What to Do If Your Vehicle Fails the Annual Exhaust Emission Test?
2 Answers
The following are some methods to help your vehicle pass the annual exhaust emission test: 1. Clean the throttle body: Generally, the throttle body should be cleaned every 20,000 kilometers. The cost at 4S shops varies significantly depending on the brand and model. 2. Remove carbon deposits inside the engine: Cleaning the internal carbon deposits involves using detergents to dissolve sludge, gum, moisture, and metal debris inside the engine, reducing contamination of new oil and extending the engine's lifespan. The cleaning interval is typically every 30,000 kilometers, and the method is quite straightforward. 3. Clean carbon deposits in the fuel system: This includes cleaning the fuel injectors, combustion chamber, spark plugs, and throttle valve. No disassembly is required; simply adding a specialized fuel system cleaner to the fuel tank periodically can achieve excellent results. 4. Clean carbon deposits in the intake system: While some carbon deposits are expelled through the engine, a portion can clog the catalytic converter, so cleaning should not be overdone.
I've been driving for over 20 years and have encountered failed emissions tests several times. The most common issues are clogged catalytic converters or faulty oxygen sensors causing excessive emissions. My approach is to first take the car to an open road and drive at high speed, revving above 3000 RPM to clear carbon deposits. Then I check the spark plugs and air filter, replacing them if they're worn out to avoid bigger expenses. Adding a bottle of fuel system cleaner to clean the fuel lines is worth trying. Taking the car to a repair shop for professional diagnostics and reading OBD trouble codes helps confirm the cause. Cleaning the fuel injectors and throttle body also proves effective. Preventive measures include using high-quality gasoline and avoiding prolonged idling. Failing emissions tests not only results in fines but also harms the environment, so it's best to fix the issue promptly. Generally, a few hundred dollars can solve the problem.
