What to Do If the Vehicle Fails the Emission Test?

[Teddy]

While waiting for the emission test, keep the vehicle idling. Before the emission test, rev the engine a couple of times. For older vehicle models or engines with high mileage, you can add two bottles of fuel additive in advance to dissolve engine carbon deposits, or use higher octane gasoline to better suit the engine. During maintenance, you can perform cleaning of throttle carbon deposits, cylinder carbon deposits, fuel injector carbon deposits, and intake manifold carbon deposits. Backflush or replace the catalytic converter.

[Josephine]

Oh no, failing the emissions test is really frustrating. I ran into the same issue last time. Most of the time, it's because the catalytic converter is broken or there's too much carbon buildup. Don't panic yet—you can first check if your car has any abnormal noises or black smoke coming from the exhaust pipe. Then, it's best to visit a repair shop and have them use professional equipment to test the oxygen sensor and fuel injectors. If it's just a carbon buildup issue, a simple cleaning will do the trick, costing just a few dozen bucks. But if the catalytic converter is damaged, you'll need to replace it, which could range from a few hundred to over a thousand. To prevent this, avoid idling for too long, use higher-quality gasoline, and stick to regular maintenance. Remember, don't cut corners by going to shady shops—only certified inspection centers can truly solve the problem. Safety first—driving a car with excessive emissions is a no-go.

[AngelinaLynn]

Haha, my friend just went through this last month, and it really stressed him out. Generally, if the exhaust fails the test, the most common causes are a deteriorating catalytic converter or incomplete combustion in the engine. My suggestion is to first try switching to a different gas station—sometimes poor fuel quality can cause combustion issues. Then, take it to a professional repair shop to check the oxygen sensor and air-fuel ratio, and clean the throttle body and fuel injectors. Cost-wise, a simple cleaning might run you around a hundred yuan, while replacing the catalytic converter would be more expensive. When driving normally, avoid prolonged low-speed operation and occasionally take the car on the highway to rev the engine, which helps reduce carbon buildup. Oh, and some cities offer exhaust repair services—consider consulting them before rushing to replace parts. Make sure everything’s fixed properly before the re-inspection to avoid multiple trips.

[OJosiah]

If you fail the emissions test, it's mostly due to a faulty catalytic converter or fuel injection system. Once this thing breaks, emissions exceed the standard. At the repair shop, the mechanic usually checks if the catalytic converter is clogged or damaged, and whether the oxygen sensor is malfunctioning. Cleaning the fuel injectors or replacing the catalytic converter can solve the problem. It's not cheap—a new catalytic converter might cost a few hundred bucks. Regular maintenance with high-quality engine oil and avoiding prolonged idling can delay aging. If you can't pass the inspection, don't force it—fix the issue first and then retest for safety.