Why doesn't it develop? What to do if the engine does not spin up? Easy Ways to Increase Engine Power

Reducing the number of engine revolutions significantly affects its power and traction. If suddenly your car has lost its former agility, you should think about diagnosing it, because such symptoms do not bode well.

In this article, we will talk about why the engine does not develop speed and what this may be due to. We will also consider the probable causes of loss of power by the power unit and methods for their elimination.

Symptoms

Determining that the engine does not develop the speed that it should develop is not difficult, especially if you have driven a car before and know its native characteristics. Those drivers who have encountered a similar problem in their practice know that a decrease in power is characterized by sluggish acceleration, loss of dynamics, traction, as well as engine overheating and increased fuel consumption. Sometimes these processes are accompanied by bluish or even black exhausts.

Are you pressing the accelerator pedal and the engine is not revving well? Pay attention to the tachometer. A serviceable motor should instantly respond to an increase in the amount of fuel supplied to the combustion chambers by increasing the number of rotations of the crankshaft. And if this does not happen, you need to urgently look for a malfunction.

Main reasons

There can be many reasons why the engine does not develop speed. Here is a list of the most common ones:

• the power unit is not warmed up to operating temperature;
• low or, conversely, excessive fuel level in the float chamber;
• the accelerator pump is faulty;
• clogging of jets, carburetor channels;
• air leak in the intake manifold;
• ignition timing incorrectly set;
• valve timing is broken;
• gaps of spark plugs are violated;
• clogged air or fuel filter;
• malfunction of mass air flow sensors, crankshaft position, throttle position, detonation;
• insufficient compression in the cylinders, etc.

As you can see, the list is quite voluminous, although it cannot be called complete. Let's consider in more detail the listed faults.

Cold engine

It would be wrong to demand full power from the power unit until its temperature reaches the operating temperature (90 0 C), especially when it comes to a carburetor injection engine. A cold engine does not rev to its full potential, even with the choke fully closed. The fuel mixture must be preheated before it enters the combustion chambers. Otherwise, the car will “twitch”, and the engine will stall and detonate. So, if your car is equipped with a carbureted engine, do not rush to leave until it warms up.

Fuel level in float chamber

The fuel level in the float chamber can also affect the operation of the power unit. If it is lower than it should be, the concentration of gasoline in the combustible mixture decreases. Because of this, the engine does not develop power. At an overestimated level, the mixture, on the contrary, is too enriched, but more than the norm enters the combustion chambers. Before entering the cylinders, it does not have time to warm up in the intake manifold, which leads to detonation and loss of speed.

The fuel level is adjusted by bending (bending) the float mounts.

Accelerator pump, channels and carburetor jets

Continuing the theme of the loss of power of the carburetor engine, one cannot fail to mention the accelerator pump. It is on its serviceability that the response of the power unit to pressing the accelerator pedal depends. Most often, the problem lies in the fuel supply, and the “spouts” of the sprayer are to blame for this, through which gasoline is supplied in a thin stream. To check the performance of the carburetor accelerator pump, you will need to remove the air filter so that a view of the first chamber opens. Next, you need to open and hold it for a few seconds. At the same time, a thin (about 1 mm) stream of fuel should escape from the "nose" of the accelerator, directed exactly into the second chamber. If the jet is low-power or curved, this is a sign of clogging of the atomizer, jets, valves of the accelerator pump. This problem is solved by cleaning them.

Air leak in intake manifold

Another reason why the engine does not develop speed may be a banal air leak in the intake manifold of the power unit. Symptoms of such a malfunction are difficult starting of the engine, its “triple”, problems with an increase in fuel consumption and, of course, a loss in the number of revolutions. This all happens due to a sharp depletion of the mixture due to unaccounted for air entering the combustion chambers.

Most often, depressurization of the system occurs due to wear on the intake manifold gasket. It is quite difficult to determine that the injection engine does not develop speed precisely because of air leakage, just as it is not easy to find the place of depressurization itself. It is better to entrust it to specialists. But there are some things you can try to do yourself. You can, for example, take a syringe with a needle, fill it with gasoline (or solarium for diesel units) and treat with fuel the junction of the manifold with the engine around the perimeter. If the gasket between them has become unusable, then gasoline will be sucked into the combustion chambers along with air. If, after starting the engine, you notice positive changes in its operation, you can be sure that the reason lies precisely in the suction.

