What are the reasons for excessive vehicle exhaust emissions?
2 Answers
The reasons for excessive vehicle exhaust emissions are: 1. Engine misfiring; 2. Spark plug oil leakage; 3. Failure of the three-way catalytic converter; 4. Dirty intake system, exhaust system, or fuel system; 5. Faulty oxygen sensor; 6. Aging components, poor contact, or poor sealing; 7. Incomplete fuel combustion. The solutions for excessive vehicle exhaust emissions are: 1. Replace the engine; 2. Replace the spark plugs; 3. Replace the three-way catalytic converter; 4. Check the oxygen sensor; 5. Clean the intake system, exhaust system, and fuel system; 6. Add additives to the engine oil. Vehicle exhaust is an environmental pollution caused by the waste gases emitted by vehicles, and its pollutants include: carbon monoxide, hydrocarbons, nitrogen oxides, sulfur dioxide, lead compounds, and particulate matter.
I previously encountered older vehicles with excessive exhaust emissions, and found that many issues stem from the ignition system. Worn spark plugs and leaking high-voltage wires are the most common problems, as untimely ignition prevents complete fuel combustion. Another issue is incorrect air-fuel mixture ratios, caused by dirty mass airflow sensors or failed oxygen sensors, which can mislead the engine control unit into injecting too much fuel. Vehicles frequently used for short trips are prone to carbon buildup clogging the catalytic converter—when this gets blocked, harmful gases are directly emitted. Additionally, minor issues like a stuck crankcase ventilation valve or oil leaks in the turbocharger can lead to bigger problems. I recommend regularly reading fault codes and performing exhaust gas analysis, and paying extra attention to ignition components and sensor conditions for vehicles over 80,000 kilometers.
