It is safely possible to call the modern power unit of the car miracle of technical thought – thousands of various details and knots are its part. Such complexity is designed to improve characteristics of the engine, including its reliability. But in practice leaves a little differently, and the principle “than is more difficult system, that high probability to it misoperation or breakage” is quite appropriate here.
Especially it is necessary to distinguish the “firing” giving to the muffler from set of the symptoms demonstrating existence of certain problems. The most surprising is that the considerable percent of motorists knows about such “cannonade”, stykatsya repeatedly with this phenomenon, but practically knows nothing about it. We intend to clear situation and to tell why the motor shoots at the muffler who is guilty of it and whether this problem is critical.
The reasons of the shots of the engine giving to the muffler it is unambiguous to answer question what the reason as a result of which the engine shoots at the muffler consists in, the most competent and experienced expert will not undertake. Moreover, it is impossible to answer question in advance whether the behavior of the power unit inadmissible is such, or such cottons can be ignored. Therefore for a start we will afford small theoretical retreat which will allow to clear the origins of similar sounds (for the majority of cases). As a rule, loud cotton arises because the gas mixture which has come to cylinder has not managed to ignite and to burn down completely throughout one work cycle therefore this process finishes already in final path, and in this case the system of suppression of sounds is almost powerless. But it is the investigation, but not the reason. That is we authentically know that violation of combustion procedure of fuel takes place, but it is necessary to find out it, therefore it occurs, and is very rare, and cases of constant “cannonade” practically do not meet.
Let’s note that shots can occur on any car: petrol, diesel or using gas, carburetor or with the system of injector injection. Certainly, understanding of the principle of functioning of the motor and gear of formation of cottons can incline you to the fact that responsible for it is violation of phases of gas distribution. In certain cases such statement is really fair, but by no means not always. Sometimes the reason is what to guess it is independently almost unreal. So – we begin consideration with such cases.
The clogged airfilter Yes, this element which is responsible for purification of the air coming to combustion chamber can quite be responsible for the cottons which are distributed in the muffler on single turnover of operation of the motor. The matter is that directly the air filter really does not participate in formation of the correct proportion of gas mixture, but indirectly – very influences. As you have understood. If the airfilter is clogged, it is simply not able to provide delivery of necessary amount of air that as a result results in oxygen deficiency. In this case speak about the enriched mixture (as fuel turns out more, than air). And time so, manages to burn down only that amount of gasoline for which rather available oxygen (without it process of burning is impossible in principle). For this reason the certain part of fuel which is present at mixture flows down to the output highway. And as there, especially on initial sites, temperature condition extremely high, gasoline flares up already in the muffler therefore the notorious shot appears.
Preliminary treatment of such failure consists in check of condition of the airfilter and if it is strongly polluted, it should be replaced, without waiting for procedural terms. Thus, it is possible to call this reason unevident, but the simplest in respect of elimination. The disadjusted (incorrectly adjusted) carburetor For carburetor cars, especially age, is very often found reason of formation of cottons in the muffler, especially at gas release. Many young drivers at all never faced carburetor cars – they are not issued for a long time, but in Russia the park of these cars is still huge. And so, for ignorant it is explained that the carburetor is gear which main objective is preparation of TVS, and without participation of electronics. So here a lot of things the component and the correct control which is carried out manually depends on state its separate. If at the same time the inaccuracy which leads to formation of the enriched mixture is allowed, then the same situation which is characteristic of the clogged airfilter turns out – gasoline burns down not completely and gets to the muffler where safely and flares up with characteristic shot.
At such manifestations it is necessary to start resetting of the carburetor. In principle this business simple – for a start it is necessary to check gasoline level in float chamber. There is considerable quantity of designs of carburetors, even for identical models of different generations therefore also standard level at them is not identical. But it is possible to expose floater, and without knowing concrete features – it is obliged to be aflush with the top border of the camera. If the floater is not at this level – it is necessary to adjust the gear as appropriate (here too there can be nuances concerning resetting mode). Violation of integrity of floater can also be the reason of his inadequate behavior because of hit in fuel and change (deterioration) of buoyancy. The polluted or incorrectly adjusted orifice plugs can be the reason that from the muffler cottons are distributed when pressing gas from time to time. If in such state there is air orifice plug, it is not able to provide giving in combustion chamber of necessary volume of air. The mixture as a result becomes enriched with the corresponding consequences. The problem too simply is solved: if the orifice plug is polluted – it is cleaned (wash with solvent, blow under pressure). If it is incorrectly adjusted – we take the screw-driver with flat tip and we twist orifice plug in the necessary party (by eye, with the subsequent check of results).