Wrong ignition timing

It often happens that unlucky car owners, wondering why the engine does not develop speed, forget about the moment of ignition, although it is he who plays the most important role in the operation of the power unit. Timely ignition of the fuel mixture in the combustion chambers depends on it. If the ignition timing is set incorrectly, you will never, by any means and methods, achieve the coordinated operation of all engine systems and mechanisms.

In injection power units, the corresponding sensors are responsible for the correct moment. Their job is to collect information and transmit it to an electronic control unit, which in turn adjusts the angle. There are no such sensors in carburetor engines, so the ignition is set manually by scrolling the top of the ignition distributor.

Setting the correct angle on your own and without special equipment is not easy, although it is possible. At service stations, a special stroboscope is used for this, with the help of which the specialist determines the position of the mark on the crankshaft at a certain position of the distributor.

Violation of the valve timing

Timing problems usually occur when the timing belt breaks or when it is replaced. If you make a mistake in the form of a shift of at least one “tooth” between the gears of the crankshaft and the gas distribution mechanism, you will get a real problem in the form of unstable engine operation, increased fuel consumption, colored exhaust and other troubles.

In order not to get into a similar situation, work on and repair of all elements associated with it should be carried out at service stations. Well, if this is not possible, then it is necessary to carefully check and double-check the correspondence of the marks on the timing gears, crankshaft and flywheel.

Gaps between electrodes

The next reason why the engine slowly develops speed or does not develop them at all may be wrong. There was a normal car with a normally working engine, but you didn’t like something, and you decided to change the candles, but didn’t read the manufacturer’s recommendations. An error in the gap of one tenth or one hundredth of a millimeter will certainly make negative adjustments to the operation of the engine. Depending on its increase or decrease, this may be difficult starting, loss of traction, power reduction, excessive fuel consumption, etc.

When it comes to clearances, two-stroke engines cannot be ignored. For them, candles are one of the most important elements that ensure the stable operation of the motor. So, if it does not develop speed, the first step is to check the condition of the electrodes and the compliance of the gap with the recommended indicators.

Clogged air and fuel filters

Needless to say once again that filters need to be changed every 7-10 thousand kilometers, and in special operating conditions twice as often. Contamination of these elements causes difficulties in supplying fuel or air to the manifold and leads to a violation of the normal operation of the engine. The lack of normal fuel pressure in the fuel line causes a depletion of the combustible mixture, and if problems arise with the air supply, it is re-enriched. In both the first and second cases, the engine "suffocates", heats up excessively, loses power, speed, consumes more fuel.

Such a malfunction is eliminated by replacing the filter elements.

Sensor failure

In comparison with the carburetor, the injection engine wins due to the fact that its operation is controlled by electronics, and if any problems arise, the driver will know about them by an error signal on the control panel. He will only have to connect the tester and read the code to determine which of the nodes is out of order. This happens thanks to electronic sensors that control the operation of the main systems and mechanisms. But they are not eternal either.

If any of them refuses to work, the engine goes into emergency mode. Due to the fact that the electronic unit ceases to receive the necessary information, the operation of the power unit becomes unstable.

Insufficient compression

And finally, the most unpleasant malfunction, which leads to a decrease in speed and loss of engine power, is insufficient compression. It is a consequence of the wear of parts of the piston group or the occurrence (coking) of the piston rings. As a result, the pressure in the combustion chambers decreases, and part of the energy from the combustion of the combustible mixture is simply lost.

Compression is measured with a compression gauge. Its normal performance, depending on the type of engine, can vary from 10 to 14 kg / cm 2. Having found a similar problem, you should think about overhauling the engine.

If the VAZ 2110 engine is not gaining momentum, there may be several reasons.

1. Fuel system malfunction.
2. Faulty ignition.
3. Air supply is difficult.
4. Exhaust problems.

This series of problems is typical for any car, so if the VAZ 2109 injection engine is not gaining momentum, the reasons may be the same.

Problems in the fuel system are characteristic of gasoline engines, and are the most common. In addition, this trouble is also inherent in diesel engines.

Where to begin?

At the first problems with the acceleration of the car, it is worth starting to check the car with the fuel system. The most common breakdown of the fuel system of a car is the fuel pump, and there is no difference whether it is mechanical or electric. Both the first and the second with the same probability can fail at the most inopportune moment.

Difficulties with the pump may appear after a while. The car may slowly slow down its speed characteristics, and when this process reaches a noticeable state, you will understand why the engine does not pick up speed.

