What to Do If the CO Emission Test Fails?

[StellaAnn]

Based on the emission test results, perform the following repairs: 1. Slight exceedance of CO, HC, and NO: Possible causes include excessive spark plug gap, poor fuel injector atomization, significant carbon deposits and sludge in the cylinder, or failure of the catalytic converter and oxygen sensor. Check the air filter, spark plugs, intake air temperature sensor, and intake manifold pressure sensor. Add dual-core anti-wear repair agent and high-efficiency cleaner. If ineffective, use a catalytic converter cleaner to clean the catalytic converter. 2. CO and HC fail, NO passes: Possible causes include insufficient oxygen supply in the intake system, cylinder wear, carbon deposits in the cylinder, poor fuel injector atomization, or cylinder wear and carbon deposits. Install an energy-saving purification chip device, use a high-efficiency cleaner, and add a dual-core anti-wear repair agent. 3. Slight exceedance of CO and HC, severe exceedance of NO: Possible causes include overly lean air-fuel mixture, significant carbon deposits in the intake system and engine combustion chamber, multiple ignition points in the cylinder, or failure of the catalytic converter and oxygen sensor. After using a high-efficiency cleaner, add a dual-core anti-wear repair agent and clean the catalytic converter with a catalytic converter cleaner. 4. CO exceeds limits, HC and NO pass: Possible causes include overly rich engine air-fuel mixture, incomplete combustion, blocked intake system, worn fuel injectors, or severe cylinder wear. Check the air filter, spark plugs, and ignition timing. After using a high-efficiency cleaner, add a dual-core anti-wear repair agent. 5. CO and HC fail, NO passes with black smoke under heavy load: Possible causes include severe cylinder wear and significant drop in cylinder pressure. If a self-repair protective agent cannot effectively increase cylinder pressure, replace piston rings, cylinder liners, cylinder gaskets, or cylinder heads. 6. Severe exceedance of HC, slight exceedance of NO, CO passes: Possible causes include severe carbon deposits in the cylinder, poor exhaust flow, aged spark plugs, or crankcase leakage. After using a high-efficiency cleaner, it is recommended to replace with high-quality engine oil and add a dual-core anti-wear repair agent.