By simple tool methods to estimate quantitative structure of TVS prepared by the carburetor it is almost unreal so owners of old cars are forced to make resetting of the carburetor rather often. Problems in the ignition system One more common cause why the power unit shoots at exhaust pipe, incorrectly exposed ignition is. If the spark moves with lateness, chug-chugs will be distributed more often during the operation of the motor on XX and also at sharp pressing on accelerator pedal. In terms of mechanics of the processes happening in combustion chamber, such effect speaks as follows: the spark arises at the time of full opening of the inlet (giving) valve therefore even if mixture proportion ideal, manages to ignite only its part, other gets into collector (both gasoline, and air) so explosion will be inevitable and loud. If ignition is exposed towards advancing, then part of TVS will get to the return highway because of what cotton will be heard from the region of the air filter.
Is consequence of overdue giving of spark not only shots – during the long operation of the motor on delayed ignition the risk of burn-out of inlet valves is high that it is fraught with carrying out overhaul. So emergence of cottons because of the wrong operation of the gear of ignition of mixture demands immediate intervention. Modes of the correct resetting of ignition there is set, but the most exact of them can call method with application of stroboscopic light. Owing to limitation of volume of article we will miss the description of this process – it can easily be found in network for VAZ classics. The mixture can burn down not completely and at the correct giving of spark and normal proportion of air to fuel if spark insufficiently powerful. Such problem is characteristic of the following cases: high-voltage wires have poor contacts, insulation failures, korotit on weight – in all these cases on candle the charge of smaller force arrives, and the weak spark is able to ignite only part of TVS; there are problems in functioning of tramblyor. It also should be subjected to careful check; one of candles or at once have a little developed the resource – in such cases they will spark much more weakly too, than the associates who are in more privileged position; use of candles with ill-fitting characteristics (not the corresponding sizes of tip, the wrong heat rating). It also has significant effect on deterioration in process of sparking.
The thermal spacing which is not meeting standards understand the linear distance corresponding to increase in the sizes of certain knots of the power unit as a result of their heating As this term. Most often the thermal spacing is mentioned in context of cams of camshaft and valve pushers. If this spacing is exposed with violations – we will receive one more reason of the shots which are distributed from the muffler. Indirect symptom which can testify to misfit of thermal spacing in the engine towards its increase is the increased noisiness during its work which is followed by notable falling of power. On the contrary, at the umenshyonnykh the sizes of thermal spacing the main sign of failure just are also the cottons from exhaust pipe which are often arising idling. Reason here following: the valve is not able to close gleam completely, and fuel also gets into this crack, getting to collector and further to the final highway. The procedure of change of thermal spacing is known as resetting of valves. It is possible to carry out it and independently, it is simple, the main condition – the motor has to be completely cooled down. Usually at emergence of interruptions in operation of the power unit many drivers, irrespective of experience, start failure diagnostics, testing the motor during the work on all possible modes, and it is possible to call this tactics correct. If explosions of gasoline in the muffler arise on different modes of behavior of the motor, it demonstrates that, most likely, there is thermal spacing which is not meeting standards on GBT valves.