The point is the fuel pump, which, although not yet out of order, but not so actively supplies fuel to the engine. This inevitably leads to fuel starvation of the car, and, as a result, a loss of power.

Procedure.

1. Ignition check should start with timing marks. It is on the correctness of their installation that depends on how timely the fuel injection and spark supply will be.
2. If the marks are in order, you should pay attention to the numerous sensors, which are plenty for the injection engine. You can check the position sensors of the crankshaft, camshaft and others on your own or entrust the car to a specialist.
3. If everything is in order here, you should pay attention when the timing belt or timing chain was changed. The reason why your VAZ is not gaining momentum may be incorrect installation of the belt. Here it is enough to make a mistake by one tooth, and you can safely forget about the normal acceleration of the car.

The engine may not pick up speed 406 due to the fault of the injector, while the problem will be divided into two:

• the car does not start at all;
• the car does not work properly (this includes problems with speed, both while driving and idling, as well as all kinds of car jerks).

In the first case, the “nine” is often helped by warming up the battery or even recharging it. As you might guess, this situation occurs in winter during frosts. The reason lies in the drop in battery capacity, which may simply not be enough to start the engine.

The second way to revive a frozen car is to supply hot air through a hair dryer. This "folk" method also helps a lot.

And finally, the third reason why a car may not start is faulty spark plugs.

Methods for diagnosing a problem

For the most accurate diagnosis, you will need to use a diagnostic tester, fuel rail pressure gauge, vacuum gauge and spark gap.

1. The first thing to check is if there is a motor control ECU. To do this, simply turn on the ignition and listen to whether the fuel pump is noisy.
2. Then we look at the pressure of the fuel line. Data at the level of 2.5 - 3.0 kg / cubic centimeter are considered the norm.
3. If these parameters are normal, you can check the BITSTOP parameter on the scan tools while cranking the engine. The BITSTOP parameter must be set to "none". This indicates that the ECU receives a command to start sparking on the spark plugs and is fully operational.
4. By connecting a high-voltage arrester, you can check if there is a spark at all, and maybe the cause is poor-quality spark plugs.

Also learn about.

Air supply

Air supply can also cause weak vehicle traction. If more air enters than it should, then the composition of the fuel mixture will be disturbed. Those. it will have more air and less fuel, which will lead to a drop in thrust.

The easiest solution is to replace the air filter, which is recommended to be done every six months.

If the engine speed increases, but the speed does not pick up, the reasons may be:

• low pressure in the fuel system (as mentioned earlier);
• problems in the operation of the DMRV;
• clogged air filter;
• coked nozzle.

It is more difficult to understand the operation of the DMRV, since each car must have its own parameters, and you will still need the appropriate equipment. Even a deviation from the norm by 3 kg / h can cause significant “changes” in the operation of the engine, and not for the better.


Using the example of a 406 engine, we can say that the norm is 13 - 15 kg / h. At the same time, reducing the flow to 11 kg / h will lead to such a problem that the engine does not pick up speed or does it slowly, while increasing this figure to 19 kg / h will significantly increase fuel consumption, which is also unpleasant.

Coking of nozzles, most often, is the fault of low-quality fuel, since problems are extremely rare in the “electrical” part. To check, the injectors are often switched off one by one, while monitoring the drop in engine power. The norm is approximately 110 revolutions.

However, such diagnostics are laborious and will not give a 100% result, therefore, it is not recommended for all owners of injection systems, including for 3sfe, to clean the nozzles every year. Who knows, maybe your 3sfe motor is not gaining momentum for this very reason?

Various jerks and failures during engine operation are another side of the failure of the TPS or DMRV. In this case, it is also difficult to diagnose TPS problems, and in addition to the equipment, you will need to clearly know at what crankshaft speeds failures occur, such as jerks or power failures.

Car exhaust problems

Before you start considering this issue, it is worth checking the car's catalyst. If it is still there, you should make sure that it is not clogged. Even with the impressive characteristics of the car, when trying to “squeeze” an acceptable speed out of it at high engine speeds, they simply will not succeed. Here lies the answer to the question, why put larger mufflers on cars? It is to increase power, since the absence of a silencer can add up to 15% of power to a car.

