Few things are more frustrating than your car, truck, or SUV failing the Oregon DEQ inspection. If it does, don’t worry. Accurate Auto is DEQ inspection specialists and we can fix the problem that returned the emissions failure. Why did your vehicle fail the test in the first place? Here are seven possibilities.
Out-of-Spec Fuel Metering
If either your fuel injection unit or computerized engine control carburetor is having trouble, your fuel metering will be off. This can cause your automobile to fail the emissions test. An adjustment might solve the issue or we may have to replace the part.
Oxygen Sensor Failure
The oxygen sensor senses how oxygen-rich your exhaust is and a failing unit will cause your vehicle to fail the emissions test. Additional troubles caused by a failing oxygen sensor include acceleration power loss and overheating.
Ignition System Defects
Specifically, your spark plugs, spark plug wires, distributor cap, or advanced ignition timer can cause the ignition system defect that results in an F on your emissions test. If any of these parts fail, they can produce high hydrocarbons, which are tested during the DEQ check.
If your vehicle’s MAP sensor is faulty, the result is engine vacuum leaks from gaskets or lines. The vacuum leak will show up during the emissions test and your vehicle will fail if there is an issue with the MAP sensor when it measures the combustion engine load.
Unbalanced Fuel Mixture
Your vehicle needs an air/fuel mixture to start and run. If the mixture is too rich in fuel, the emissions test will see higher CO2 levels, i.e. too much carbon monoxide. Usually, adjusting the carburetor will fix the air/fuel mixture, but the problem might also lie in the fuel injectors.
Air-Injection System Malfunction
Your vehicle’s air-injection system reduces carbon monoxide and hydrocarbon emissions. If this system is faulty, it will not control the carbon monoxide and/or hydrocarbon emissions, pushing too much out in the exhaust. This is a sure-fire fail of the emissions test.
Finally, EVAP is short for Evaporative Emission Control System, and this system makes certain fuel vapors stay put and are not released into the environment via vehicle exhaust. If your gas cap isn’t sealed, for example, gasoline vapors will seep out.