About need to prepare the tool (set of keys and probes) for resetting of valves will specify also emergence of shots from the muffler as a result of operation of the motor in the extreme thermal mode (in other words, when overheating). It is caused by the fact that pushers of camshaft are obliged to have sufficient TZ there. Where there is their contact piece to valve rod. The stronger the power unit heats up, the its details increase by bigger distance, as leads to reduction of this spacing. And if the valve collar is adjusted according to norms, then it adjoins nest most densely. The valve in case of lack of spacing will not be able to close gleam entirely, allowing mixture to get under the influence of pressure into the final highway and to flare up under the influence of high temperatures already there. So to be able to regulate the valve is duty of each owner of the car with the engine with carburetor, the benefit this procedure, though it is responsible, but it can be executed independently. Malfunctions in work of GRM If the gas distribution mechanism works not as it is necessary, consequences of it I will be shown by the symptoms almost indistinguishable from problems with operation of the ignition system. So, because of such failures the outlet valve begins to open before TVS burns down entirely, allowing part of mixture to get to collector, as becomes the reason of their explosion-like ignition in the muffler which is followed by instant distribution of sound wave. Let’s list the reasons leading to violations in work of GRM: belt wear/tension, shown emergence of additional noise and cottons with characteristic metal sounding which will occur during the operation of the motor on mainly low turns. The loosen belt should be tightened and if its state does not cause special trust – better not to risk and replace it with new. With the detailed procedure of replacement of GRM belt it is possible too will examine on our website; wear of cogged pulley. Here consequences are similar, and the problem is fixed by its replacement; loss of operability of valves. It can occur for various reasons. For example, because of emergence on their surface of deposit – usually it is result of use of fuel of doubtful quality. As a result the gear of gas distribution begins to fail. Leads the lag of valve springs which is followed by overheating of the motor to the same consequences. audit of valves allows to reveal similar problems. In case of detection on the plane of valves of signs of deformation (hillocks, roughnesses, deepenings), it is necessary to be engaged in their grinding in. But if defects are extensive and deep – grinding in will not help. In such cases carry out grinding work of valves, but their replacement on new will be more reliable mode of resuscitation of GRM.
Replacement of GRM belt As a rule, at emergence of the above described failures of GRM the engine shoots at the muffler, being in completely heated-up state. If on the cold power unit shots are absent – it is possible to say with high degree of confidence that the reason can consist in GRM. However it is better to make more careful preliminary treatment for specification of the diagnosis nevertheless. Why the injector car shoots Though on the frequency of occurrence of this problem carburetor vehicles are out of competition, chug-chugs – not rarity and concerning their injector fellows. But as gears of formation of mixture here absolutely others, and the reasons leading to shots the muffler will differ too. Here the on-board computer which is helped by numerous sensors steers preparation of the TVS components and in general operation of the power unit. So in principle they often are sources of problems with burning of fuel-air mixture. Failure or failures in operation of any sensor will lead to the fact that EBU will obtain partially distorted information and to make the wrong decisions on its basis.
Here the on-board computer which is helped by numerous sensors steers preparation of the TVS components and in general operation of the power unit. So in principle they often are sources of problems with burning of fuel-air mixture. Failure or failures in operation of any sensor will lead to the fact that EBU will obtain partially distorted information and to make the wrong decisions on its basis. It is possible to give operation of the sensor of intake of air as indicative example. If DZV works incorrectly, proportions of TVS will be far from ideal, and it will affect as deterioration in operation of the engine, and will be shown by characteristic cottons. The incorrect indications transferred to the on-board computer by the failing crankshaft position sensor will force EBU to perceive offset of KV on one cog or more as norm that too will affect operation of the motor. Misoperation of the sensor of Hall, DPDZ and some other sensors can lead to negative consequences. It is a little modes of check of their serviceability. One of the most available – installation of obviously efficient device, but it if is other driver ready to provide the sensor for your experiments. To buy new “for emergency” – the pleasure available not for all. Therefore it will be more correct to carry out computer preliminary treatment with use of the autoscanner and the special program allowing to interpret codes the given error messages. It is possible to define in such a way the problem sensor literally in only a few minutes. At the shots which are distributed from the muffler of injector car it makes sense to make at the same time CD and injector as it is also one of the main sources of emergence of problems with giving and ignition of mixture. Resetting of spacings of valves on car with the injector system of injection is made in the same way as on old cars with the carburetor. There can be problems and with distribution of phases. Anyway most precisely to define why the injector engine shoots, use of the autoscanner – the irreplaceable tool which substantially excludes influence of human factor with which all owners of carburetor cars are well familiar helps.
