Diagnostics of a modern diesel engine as a whole and its individual systems usually takes much more time than in the case of gasoline units. To determine the malfunction, a combination of professional equipment and high qualification of the master is necessary. But even in the presence of such a base, one has to resort to specific diagnostic methods.
The main difficulty in diagnosing is that it has fewer system parameters, the evaluation of which allows you to immediately find a malfunction. One of these parameters is the composition of the air-fuel mixture. In a diesel engine, its range is wider compared to a gasoline engine, as a result of which it is difficult to unambiguously judge whether the mixture is poor or rich for a certain mode. Therefore, the diagnostician has to compare many indirect indicators. This is reminiscent of a detective investigation with weeding out suspects and gradually finding the true culprit.
deductive method
The most difficult task is to identify floating faults that leave almost no evidence and reveal themselves only in certain engine operating modes. Only an experienced diagnostician-detective armed with a good scanner can handle it. Luckily, over several trips, comparing key operating parameters of the main engine systems, he can catch the culprit. But often the diagnostician has to use workarounds to narrow down the suspects.
To describe the course of the investigation, consider the most common cases when a car arrives at the service with obvious and permanent malfunctions.
The fuel equipment is most often to blame for the difficult start of the engine and the instability of its operation in various modes. But it is important to ensure that other causes are excluded - for example, problems with the cylinder-piston group, namely a decrease. You can’t just measure it on a diesel engine, you will have to dismantle the fuel injectors or glow plugs, which is fraught with damage. This is where specific diagnostic methods come to the rescue.
First, using a scanner, they check the fuel supply correction for the cylinders and the dynamics of changes in fuel pressure in the rail. The control of these parameters is included in the vehicle's on-board diagnostic system. If the pressure in the rail is built up more slowly than expected, a check is carried out using external meters. First, cut off the low pressure line to the injection pump by connecting a pressure gauge or vacuum gauge (depending on the type of supply circuit). Next, check the pump. A pressure tester is connected to it so that the high-pressure fuel pump pumps fuel "into the wall": in the starter scrolling mode, it develops the maximum pressure, which is compared with the required one. By the difference in indicators, the condition of the pump and its metering valve is assessed.
With the help of this tester, the correctness of the readings of the fuel pressure sensor in the rail is also checked. In this case, the device is connected to the ramp instead of one of the fuel injectors (it's okay that it will temporarily work without one cylinder). The tester and scanner readings are compared and the lying sensor on the ramp is cut off.
By analyzing the values of the correction of the fuel supply, problematic cylinders are reliably identified. If one of the injectors is underfilled or the combustion pattern of the air-fuel mixture is disturbed due to a decrease in compression, the engine control unit will try to correct the situation by increasing the injection duration. In this case, the correction values will differ markedly by cylinders.
Next, the diagnostician calculates the culprit: is it an injector or a decrease in compression in the cylinder? The second parameter is often evaluated indirectly so as not to unscrew the injectors or glow plugs to connect the compression gauge: they are easy to damage, especially for engines with high mileage.
The first method is included in the on-board diagnostics functions of some car brands. According to the uneven rotation of the crankshaft at the time of its scrolling without starting the engine, the “brains” themselves determine the spread of compression across the cylinders. This is an express method with low accuracy and repeatability of results. He is able to calculate only heavily passed cylinders and will not notice less obvious deviations that may affect the operation of the engine.
The second indirect method of measuring compression is more universal. A sensor is hung on one of the battery wires, which registers the peaks of the current consumed by the starter when the crankshaft is scrolling. The higher the compression in the cylinder, the greater the consumption in the compression stroke. The sensor is a current-to-voltage converter. It is connected to an oscilloscope, and already on its screen, the values \u200b\u200bof the peak voltages across the cylinders are compared. If they are the same, then the compression in the cylinders is considered optimal. Otherwise, using synchronization with other signals, it is possible to “tie” specific cylinders to current peaks. Or go further - take a real measurement, simultaneously using a compression meter and a current sensor. Then for a particular type of engine, we get correlated (interrelated) values (amps and bars) that will be useful in the future.
