On engines ZMZ-40522 and ZMZ-40524, a catalytic converter is installed in the exhaust gas system
In terms of design, the only difference between the collectors is that an additional oxygen sensor (diagnostic) is installed in the collector ZMZ-40524 at the outlet of the collector.
A little about the principle of operation of a catalytic converter
A catalytic converter is designed to reduce emissions of carbon monoxide, nitrogen oxides and unburned hydrocarbons.
Passing through the neutralizer cells, carbon monoxide is converted into low-toxic carbon dioxide, and nitrogen oxides are reduced to harmless nitrogen.
The degree of gas purification in a serviceable converter reaches 90-95%.
For the normal operation of the converter, the composition of the exhaust gases (in particular, the oxygen content in them) must be within strictly specified limits.
This function is performed by the electronic engine control unit - a controller that determines the amount of fuel supplied depending on the readings of the oxygen concentration sensor.
If lead compounds are present in the exhaust gases, the catalytic converter and the oxygen concentration sensor will quickly fail.
Therefore, the operation of a car on leaded gasoline is strictly prohibited, even for a short time.
Also, a faulty ignition system can become the cause of the catalytic converter failure.
When sparking is skipped, unburned fuel, getting into the converter, burns out and cokes the cells, which can lead to complete blockage of the exhaust system and stop (or severe loss of power) of the engine.
The controller has a function to protect the catalytic converter against misfires that can be detected in one or two cylinders at the same time.
The controller at the same time turns off the fuel supply to these cylinders, and the engine management system malfunction indicator located in the instrument cluster lights up in a flashing mode.
In this case, you must stop driving, stop the engine, try to find the cause and fix the problem.
If this fails, the vehicle must be towed to the nearest service station.
Mufflers and the collector are non-separable units; in case of failure, they must be replaced with new ones.
A metal-reinforced heat-resistant gasket is installed between the collector and the cylinder head (common for the collector and the intake pipe).
Removing the catalytic converter
We squeeze the lock of the oxygen concentration sensor wiring harness connector (if it is a ZMZ-40524 engine, on the ZMZ-40522 engine, the lambda probe is installed on the exhaust pipe).
Disconnecting the sensor wiring harness block
Remove the bolt securing the catalytic converter to the bracket
With two wrenches, unscrew the nuts of the two bolts securing the collector to the muffler and remove the bolts
Remove the converter from the muffler
Remove the sealing ring
While holding the bolts from turning, unscrew the nuts of the two bolts securing the catalytic converter to the exhaust pipe and remove the bolts.
Remove the converter from the exhaust pipe and remove the gasket
Remove the catalytic converter
Install the parts in reverse order.