Why is he shooting at the silencer? Reasons and their solution

Loud pops from the muffler - the sound is not pleasant. They can often be heard on busy highways and intersections. The source of these sounds are mainly old wrecks, the place of which, it would seem, should have been in a landfill or in a museum for a long time. But such a misfortune does not bypass fresh cars. Even a small car recently bought in the salon can deafen the yard with loud explosions when you try to start it.

Why do pops happen?

The reason is quite simple: the fuel residues that have not burned out in the combustion chambers, together with the exhaust gases, enter the exhaust manifold and further through the muffler system, where, under the influence of high temperatures, they begin to explode.

Most often shoots at the silencer in the following situations:

• when starting the engine;
• during a decrease in speed, when the driver takes his foot off the gas pedal;
• when accelerating.

How dangerous is this situation? Let's just say that in terms of the level of damage caused, it is unlikely to be compared with the water hammer, which we wrote about recently on Vodi.su. The exhaust does not contain enough air/fuel mixture to cause critical damage to the engine and resonator. Nevertheless, at the moment of explosion, the volume of gas increases sharply and the pressure on the walls increases. Accordingly, if this is an old car with a rusted muffler somehow screwed on, then the consequences can be serious: burning through the walls, breaking the connections between the banks, tearing off the pipe, etc.

Common Causes of Muffler Explosions 

To accurately determine the cause, you need to find out exactly at what moments and under what conditions pops are heard. There can be many reasons. We will try to list the main ones.

The most obvious reason is low-quality fuel or gasoline with a lower or higher octane rating. Fortunately, modern engines with ECUs are smart enough and can independently adjust to the octane number of gasoline. But carburetor engines do not have such skills. And, as you know, the higher the octane number, the higher its resistance to self-ignition. So, if you pour, for example, A-98 into an engine designed for A-92, then one of the consequences may be shots into the silencer.

Other common reasons include the following.

Ignition timing not adjusted. In older cars, this angle is manually adjusted. In newer models, the ECU programs are responsible for the adjustment. As a result, the spark is delayed by microscopic fractions of a second and the fuel does not have time to completely burn out. In this case, such a phenomenon can be observed when the engine troit.

There are ways to independently set the ignition timing. We will not dwell on them, since the topic is rather complicated. But if the problem is ignored, then over time the walls of the exhaust manifold and muffler will burn out.

Weak spark. Candles become covered with soot over time, they can also get wet due to a weak spark. A weak discharge leads to the same consequences that we described above - the mixture does not burn out and its residues enter the collector, where they safely detonate, gradually destroying the engine and exhaust system.

There is only one way to deal with this problem - check the candles and replace them, go to the service station, where specialists will diagnose and determine the real causes of the breakdown. For example, due to a drop in compression in the cylinders, part of the fuel-air mixture does not completely burn out.

Well, it happens when motorists confuse high voltage wires when replacing spark plugs. They are connected according to a special algorithm. If, immediately after starting the engine, pops are heard, then one of the candles does not give a spark.

Reducing the thermal gap. When adjusting the valves, it must be taken into account that the heated metal parts expand, however, a small gap should remain between the camshaft pushers and the valves even in the heated state. If it has decreased, then part of the mixture on the compression stroke will be thrown into the manifold.

The valve timing is violated. This problem is more relevant for carburetor engines. As we wrote earlier on Vodi.su, the rotation of the camshaft and crankshaft must match. The camshaft is responsible for raising and lowering the valves. If they do not match, the valves may rise before the mixture is supplied, and so on.

One of the causes of phase failure is a stretched timing belt. As a rule, problems of this nature are noticeable when shifting gears to higher ones, when increasing speed and increasing engine speed.

Conclusions

As you can see, the problem of shots into a silencer is complex. That is, it cannot be said that this is due to the breakdown of any one unit or part. Neglecting such detonations will lead to more serious problems over time, so the first time you detect such explosions, go for diagnostics.

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