If the compression in all cylinders is normal, we direct all attention to the fuel injectors. The electrical part of the injectors is checked with a tester, which measures their resistance and inductance, and also checks the insulation resistance. The hydraulic part (as well as the high-pressure fuel pump) can be fully tested only on expensive stands, which are mainly available to specialized enterprises for the repair of fuel equipment. In the arsenal of conventional service stations there is only a familiar kit for checking the so-called return line (a line for draining fuel from the injectors into the tank). Connect volumetric flasks to the nozzles and watch how they are filled. At the same time, it is not at all necessary that, for example, an injector that decently underfills fuel into the cylinder will drain much larger volumes into the return line compared to others. This test is carried out in addition to other activities. If you draw unambiguous conclusions only on the basis of its results, you can groundlessly condemn workable elements.
EAGLE AND TAILBranded diesel technical centers (for example, Delphi-Service or Bosch-Service) are far from being in all cities. Car owners are left with ordinary mono- or multi-brand car services. Monobrand services that specialize in one brand or several, but belong to the same concern, usually have a large but narrow experience. Over the years, they have stuffed a lot of bumps on some models and often, even without diagnostic equipment, they can immediately diagnose the symptoms of malfunctions. And they usually have the ability to temporarily supply known-good items to pinpoint the culprit. But even such service stations sometimes fail. There has always been a significant turnover in this area. Sooner or later, a seasoned specialist leaves for another technical center, and a less experienced master takes his place. In addition, if some complex defect has not yet been encountered by service diagnosticians, their system knowledge, as a rule, is not enough to make an accurate verdict. Employees of multi-brand services are usually more savvy in fundamental matters: obliges the flow of various machines and systems passing through their hands. This is not about "temporary workers", who have one universal Chinese scanner for all occasions, but about serious service stations. Professionals use a wide range of diagnostic equipment and check many parameters. However, sometimes it takes them much longer to make a correct diagnosis than their colleagues from a monobrand service. And they will not be able to perform some complex procedures due to the lack of narrow-profile equipment or equipment. |
Standard scheme
Diagnostics of other diesel systems is easier, but you still can’t do without special equipment. Before removing the glow plugs for inspection, measure their voltage and resistance. The best test is to connect a current sensor used to measure compression. Usually candles are controlled by a separate block. The sensor is hung on its supply wire and the total current consumption is recorded: by its significant drop, you can immediately determine that one or two candles are not working. Next, we move on to checking specific candles.
For diesel engines, the vacuum system is usually more complex than for gasoline engines, therefore, auxiliary equipment, a smoke machine, is often used to check the tightness of its lines. Leaked smoke will definitely indicate a leaky place. This apparatus is also used to check the tightness of the intake tract of the pressurization system. But its control part (if it is of a vacuum type) is tested in a combined way. The readings of the vacuum gauge connected to various points of the system are compared with the data received from the scanner on the control action on the solenoid and boost pressure.
The condition of the particulate filter can be accurately read by the differential pressure sensor. In any diesel car, the on-board diagnostics of this unit is very developed, and it is quite enough to obtain accurate data. The fact that the filter is clogged above the permissible level will be indicated by increased back pressure in front of it.
The operation of the exhaust gas recirculation (EGR) valve is also relatively easy to check. Electric valves are usually equipped with a feedback position sensor. The air consumption of the engine is also taken into account. A diagnostician using a scanner is able to determine the condition of the valve and its incorrect operation.
When running a diesel - a separate issue. Against the background of the general loudness of the motor, it is difficult to determine their true source. The main noise of a diesel engine is associated with the characteristics of the combustion of the air-fuel mixture in the cylinder. If it takes on an anomalous character, for example, due to a faulty injector, the sound is amplified. In this case, turn off one nozzle at a time to determine the "loud" cylinder. As soon as the desired one is deactivated, extraneous noise will disappear. True, such a maneuver will not work if two or more cylinders are noisy.
NOT A PANACEAA full diagnostics of diesel fuel equipment can be carried out only in the branded technical centers of the manufacturers of these systems. In their arsenal there are multifunctional stands for testing injectors and high pressure fuel pumps in various modes and equipment for repair. But even such a technical base does not always give a 100% result. There are cases when proven injectors are installed on a car that have successfully passed all the tests at the stand, but the malfunction does not go away. And the reason is not in useless equipment or low qualification of employees, but in specific operating modes of fuel equipment in real conditions - even the most sophisticated stands are not able to recreate them. Often there are problems with repaired parts and assemblies. far from every service station can carry out such work, and even with a competent approach, misfires are inevitable. In some cases, the restored injector, which has passed all the checks, refuses to work adequately at all, and in others it is capricious only in some engine operating modes, although the test bench ran it through all the control points and assigned the correct fuel correction code. As a result, you have to change an expensive nozzle, despite the fact that the owner of the car has already spent a lot of time and money. |
Thank you for your help in preparing the material, the training and practical center of the company Interlaken-Rus.
