This of course will cause a test to fail because the hydrocarbons will be far too high. The ignition system will be to blame if that’s the case.

Vacuum System Leaks

Your car has a vacuum system in place, and it works great most of the time. However, there are gaskets that run through your car, and those can leak. If there’s a leak in the vacuum line, you’ll not only smell it, your test will fail off the charts.

This is something that doesn’t require a great deal of money to fix, but it is important overall. You will not want the odor or the issue to be prolonged, as it could very well cause further damage to your cars parts.

Fuel Problems

Often referred to as a rich fuel mixture problem, you’ll find that contamination could occur through many sensors that you have in place.

When you have a malfunction in the oxygen sensor, for instance, you’ll find that pressure goes off the charts and high levels of carbon monoxide will result. This can manifest in a weakened ignition ratio, and cause serious problems when trying to start and run your car over time.

A mechanic can fix this outright, and make sure that the proper levels of carbon monoxide are in fact stabilized.

Air Injection Issues

Another problem that you may run into is that of air injection. Fresh air can be forced into the engine, and that could cause malfunctions if not properly controlled.

The right levels can shift, and you could have a car that is emitting gases that are absolutely dangerous to breathe in. It’s imperative that if you smell anything, or you hear any sort of rush of air through your driving, that you get help.

A mechanic can fix air injection malfunctions, including fixing how levels of gases are being emitted, and where they are being pushed out. With the right balance, you can ensure that your vehicle is not left on the side of the road due to break down.

EVAP Faults

EVAP stands for evaporative emission control system, and this usually helps with gasoline vapors. It basically ensures that vapors from the gasoline tank aren’t getting into the atmosphere and your vehicle. If there’s any leak alongside the hoses of your car you could have a smell come out.

The smell will absolutely be noticeable, and you could end up breathing in toxic gases, as well as spill them out into the atmosphere. Emissions that force out this problem can be absolutely difficult to return, and fix, which is why it’s imperative to let a professional handle the change and fix here.

Older Vehicles

Cars that were made before 1995 and especially those that were made before 1981 have problems associated with emissions. It’s due in large part to a shift in the manufacturing process, as well as laws about emissions and more. These older cars require a bit of fine tuning to pass modern tests, and in some cases will need complete changes to how they run. If a car fails testing, don’t panic.

Many states require tune ups, and proof of spending money to fix the issues. Once that is done, waivers can be attained to allow you to drive on the road, albeit with a car that may not be up to par with the standards of today’s emissions.

The change in emissions testing is due in large part to help prevent ozone evaporation, and smog in general. Limiting the amount of pollution in the air is the main reason why testing is in place, and without proper car maintenance, a vehicle may not pass the modern tests.

Reasons Why Cars Fail Emission Testing
4.5 (90%) 4 votes

One Response to Reasons Why Cars Fail Emission Testing

  1. The most known and near certain causes of a failed emissions test is a: Rich air-fuel mixture. This may be due to flawed functioning injectors or a malfunctioning oxygen sensor, so please ensure these components work correctly before taking car for inspection. … Defects in the evaporative emission control system (EVAP).

Leave a reply

About Us

Total Car Diagnostics helps fellow home car owners, mechanics, technicians, garage shops, engineers, ECU programmers and auto repair centers — to significantly cut down on maintenance, repair costs, time, money, energy… and all other frustrating headaches involved with dealing with vehicles — by providing cost-effective advice, tools and recommendations.


facebook Total Car Diagnostics  LinkedIn Total Car Diagnostics  YouTube Total Car Diagnostics

Home | About Us | Contact | Terms of Service | Privacy Policy | Tuning Disclaimer | Affiliate Program | Shop

Address: PO Box 1315, Byron Bay, NSW, 2481, Australia. Support phone: (+61) 401 605 241

© Copyright 2019 by Total Car Diagnostics. All Rights Reserved.