This drawback is also relevant for diesel engines, so if the diesel engine does not gain high speed, excess oil may have got into the exhaust manifold for a long time, which also burned out, forming soot on the walls, and this is already serious. The smaller the hole in the exhaust manifold, the less the engine is capable of.

The motor in a car is the most important detail, which is why choosing a new car is based on the reliability of the heart of the car. Consider a small rating of the most reliable engines in different price ranges, allowing not only domestic, but also foreign production.

1. Small class, or B+. A fairly large segment of the market, where our Lada Granta is represented, but it did not get to the top of the reliability rating, it lost to the K7M engine from Renault. The second and third places, perhaps, should be given to the VAZ-21116 and Renault K4M engines.
2. Middle class, or C class. Here, our old friend K4M from Renault is in the lead. The second place is deservedly occupied by engines from Korean manufacturers such as Hyundai, KIA. In third place, it would be appropriate to place the engine from Renault and Nissan - M4R.
3. In the business class, we will single out the first two places: for the “junior” business class and the “senior”. In the first case, this is the 2AR-FE engine from Toyota, and in the second case, the engine from Lexus 2GR-FE.

Now find out about.

In general, the engine can stop pulling for a variety of reasons - this is one of the most common malfunctions, which can have a huge variety of reasons, and below we will consider the most likely ones, describe their symptoms and explore this issue in detail. After all, one day it can happen to each of us that the engine will lose power, without being accompanied by any more symptoms. The engine is probably not showing any obvious signs of any disease, it seems to be almost in perfect order and does not make any unusual noises and vibrations, but it just does not pull as well as it usually does. And the problem seems to be getting worse and worse every day, although you probably didn’t even notice when the engine started to pull worse for the first time.

If you are familiar with this situation, then let's look at the following reasons for reducing the engine's traction:

Poor quality fuel

First of all, you need to blame the fuel - remember where you last refueled - perhaps this is a new gas station or one with the fuel of which you had no experience of driving before. It is quite possible that this fuel simply turned out to be of very poor quality (it happens so much that you are just lucky if your engine just stops pulling - after all, for someone, the engine will probably stop starting at all until the owner completely replaces the fuel in the tank).

If you refuel at the gas station where you usually do, and nothing arouses suspicion, go to local communities on social networks, a car club in your region / district, or just a city portal - perhaps there was simply a bad delivery of fuel at the gas station.

However, most often, along with the loss of traction, the incompatibility of the engine with such low-quality fuel has other symptoms - for example, such as instability of engine speed, difficulty starting, and some others, depending on how bad the fuel turned out to be and on the car model.

But it is most likely that you can determine the poor quality of gasoline yourself by unscrewing the candles from the engine (this will require a special candle wrench) - in general, candles can often be used as the primary diagnostic method for certain malfunctions in the engine combustion chamber, since they are the ones that work most closely with this combustion chamber and at the same time are quick-detachable. If the fuel contains a large amount of metal-based additives, then the contacts of the candle and the "skirt" of the central diode will have a reddish coating (as if a red brick was crushed onto a candle).

Dirty air filter

Your air filter may also simply get dirty, and in this case, eliminating the power loss will cost you, perhaps, cheaper than all other options - just replace the air filter - you can either buy it yourself or replace it yourself.

The problem with a dirty air filter is that the fuel-air mixture that enters the combustion chamber of your engine cylinders enters there without enough air, and therefore the fuel does not burn completely, because sufficient oxygen is needed to burn it. It turns out a situation similar to a runny nose in a person - he seems to eat enough and leads a healthy lifestyle, but at certain points in his life (during illness with this runny nose), clogged nasal passages do not allow him to breathe normally.

Dirty or old spark plugs

Spark plugs can very well be dirty or excessively worn, in which case if the engine is not pulling because of them, this is also a relatively inexpensive troubleshooting option - just clean the spark plugs or replace them. However, it should be borne in mind that both periodic fouling and wear of spark plugs is an abnormal process, and the reason for this lies, most likely, somewhere deeper, or in the spark plugs themselves.

Dirty fuel filter

The fuel filter, like the air filter, can cause loss of engine power. And the physics of the process here is similar to an air filter - if in the case described above the fuel did not completely burn out due to lack of air, then in the case of a contaminated fuel filter, on the contrary, an insufficient amount of fuel is supplied. In this case, it's simple.

Mechanical problems with the engine

If all the above methods did not save, and the engine still pulls the car badly, then it is time to entrust the matter to professionals - go to a good car service and diagnose the operation of the engine - a compression check (compression ratio in the combustion chambers), for example, can say a lot about work engine, including the approach to the limit of its resource and the upcoming costly repairs.