If you think that the condition of your car’s engine requires serious overhaul, and that the diagnostics indicate that the engine’s life is almost completely exhausted and the capital will no longer save it, then there are only two options: either buy a new engine or a used one . But here there is an opportunity to save money and buy a used contract engine in good condition. An essential feature of such a purchase is the need to know how to choose a diesel contract engine. Still, the unit was in use, and although it arrived from Europe, you cannot 100% know the reasons why it got into the warehouse under the contract, so there is a certain risk. If you are not a specialist, you should entrust the choice of a contract diesel engine to a professional, preferably one who can not only choose a high-quality engine and vouch for its quality, but also install it in your car, providing a guarantee for their work.
But how to choose a used diesel engine if there are no auto mechanics you know and you have to inspect it yourself? How to distinguish junk from an engine in good condition and determine its real value? In this publication, we will try to analyze all the intricacies of buying a contract diesel for your car.
First, you must inspect the engine very carefully from all angles. Pay attention - the engine is not washed, because if the engine is washed, then the seller can thus try to hide defects and obvious cylinder block problems. Very often, sellers of used motors wash them to remove oil drips, thereby disguising the fact of leaking seals.
If you find leaking seals after installing the engine, this may lead to the need to replace them, or even more serious problems, if after installation and start-up you do not notice leakage, then problems will overtake the car already on the road. It is much cheaper to change oil seals on a removed engine, but you run the risk of finding out when it's too late. Therefore, the first advice is to run away from a washed engine, no matter how clean it looks. It is not necessary to wash a good honest engine, its quality is far from being determined by external brilliance and cleanliness.
So, you have chosen an engine that does not look like a clean boiler. What's next? Next, you should inspect the cylinder head for oil leaks from under the cylinder head gasket. If there is a leak, we immediately refuse to buy, with this option there may be problems in the future.
The third step we must unscrew the engine oil filler cap and inspect it from the inside. Here we are concerned about two points: the presence of oil soot and emulsion. If carbon deposits are present, this indicates that the oil was poured into the engine, to put it mildly, of poor quality. The same effect can occur if the oil has never been changed. But worst of all, if you see an emulsion on the cap, which forms when the oil mixes with the coolant. And if there is an emulsion, then almost always this indicates that the cylinder head gasket is broken, or there is a crack in the cylinder block or in its head. In the best case, the emulsion will indicate a crack in the oil cooler, but the presence of all these cracks suggests that the engine has most likely been in an accident, which means it is full of unpleasant surprises.
Oil soot or emulsion on the oil filler cap? We refuse to purchase this diesel engine. Let's see the next one!
Next, we must spin the engine a few full revolutions. We do this not to check compression, which cannot be checked in this way if the engine has been in storage without oil with the injectors removed for a long time. But in this way, you can make sure that the piston system and the crankshaft rotate freely and do not wedge during rotation. If cranking the engine fails, check if the high pressure fuel pump was removed from the diesel engine. In this case, turning will turn out only under one condition: if on your diesel model there is a separate drive on the high-pressure fuel pump, and, accordingly, when it is removed, the gas distribution system is not disturbed. Thus, if wedging is clearly noticeable when turning the engine, we do not take such a contract diesel.
The next step in the visual inspection is intake manifold check diesel engine. It should be borne in mind that there is always an oil film in the collector, this is completely normal. It is not normal if there is a large amount of oil carbon deposits in the intake manifold. The fact is that in modern diesel engines, an exhaust gas recirculation system (Exhaust Gas Recirculation, EGR) is installed to reduce toxicity. This system is designed to reduce the toxicity of exhaust gases, including to reduce the content of nitrogen oxides in them, and works according to the following principle: as a valve that, in some operating modes of a diesel engine, connects the exhaust manifold space to the intake manifold throttle space. As a result, part of the exhaust gases enters the cylinder through the intake manifold, where the exhaust gases are burned. This, of course, is accompanied by the formation of carbon deposits in the intake manifold, but if there is too much carbon deposits, this will indicate a malfunction in the EGR system or that the engine mileage is more than stated.
