1.Installation and disassembly of three-way catalytic converter (integral type):
(1) Jack up the car safely.
(2) After cooling the three-way catalytic converter, unscrew the four bolts and nuts that connect the exhaust pipe to the three-way catalytic converter.
(3) Remove the three-way catalytic converter and gasket.
(4) Replace the two new gaskets and place them on the front and rear exhaust pipes.
(5) Install a three-way catalytic converter and tighten the bolts and nuts with a tightening torque of 43 Nm.
2. Disassembly and assembly of preheated three-way catalytic converter (integral type):
(1) Disconnect the battery negative cable. Note that the disassembly must be performed after the ignition switch is switched to K position and the negative battery cable is disconnected for 90 seconds.
(2) Remove the front exhaust pipe:
1 Loosen the two bolts and disassemble the bracket.
2 Remove the 2 fastening bolts and 2 fastening nuts of the front exhaust pipe and the middle exhaust pipe.
3 Using a 14mm socket wrench, remove the three fastening nuts from the front exhaust pipe and the preheated three-way catalytic converter.
4 Remove the front exhaust pipe and gasket.
3. Remove the preheated three-way catalytic converter:
1 Check whether the preheated three-way catalytic converter is cooled.
2 Disconnect the oxygen sensor connector.
3 Remove bolts, nuts, and No. 1 exhaust manifold bracket.
4 Remove the bolts, nuts, and exhaust manifold bracket.
5 Remove 3 bolts, 2 nuts, preheated three-way catalytic converter, gasket, retainer and gasket.
6 Remove five bolts and two heat shields from the preheated three-way catalytic converter.
4. Reinstall the preheated three-way catalytic converter:
1 Install two heat shields on the new preheated three-way catalytic converter using 8 bolts.
2 Install new gaskets, retainers and gaskets on the preheated three-way catalytic converter.
3 Install the preheated three-way catalytic converter using 3 bolts and 2 new nuts with a tightening torque of 29 Nm.
4 Install the exhaust manifold bracket using bolts and nuts with a tightening torque of 42 Nm.
5 Install the No.1 exhaust manifold bracket using bolts and nuts with a tightening torque of 42N.m.
6 Connect the secondary oxygen sensor connector.
5. Reinstall the front exhaust pipe:
1 Replace the two new sealing gaskets on the left and right ends of the front exhaust pipe.
2Temporarily install 2 fastening bolts and 2 new fastening nuts for the front exhaust pipe and the middle exhaust pipe.
3 Use a 14m long socket wrench to tighten the front exhaust pipe and a new fastening nut for the preheated three-way catalytic converter. The tightening torque is 62N.m.
4 Tighten the two fastening bolts and the two fastening nuts of the front exhaust pipe and the middle exhaust pipe. The tightening torque is 56N.m.
5 Use 2 bolt mounting brackets.
1. Must ensure that the engine is not a problem, not burning oil, burning oil, must overhaul the engine;
2. Clean spark plug carbon deposit or replace spark plug, clean injector, air grid, throttle, oxygen sensor poisoning failure must replace the oxygen sensor, then the measured data is accurate;
3. It is best to use 97# gasoline during the vehicle examination in order to fully realize the effectiveness of the three-way catalytic converter;
4. Three-way catalytic converter light-off temperature of 230-300 degrees, just put on a new three-way catalytic converter, need to heat the car or run dozens of kilometers and then to the vehicle inspection, inspection is best not to turn off the fire, avoid cold inspection Or, as soon as a vehicle is loaded, the effect of the vehicle inspection is often inaccurate. At the same time, the owner is also required to spend unnecessary expenses.
5. The OBD catalytic converter must be checked before and after the failure of the light to detect poisoning failure, if it fails, it must be replaced.
Cause of Issue
1. The temperature is too high.
(1) The three-way catalytic converter at room temperature does not have the catalytic ability, and the catalyst must be heated to a certain temperature to have the ability to oxidize or reduce. Usually the catalytic converter's light-off temperature is 250-350°C, and the normal operating temperature is generally 400. -800°C.
(2) The catalytic converter will produce a large amount of self-volume, the higher the oxidation temperature, and when the temperature exceeds 1000°C, the catalyst of the inner coating will sinter and necrosis, and it is also prone to spontaneous combustion of the vehicle. .
(3) Therefore, it is necessary to pay attention to controlling various factors that cause the temperature of the exhaust gas to rise, such as too late ignition time or disordered firing order, or a broken fire. This will cause the unburned gas mixture to enter the catalytic reactor and cause the exhaust gas temperature to rise. High, affects the performance of the catalytic converter.
2. Chronic poisoning.
(1) The catalyst is very sensitive to elements such as sulfur, lead, phosphorus, and zinc. Sulfur and lead come from gasoline. Phosphorus and zinc come from lubricating oil. These four substances and their oxide particles formed in the engine are easily adsorbed. On the surface of the catalyst, the catalyst cannot be brought into contact with the exhaust gas, thus losing its catalytic effect, the so-called "poisoning" phenomenon.
3. Surface carbon.
(1) When the car is working at a low temperature for a long time, the three-way catalytic converter cannot start, and the soot discharged from the engine will adhere to the surface of the catalyst, resulting in inability to contact with CO and HC. In the long term, the pores of the carrier will be blocked, affecting Its conversion efficiency.
4. Exhaust gas deteriorates.
(1) Catalytic converters have certain limits on the conversion capacity of pollutants. Therefore, the original exhaust gas must be reduced to a minimum by in-vehicle purification technology.
(2) If the concentration and total amount of exhaust gas pollutant components are too large, such as the mixture gas is rich, it will affect the catalytic converter's catalytic conversion ability and reduce its conversion efficiency.
(3) In addition, since a large amount of HC and CO in the exhaust gas enter the catalytic reactor, an excessive oxidation reaction occurs in the exhaust gas. The large amount of heat generated in the oxidation reaction will cause the catalytic reactor to be overheated and be damaged.