Fuel system malfunction

It is also quite likely that the reason for the drop in engine torque is a violation of the normal operation of the fuel supply system to the cylinders, and there may also be a number of reasons that the engine is not gaining momentum, let's list the main ones:

• A faulty (dirty) fuel pump due, for example, to low-quality fuel or gasoline being sucked out from the bottom of the tank, where most of the foreign particles of dirt have settled.
• Faulty injector or oxygen sensor.
• Leakage in hoses or fuel supply pipes where air is sucked in.

Catalyst or exhaust system clogged

A dirty catalytic converter or exhaust system can also cause a decrease in engine traction. In both cases, replacing the corresponding contaminated component will help. It should be borne in mind that the catalyst, as a rule, is very expensive due to the content of noble metals in it in certain quantities.

We have listed the main and most likely causes of a possible loss of engine power - you need to remember that there are a great many such reasons, and if you were unable to install them yourself, then you definitely need to go to a car service workshop to entrust this matter to professionals.

It is important for every motorist that his vehicle works properly and is able to develop its own optimal power without any problems. However, for a number of reasons, the power unit of the machine may eventually stop gaining the number of revolutions necessary for its normal operation. In this case, the car will lose its former agility, and its traction will decrease significantly.

Symptoms

Determining the lack of revs is quite simple and every driver is able to distinguish the normal power of his car. A decrease in power is always accompanied by a deterioration in dynamics, traction, poor acceleration, as well as an increased internal combustion engine. Often a car with this problem consumes much more fuel, and the exhaust gases can either be black.

A serviceable motor always responds without delay to pressing the accelerator pedal and begins to develop more revolutions. If this does not happen or there is no tangible difference, then attention should be paid to both the engine and the fuel system.

As for the malfunctions due to which the power unit is not able to gain the required number of revolutions, it is worth noting that there are quite a few of them.

Insufficient heating of the internal combustion engine

First of all, it is worth understanding that an unheated engine is unable to fully function. For this reason, before driving, it is recommended to let the machine idle for a few minutes, or to start driving with a cold engine without rapid acceleration. But it is worth remembering that if the car is equipped with a carburetor engine, then it is better to give preference to warming up rather than a gentle start. Otherwise, the movement may be jerky, and the motor may stall.

If this system fails, then it will not work on your own and you should definitely visit a car service.

carbureted engine

In the case of a carburetor, everything is somewhat simpler - the angle is set exclusively in manual mode, scrolling through the ignition distributor. It is quite difficult to install it correctly, but still possible.

If the ignition of the mixture occurs when the piston is at top dead center, then the explosion of the mixture will occur when it starts moving down. To prevent this from happening, the ignition angle is adjusted. To correctly set the angle, it is necessary to identify the compression stroke in the first cylinder. To do this, you can take a piece of cotton wool and plug the hole in the cylinder candle. After that, the crankshaft is scrolled by the ratchet and at the start of compression, the fleece will fly out under pressure. In this case, the marks on the pulley and the front cover must correspond to each other. When the marks have converged, it is necessary to pay attention to the distributor rotor, it should be directed precisely to the contact of the first cylinder (the numbering of the cylinders is indicated on the distributor cover). If this is the case, then everything is in order with the ignition timing.

Further, if an error is detected, it is necessary to loosen the lower nut fixing the distributor. After that, slightly raising the distributor, you should scroll the rotor until it reaches the contact of the first cylinder. Having installed the rotor, the fixing nut can be tightened, but not completely.

Now you should adjust the ignition angle. This is done in the following way. The tester, or a control lamp, is connected to the positive terminal of the ignition coil and to the "mass" of the car. The ignition is switched on and setup begins. To do this, the rotor is pressed with one hand, and the vacuum regulator is slowly scrolled clockwise with the other until the control lamp goes out. After that, the distributor housing is scrolled in the opposite direction until the lamp ignites or the reading on the tester is detected. As soon as this has happened, the scrolling is completed, and the nut is tightly tightened. Thus, the ignition timing on carbureted engines is regulated.