Other reasons We have considered the most characteristic failures leading to such phenomenon as the loud cottons which are distributed or from motor compartment (seldom) or their exhaust pipe. But there are also rather infrequently found reasons which also deserve that you knew about them. Let’s list them: the shots arising only during the operation of the motor idling arise for two various reasons – if ports of idle running are strongly polluted and if there was depressurization of intake manifold; cottons from the muffler – the ordinary phenomenon if to give preference to cheap low-quality fuel. The same problem is characteristic when filling the fuel tank with gasoline with smaller octane number, than it is recommended for this engine make. So the aspiration to save on fuel will halloo to you the whole lots of problems, unmuting frightening passersby; if you made cleaning of spark plugs, it is quite probable that at installation of wires you have made mistake. It occasionally happens even to skilled motorists. The problem with starting engine operation which quite often is followed by the shots giving to the muffler will be result of such oversight; in the presence on your car of economizer it is necessary to check its working capacity surely. It, undoubtedly, very useful adaptation helps to ensure optimum functioning of the power unit at the raised loadings, but its failures can be the main reason for emergence of shots; we did not mention also possible failures in work of air shutter, and it is obvious cause of infringement of proportions of preparation of TVS with corresponding too and it is good to us the known consequences. So also this element is subject to check and if necessary resetting;
if cottons behind are distributed mainly at the time of accelerator pedal otpuskaniye, the poor contact between exhaust manifold and “trousers” – initial part of the muffler is the possible reason of this phenomenon. It is simple to diagnose problem – in the presence of holes it will be and is heard, and is noticeable. To fix problem it can be problem if one of the butted parts has partially collapsed from overheating – in this case it is necessary to change all element; on injector cars the “leak” of spray jets arising owing to their productivity increased in relation to nominal indicators can be involved in shots from the muffler (more true. capacity). As a result of TVS it turns out enriched, does not manage to burn down in cylinders, being splashed out in exhaust manifold. Rather simple method of check of spray jets is known: it is necessary to carry out start of the motor at the highest turns of rotation of the crankshaft (having pressed on the accelerator pedal almost against the stop). It is called the mode of blowdown of spray jets, such procedure is recommended to be performed regularly, irrespective of existence or lack of the above-stated problems. If during this action shots are heard – it means that there are spray jets (at least one) which “flow”; the detonation sensor working with “glitches” can become too the reason of late ignition of mixture and what it threatens with, we already know. Can fail the sensor because of reaction to emergence in the engine of unwanted sounds. Check of its working capacity is carried out by means of carrying out CD; when shots from the muffler are distributed at gas release, it is very probable that the reason is in burning out of outlet valves. Most often loud sounds are formed at the moment during descent of the car from the mountain by the engaged drive (not on neytralka). Solution – audit of valves; the contact ignition system has one essential shortcoming – the spacing on its contact pieces has property over time to change in this or that party. There are problems with mixture firing point (delay or advanced ignition);
existence of leaky joints and holes in the system of offtake of exhausts – one more characteristic cause of the single shots which are distributed when dumping pedal of accelerator. The first layer pads between parts of the muffler (the resonator, “trousers”, final part of the muffler, the catalyst) suffer, in the second turn the tubes which are especially located close to the power unit burn through; at last, by responsible for the problem considered by us (and decelerations of power of the motor) reduction of gasoline pressure (as a result of problems with gasoline pump or blockage of branch pipes) and also drop of compression can be put (when cylinders lose former leakproofness). Check of ignition coil will be useful.
Preliminary treatment of the muffler of the car We have not mentioned about volume, loud sounds from the muffler can be on connected with ignition of fuel in exhaust path. They can arise because of availability of the condensate accumulating in tube early in the morning or at the increased air moisture. Hot gases, interacting with cold dew, can also lead to cotton. Not such intensive, but too to quite sonorous. If the car is equipped with the catalyst, then this quite ordinary phenomenon from which only harm – premature corrosion of the muffler. As we see, the reasons of cottons of the motor – fair quantity so if at you such cases have become frequent – considerable amount of works on clarification of the reason of the phenomenon is necessary. And it is necessary to begin with check of the exhaust system regarding its leakproofness. If here everything is all right it is possible to start preliminary treatment of knots of the engine, carburetor and other knots involved in hit of fuel in exhaust pipe. Cottons at the cars equipped with GBO As recently the increasing number of drivers for economy transfers the cars to liquefied gas, it is necessary to mention the reasons of shots and on such engines. As statistics shows, most often this problem is characteristic of GBO of the third generation installed on the injector motor. At the same time the place of dislocation of loud sounds is distributed approximately equally between inlet and final paths.
For GBO it is a little main reasons: supply of gas does not differ in stability because of the clogged airfilter or the wrong resetting of gas reducer; if the car is equipped with the injector system of injection, then the MRV sensor, failures in which operation lead to the wrong reaction of EBU that, in turn, leads to violations as a part of mixture, can be responsible for shots; incorrectly exposed ignition which is shown as well as in the case described above, cottons. At advanced ignition they will arise in the airfilter or intake manifold, at late – in exhaust path. It is necessary to watch closely condition of GBO more as many failures threaten with self-ignition of the engine.