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Faults in the exhaust system

May 8, 2021

The exhaust system of a modern car is operated under severe conditions, which are determined by the high temperature of the exhaust gases, the impact of the external aggressive environment, the vulnerability of the structural elements. Therefore, malfunctions of the exhaust system occur from time to time. Sometimes you have to go to companies that deal with scrap removal in newmarket. According to the design, the following exhaust system malfunctions can be distinguished:

muffler malfunctions;
catalytic converter malfunction;
Malfunctions of the oxygen sensor.

Muffler malfunctions

The following muffler malfunctions are distinguished:

Damaged, corroded or burned-out muffler components;
Damage to the muffler’s suspension;
A weak connection of system components.

The main causes of muffler malfunctions are:

mechanical effects (collision with an obstacle);
External environmental influences (moisture, salt, condensate);
the limit of service life;
the use of low-quality components.
It is quite simple to determine the muffler malfunction, because its external manifestations are well distinguishable. Roar, splitting sounds, exhaust gas leakage indicate damage of muffler elements, as well as their unreliable connection. Rattling, muffled noises under the underside of the car accompany muffler suspension failure.
Catalytic converter malfunctions

The catalytic converter is a very delicate part of the exhaust system. Under normal operating conditions, the catalytic converter will last about 150,000 km. When deviating from the rules “death” can occur much faster. The catalytic converter malfunctions include:

melting, destruction or contamination of the carrier unit;
damage, corrosion of the catalyst body.

Melting of the carrier unit occurs when part of the fuel-air mixture burns in the catalytic converter instead of in the engine chambers. There are several reasons for this: ignition skips in the same system, fuel-air mixture enrichment and incomplete combustion when the oxygen sensor or other engine control system sensors are defective, or the vehicle is started by towing.

Destruction of the carrier unit can occur from mechanical impacts, as well as from a sudden change in temperature (e.g., driving into a puddle).

Causes of carrier unit contamination include:

Use of leaded gasoline (lead deposition on the cell surface);
Use of fuel with metal-containing additives (e.g., ferrocene);
combustion of oil during engine operation (coking of the honeycomb by products of oil combustion)

Neutralizer body failures occur for the same reasons as muffler failures.

On modern vehicles, the catalytic converter is monitored by a self-diagnostic system. Two oxygen sensors installed before and after the catalytic converter assist in this process. If deviations from normal operation (deviations in the sensor signals) are detected, the corresponding signal lamp on the instrument panel illuminates and a fault code is identified and stored in the memory of the electronic control unit.

Catalytic converter malfunctions create additional obstacles for the exhaust gases, which in turn affects engine performance: loss of power, erratic operation, impaired dynamics, and increased fuel consumption.

An indirect indication of catalytic converter malfunction can be a persistent systematic smell of hydrogen sulfide (“rotten eggs”) in the vehicle interior.

A defective catalytic converter cannot be repaired or repaired.

Faulty oxygen sensor

The oxygen sensor is the most vulnerable element of the exhaust system and the engine management system. One or both sensors may malfunction during operation for various reasons.

Faults of the oxygen sensor are:

heater failure;
Burnout, contamination of the ceramic tip;
oxidation, contact failure.

The causes of these faults are basically the same as with the catalytic converter: fuel quality, oil in the exhaust gases, ignition system malfunctions. The lambda probe can fail due to the service life limit (about 60-80 thousand km of mileage).

The oxygen sensor is also monitored by the self-diagnostic system. If a malfunction is detected, the signal lamp on the instrument panel lights up.

Indirect signs of sensor malfunction – unstable operation at low speeds, increased fuel consumption and low dynamics. It should be remembered that these external signs accompany the injection system and ignition system malfunctions.

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