Gasoline level in the float compartment of the carburetor

In the process of forming the air-fuel mixture, the fuel limit in the carburetor float chamber plays a huge role. If the level is too low, the amount of gasoline in the mixture is noticeably reduced, as a result of which the internal combustion engine is unable to develop sufficient power. When the level is high, the fuel mixture is enriched, but it is unable to fully warm up before entering the cylinder, which is why the speed also decreases.

In order to adjust the fuel level, it is enough to bend the float mount in the right direction and to the required limit.

Accelerator pump malfunction and clogged lines

When diagnosing, it is important to pay attention to the condition of the accelerator pump, because it is thanks to its reliability that the engine responds to pressing the accelerator pedal. The jets located in the pump in the normal state should supply fuel in a thin stream.

It's pretty easy to check. It is necessary to dismantle the air filter in order to open the view of the first chamber. After that, open the throttle and hold it in this state for several seconds. As a result, a powerful and thin jet of fuel will come out of the jet, which must be directed clearly into the second chamber. If the stream is weak or uneven, the jet is clogged and requires urgent cleaning.

Air leak in intake manifold

Among other things, the cause of a significant drop in the speed of the power unit can also be the usual air leakage in the intake manifold. At the same time, the engine does not start well, troit, gasoline consumption increases, problems arise even at idle. This is due to the fact that excess air penetrates into the fuel mixture.

It is rather difficult to find out that the injection unit has ceased to fully develop speed precisely for this reason, and it is even more difficult to find the very place where it lets air through. Most often this happens due to wear of the manifold gasket. To check, you can generously cover the joint of the manifold with fuel using a syringe around the entire perimeter of the connection. Next, you should start the engine and if you manage to develop normal speed, then the problem lies precisely here.

However, it should be understood that this method is rather primitive. For a complete diagnosis of the intake manifold, it is recommended to visit a car service, since it is very difficult to do it yourself.

Violation of gas distribution

When the timing belt breaks, the valve timing in the unit is disturbed. This also happens after replacing it, if the new belt was installed with an offset of at least one tooth of the crankshaft and camshaft gears. In this case, the internal combustion engine cycle is disrupted, fuel consumption increases, and the exhaust acquires different colors due to incomplete combustion of the mixture.

Due to the fact that replacing the belt requires certain knowledge of the operation of the engine, it is better to entrust this procedure to a car service, rather than trying to set the cycle yourself.

low compression

Perhaps the most serious problem due to which engine power is reduced is a decrease.

This happens when the parts of the piston group are worn. The consequence of this problem is the loss of energy during the operation of the internal combustion engine. Compression is checked by a compression gauge, and if the performance is below optimal, then this problem requires a mandatory overhaul of the engine. Compression in the range of 10 - 14 kg / cm2 is considered the norm, but for each car it has its own and is indicated in the documentation.

In this article, we'll take a look at a few common diesel engine problems, and how you can fix them on your own. And we will also figure out why these malfunctions can appear in a diesel engine.

The diesel engine does not pull (does not develop full power), but it does not smoke.

The most common causes of such a malfunction are a decrease in the patency of the coarse fuel filter in the car tank and a decrease in the patency of the fine fuel filter. Many conscientious drivers change the fuel filter after a certain mileage of the car, as prescribed by the car manufacturer. But we forget that any manufacturer of an imported foreign car writes the terms for replacing the filter, counting on the fact that the car will be operated on normal European fuel.

It cannot even occur to them that there may be dirt or water in the fuel, which is a common occurrence in our domestic fuel. Therefore, in order not to harm the engine and not lose power, the fuel filter should be changed twice as often, especially if you visit remote gas stations somewhere in the outback. And best of all, upgrade the fuel system of a diesel foreign car, as described in.

In order to be sure of such a malfunction, you need to change the regular opaque fuel line going from the fuel filter to the injection pump to a transparent hose (as in the photo on the left), which will be very useful in the further operation of the car (after replacing the hose, and the fuel filter, too, you will need bleed the fuel system, that is, remove air, read how to do this).

After replacing the hose (fuel line) with a transparent one, and pumping the fuel system, we start the engine, and if the fuel filter is clogged, then when the engine is running, circulating air bubbles will be visible in the transparent hose, and with an increase in diesel speed, they will be visible even more clearly. Moreover, from the presence of these air bubbles in the fuel system, the diesel engine can work intermittently (“troit”), naturally, engine power is lost from this.

We get rid of such a malfunction by replacing the fine filter, but before that it will be useful to unscrew the drain plug at the bottom of the fuel tank and drain the sediment. It will also be useful to clean the coarse fuel filter (mesh in the form of a barrel) located in the gas tank from dirt.

