What to Do If a Car Fails the Exhaust Emission Test?
2 Answers
Insufficient ignition energy from spark plugs fails to completely burn the air-fuel mixture, resulting in excessive HC content in the exhaust. Poor atomization of fuel injectors or an overly rich air-fuel mixture can also lead to excessively high pollutant levels in the exhaust, causing the vehicle to fail the test. Therefore, it is essential to clean the fuel injectors regularly. The advantages of high-octane gasoline are mainly reflected in "two highs and two lows": higher anti-knock performance and power output, along with lower harmful substances in gasoline and reduced exhaust pollution. Neglecting the maintenance of the three-way catalytic converter can lead to its blockage, reducing its ability to convert harmful gases and ultimately causing the vehicle to fail the exhaust emission standards.
A few days ago, my old car also failed the emissions test, so I hurried to my regular repair shop. The mechanic said the issue might be with the catalytic converter or oxygen sensor, as being too dirty or failing can cause excessive emissions. He first did a simple check, like seeing if the engine light was on, and then suggested cleaning the intake system and fuel lines to try—excessive carbon buildup causing incomplete fuel combustion often leads to this. The cleaning cost was around 300 yuan, not too expensive; if that didn’t work, parts would need replacing, which is costlier. Regular maintenance is crucial—I always change the air filter and oil on time and use higher-quality gasoline to prevent many issues. If you fail the test, don’t panic; find a reliable repair shop, fix it, and retest—it usually passes. Ignoring repairs will cause trouble and fines at the next inspection. Remember, safety first—don’t drive on highways recklessly.