What to Do If the Vehicle Fails the Exhaust Emission Test?
2 Answers
The solutions for a vehicle failing the exhaust emission test are: 1. Perform a three-way catalytic converter cleaning maintenance on the engine, cleaning the three-way catalytic converter and oxygen sensor; 2. Replace the spark plugs, clean the distributor contacts and distributor rotor contacts, and adjust the ignition timing; 3. Clean the air filter, and replace it if it is too dirty; 4. Switch to 97-octane gasoline or 97-octane ethanol gasoline and take a high-speed drive; 5. Near the testing station, use a high-pressure pump at a car wash to add some water into the exhaust pipe, insert a filter screen into the muffler, or use a vehicle exhaust purifier by adding it to the fuel tank and idling for 20 minutes or driving 5 to 10 kilometers.
I just dealt with this issue last month, failing the emissions test can indeed be frustrating. Simply put, don’t panic—common problems are usually limited to a few culprits: A faulty catalytic converter is the most frequent offender; think of it as the car’s purifier—if it’s clogged or malfunctioning, emissions will definitely exceed limits. Oxygen sensor failures can also disrupt the air-fuel ratio, causing black smoke to puff from the exhaust. Checking the spark plugs is a must, as worn-out ones lead to incomplete combustion, which emissions tests easily flag. Also, inspect the air filter—if it’s dirty, the engine struggles to breathe, like trying to jog while wearing a mask. I recommend starting with an engine diagnostic, focusing on these areas. Don’t hesitate to replace faulty parts, and always use genuine components—post-repair retests usually pass. If all else fails, visit a specialized emissions repair shop—their expertise is invaluable.
