Clogged catalyst: symptoms, signs, main causes and recommendations

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:42

Catalytic reduction systems are used to reduce the amount of harmful substances emitted into the atmosphere from the exhaust pipe of a car. However, converters work as long as the catalytic element is in good condition. Over time, it stops working effectively. Let's take a closer look at what a catalyst is, its malfunctions, and solutions. It is also important for diagnosis to know the signs when the catalyst is clogged, the symptoms of the problem.

Catalytic converter - what is it and why?

On modern cars, it is one of the most important components of the exhaust system. The device cleans exhaust gases from harmful substances. These are nitric oxide, carbon monoxide, various groups of hydrocarbons. Inside the catalyst are special filters in the form of honeycombs.

They are made from precious metals. It can be iridium or platinum. It is thanks to these metal honeycombs that harmful substances are neutralized. There are three main elements in the design of the device - a metal casing, a carrier unit with honeycombs and a thermal insulation layer. The main element is the block carrier. Its design is based on refractory ceramic material. The composition includes a huge number of cells similar to honeycombs. They are designed to increase the zone of contact with gases. The honeycomb is coated with an alloy of platinum and iridium. Chemical reactions that take place during the interaction of exhaust gases with a layer of platinum-iridium alloy lead to a strong heating of the catalyst. As a result, all harmful unburned substances burn instantly when touching the metal surface of the honeycombs. The combustion process uses oxygen that remains in the exhaust gases after leaving the combustion chamber. Further, completely harmless substances exit the exhaust system from the catalyst - N₂ and CO_2..

Substances used in the catalyst and their functions

Catalytic converters use several substances. These are rhodium, platinum, palladium, iridium. The first element is a reductive catalyst. Its task is to restore NO and convert it into the most ordinary nitrogen.

Platinum and palladium serve as oxidizers. They should stimulate the acceleration of the oxidation of unburned hydrocarbons, and thenconvert them to steam. CO turns into carbon dioxide.

Signs and symptoms of a clogged element

If the catalytic converter is clogged, the symptoms will help determine it. Naturally, such symptoms can also indicate other malfunctions. But with a more detailed diagnosis, everything speaks precisely of the catalyst. If the element is completely clogged, the engine will start, but immediately stall after that. The car accelerates worse. When the driver presses the accelerator pedal, there may be a feeling that the car is holding something on the rear bumper. This indicates the presence of a blockage inside the converter. How else can you find out that the catalytic converter is clogged? Symptoms include increased fuel consumption. But this can only be taken into account when the car has lost power and responsiveness to the accelerator pedal. That is, the car stopped driving, and the consumption increased significantly. Also, when starting a cold engine, a pungent and unpleasant odor may appear.

Check Engine

This is a universal symptom, so you first need to know the error code that the system issued. The decoding of these codes is in the instructions for the car. But it should be borne in mind that such a lamp will light up only if two lambda probes are installed in the car's exhaust system. The first is usually located before the converter. It is designed to adjust the amount of fuel supplied to the engine.

The second sensor is needed to control the operation of the converter. It is this lambda probe that will give an error. For example,if there are all the above symptoms of a clogged catalyst on the Ford Focus-2, and the ECU gives an error P0420, then this indicates problems with the converter. The error means low gas removal efficiency.

Features of clogged elements on various cars

Let's consider different cars that are equipped with catalytic converters in order to diagnose the breakdown more accurately. It's worth starting with domestic models from AvtoVAZ. This is VAZ-2110, -2114, Kalina. In addition to the fact that the car will slowly accelerate, there are other signs and malfunctions of a clogged catalyst. So, there is a sound that appears from under the car. There is a feeling that crushed stone was poured into the converter housing. This sound is a signal indicating the mechanical destruction of the ceramic base.

If we talk about imported cars, then Ford Focus has identical symptoms of a clogged catalyst. VAZ-21124 is also equipped with such a cleaning element. If we talk about the domestic "dvenashka", then there is exactly the same decrease in power and noise inside the element. In general, clogging or melting of catalysts can be very difficult to detect and determine. All these signs also indicate problems with sensors, malfunctions in the power system, and ignition failures. Note that malfunctions in the last two systems are the reason why the catalyst is clogged. The symptoms confirm this. If the car is refueled with low-quality fuel, the fuel mixture is preparednot properly. If there are misfires, the mixture does not burn completely in the combustion chambers. Because of this, the exhaust gases contain a large amount of soot.

She is the reason why you have to change these nodes often. The cells in the catalyst quickly clog and melt.

Causes of failure

The node serves more than 200 thousand km. But in Russian conditions, this period is reduced. Catalysts fail due to poor fuel quality, high oil consumption, incorrectly tuned ignition system, mechanical damage.

How to diagnose?

Let's see how to determine if the catalytic converter is clogged. The methods are available to everyone and do not require special skills and knowledge. You need to start the car and pick up the engine speed to its maximum. Also, the engine is twisted at low, medium and high frequencies. In each of the modes, the pedal is sharply pressed to the floor. The motor should not fail, but, on the contrary, react sharply. If there is a weak response or the engine does not want to spin up to more than 5000 rpm, you should think about replacing the converter. Here's another way to check the catalytic converter. Signs and symptoms are confirmed, and it's time to make sure the element is broken. To diagnose, put a hand on the exhaust pipe. Exhaust gases move in pulses. You can accurately feel with your hand how they are pushed out of each cylinder in turn. If at idle the flow is even and constant, this directly indicates a cloggedneutralizer. If you press the trigger, and then turn off the engine, they will come out slowly. These are the gases that have accumulated due to a clogged catalyst.

Conclusion

So, we found out by what symptoms you can determine the malfunction. In order for the catalyst to work properly, experts recommend filling the car with only high-quality fuel and diagnosing all systems in the car in a timely manner.