5 Reasons for Failing an Emissions Test
Emissions are the exhaust gases that come out of your car’s engine. Many states require vehicles to have emissions tests every six months to make sure they aren’t producing too much carbon monoxide. They also look for dangerous pollutants that may be in the gases.
If you find that your engine has failed an emissions test, you shouldn’t register your vehicle until you fix the problem, which is the problem that causes your car to emit high emissions.
5 Most Common Reasons for Failing Emissions Tests
There are many reasons why a car may have high emissions and fail an emissions test. Most causes are not very costly to fix. In many countries, you cannot legally drive a vehicle without passing an emissions test, so it is essential to address these issues. Below are 5 common reasons for high emission levels that cause a test to fail.
1) Fuel Injection Issues
The engine control unit controls the fuel injectors that are responsible for injecting fuel into the combustion chamber.
If either the engine control module or the fuel injectors fail, causing an air-fuel imbalance, more emissions will be released.
2) Faulty Mass Air Flow Sensor
The engine control unit uses the mass air flow sensor to calculate the mass rate of air entering the internal combustion engine. Once the engine control unit has this information, it knows how much fuel to put into the engine.
If this mass air flow sensor does not function properly, it can cause excessive fuel burning. This is called a rich fuel mixture, which produces excessive amounts of carbon monoxide.
3) Faulty EVAP system
The EVAP system is the evaporative emission control system found in most modern cars. Their job is to prevent gasoline fumes from getting into the atmosphere. Parts in this system include the vent, vacuum hoses, and gas cap. If the cap comes loose or the hose breaks, these fumes can escape and cause big problems.
4) Faulty MAP Sensor
The intake manifold pressure sensor, also known as the MAP sensor, provides data to the engine control unit about the intake manifold pressure. If there is a leak in either the vacuum line or the seal, a faulty MAP sensor could be the culprit. This will result in excessive exhaust gases from the engine.
5) Faulty oxygen sensor
This sensor inspects the exhaust gases and measures the amount of oxygen they contain. A faulty sensor can lead to increased toxicity of the exhaust gases and overheating of the engine.
Here’s how to identify these problems
The above problems may affect your driving, but this is easy to spot. For example, a faulty oxygen sensor can cause poor acceleration performance when you press the gas pedal.
Otherwise, you won’t really know if your vehicle is producing high emissions until you take it in for an emissions test every six months. If you live in a state that doesn’t require emissions testing, like Florida, you won’t know until you take your car in for an inspection or diagnostic test.
That’s why it’s important to know the main causes of high emissions so that you can prepare to perform a diagnostic test yourself and pass the emissions test in advance.