I. Method of judging damage

1. Appearance inspection

Check whether the catalytic converter is damaged or overheated during driving. After raising the vehicle, observe whether the catalytic converter has dents.  If there are obvious dents and scratches, it indicates that the carrier of the catalytic converter may be damaged.

2. Back pressure test

Make a hole at the appropriate position of the exhaust pipe in front of the catalytic converter, connect a pressure gauge, start the engine, and measure the exhaust backpressure at idle speed and 2500r/min. If the exhaust backpressure does not exceed the limit specified by the engine, it indicates that the catalyst carrier is not blocked.

II.  Causes of early failure

1. Too high temperature

The three-way catalytic converter does not have catalytic ability at room temperature, and its catalyst must be heated to a certain temperature to have oxidation or reduction ability.  However, when the operating temperature exceeds 850-1000°C, the catalyst on the inner coating may fall off and the carrier may break down.

2. Chronic poisoning

Catalysts are very sensitive to sulfur, lead, phosphorus, zinc and other elements.  Sulfur and lead come from gasoline, phosphorus and zinc come from lubricating oil.  These four substances and their oxides formed after combustion in the engine are easily adsorbed on the surface of the catalyst, preventing the catalyst from coming into contact with the exhaust gas and thus losing its catalytic effect, which is known as "poisoning".

3. Surface carbon

When the car is working at low temperatures for a long time, the three-way catalyst cannot start, and the carbon smoke emitted by the engine will adhere to the surface of the catalyst, causing it to be unable to come into contact with CO and HC.  Over time, the pores of the carrier will be blocked, affecting its conversion efficiency.