To do this, many cars have a special hatch (the one in which there is a fitting for connecting the fuel hose), by unscrewing which you can get to the coarse fuel filter. After all these operations, it will be necessary to bleed the fuel system in order to remove air from it (how to do this, follow the link above and read).

At idle and medium speeds, the diesel engine works normally, and at high speeds it works intermittently (“troit”).

Such a nuisance may be due to a malfunction of the gas distribution mechanism of the engine (timing), as well as due to air being sucked into the fuel system, or due to the above-described loss of fuel filter patency (the filter is clogged with dirt).

First, let's make sure whether the fine fuel filter is to blame or not and whether it is worth changing it. To do this, disconnect the fuel hose from the filter fitting (I hope you have already replaced it with a transparent one), which goes to the injection pump. Dip the end of the hose that you removed from the filter fitting into a bottle of clean diesel fuel and now start the engine.

If now the diesel engine works in all modes (at any speed) normally without interruption, then the malfunction was precisely due to a dirty fine filter and it should be replaced. If the malfunction does not disappear, then try to clean the coarse filter located in the fuel tank from dirt (I wrote about this above). Don't forget to bleed the fuel system afterwards.

If after that the malfunction does not disappear, and the fine filter is new, and you cleaned the coarse filter in the tank, then pay attention (when the engine is running) if there are air bubbles in the transparent fuel hose. If yes, then it is possible that the fuel system is leaking somewhere and air is getting into it.

Check all connections of metal and rubber fuel lines and fittings of the tank, pump, return hose (including under the bottom of the car), it may be necessary to tighten the clamp somewhere, or replace the rubber hose cracked from time to time. Typically, leaks are clearly visible in the characteristic wet spots from the fuel. After the leak has been eliminated, the fuel system should be bled (bleeded).

If you have replaced and cleaned all the filters, and no air bubbles are observed in the hose during engine operation (and everything is tight), but still the diesel engine at maximum speed (or above average) works intermittently (“troit”), then it remains to check (which by the way, it can “float away” due to a malfunction of the valve mechanism), and it’s also worth checking and adjusting the thermal clearances in the valves (read how to do this).

But sometimes this does not help, and either valves or restoration of their geometry is required. But before you remove the head for repair, you should determine why the compression is lost - due to leaks in the valve mechanism or due to piston wear.

How to do this, I already wrote and those who wish can read about it. If you are unable to eliminate all of the above malfunctions, then you should contact the services of specialists to repair the engine head and restore the timing to normal operation.

On more modern diesels, in the head of which hydraulic valve compensators are installed, interruptions in the operation of the engine may be due to a malfunction of the hydraulic compensators, for example, if one of them is stuck due to dirty oil. In general, such diesels like better oil and more frequent oil changes (and filters too), just like turbo diesels.

To eliminate the jamming of the hydraulic compensator, in any case, you will have to disassemble the head, followed by washing or replacing parts (if they have scuffs).

When the diesel engine is running, it knocks, and if you sequentially disconnect the fuel lines from the injectors, then the knock disappears.

Such a malfunction may occur due to the failure of some kind of nozzle (for example, the nozzle needle may jam in the open position). You can determine which cylinder injector is out of order by disconnecting the high-pressure fuel lines from the injectors one by one.

Well, the last reason why a diesel engine can smoke and not develop full power is the unsatisfactory operation of the nozzles (for example, wear and loss of tightness of the needle and its seat - I wrote about the diagnosis and repair of nozzles on my own in), but before unscrewing them from the engine and take it to specialists for inspection (pressure testing), first perform the above steps, starting with replacing the air filter.

By the way, I advise you to clarify the mileage of your car, I mean the real mileage (how to find out the real mileage,), since on modern diesel engines with a common rail system, modern electro-hydraulic or piezoelectric nozzles (I wrote about them) walk on our domestic fuel as the rule is no more than 150 - 200 thousand km. And if your odometer does not have low mileage, as described just above, and the car is modern, that is, with a common rail fuel system, then injector diagnostics are definitely needed.

These are far from all possible malfunctions of a fairly run-through diesel engine, and there are other ways to eliminate them, but I will try to talk about them in one of the following articles (we find the article).

I hope this article will help those drivers who like to fix most diesel engine problems, and the whole car with their own hands, good luck to everyone.