Ask the seller remove the exhaust manifold from the contract engine for inspection outlet conditions. The main thing you need to make sure is that carbon deposits in the exhaust windows are present in the form of dry soot. Oil should not be in any case, this is important.
The last thing we can do in the process of external inspection is to ask the seller to suspend the engine. This will give you access to inspect the diesel engine from all sides, make sure that all engine mounts are intact and that the engine pan has no dents or, worse, cracks.
Thus, even on your own, you can conduct, if not a full-fledged examination, then at least protect yourself from mistakes in choosing a diesel engine and thereby increase the likelihood that you will buy a good contract engine. However, this method cannot be completely ruled out. A used diesel engine can show itself from the most unexpected side, since you will never know the whole truth about the conditions under which and how it was operated by the previous owner.
Therefore, it would be most reasonable to order a contract engine from a trusted seller. The main criterion for choosing a seller will be the presence of good reviews among car owners, and it is desirable if these car owners drive the same car as you. The right seller will stock the best performing engines in their warehouse, provide engine installation services to customers' vehicles, and provide a warranty for testing. It should be noted that the guarantee for used units is not provided for under the current legislation, therefore, if the seller gives a guarantee, this indicates that the engines he offers have been checked, diagnosed, all replaceable consumables on the diesel engine have been replaced, and new oil has been filled in.
Never buy a car without first checking it in motion.
Body and wheels.
These nodes are required for verification, it is better to entrust this procedure to knowledgeable people. There may be hidden defects in the body.
And the wheels are those 4 points that connect your car with the road, if the tires are used, they need special attention.
But still, in a diesel car, the main thing is the engine.
During testing, pay attention to the softness of the clutch pedal and gear lever, the steering wheel, which should turn without significant effort.
You should also make sure that the accelerator pedal operates smoothly, steadily and without sticking, and the speed drops immediately after the pedal is released. If this is not the case, then the cause of the problem may be a clogged fuel drain line or fuel leaking from the high pressure fuel pump.
Uncontrolled fluctuations in the frequency of rotation of the crankshaft.
Some diesel vehicles are subject to the phenomenon of uncontrolled fluctuations in the crankshaft speed. In this state, the vehicle picks up speed instantly regardless of the position of the accelerator pedal, which is usually caused by air being sucked into the fuel system. This shortcoming can be corrected, but sometimes it will take several hours to
find a leaky spot. If the car suits you in every way, except for uncontrolled fluctuations in the frequency of rotation of the crankshaft, then do not refuse it, just demand that this drawback be eliminated before buying.
Hypothermia.
Keep an eye on the temperature gauge while driving: if it never goes past the second half of the scale, then there is a possibility that the engine has been running at low temperatures for too long, which negatively affects the operation of the lubrication system, fuel efficiency and leads to increased wear of internal parts engine. Engine operation at low temperatures may be accompanied by the appearance of a white deposit or deposits inside the oil filter, oil sump breather hose and on the dipstick. This car is not worth buying.
Overheat.
Watch the temperature gauge for overheating, which is even more dangerous for the engine. Overheating is usually caused by inefficient operation of the cooling system, which is caused by scale and rust in the system, radiator contamination, air locks, or insufficient coolant. Check the coolant level and look for possible deposits in the pipes.
Other possible causes of overheating are incorrect fuel injection timing (which is easy to fix) or faulty injectors (which are more expensive to repair). If you have a suspicion that the engine is prone to overheating, avoid buying such a car, as overheating can lead to engine failure.
Attention! Under no circumstances should the engine be run without coolant, as severe damage may result. Carefully monitor the condition of the cooling system hoses, as a coolant leak can lead to irreversible consequences.
You need to know what to look for when testing it, so that the purchase does not disappoint you later and does not require additional unforeseen investments in repairs.
Otherwise, instead of the expected use of all the possible advantages of a diesel engine, you can get a full set of its inherent “minuses”, in the form of poor starting, increased smoke and high fuel consumption.
Even before going to the car market, you need to clearly determine for yourself which of the main characteristics of the engine are most important to you. In this matter, compromise solutions will inevitably have to be sought, since there is no universal engine and it cannot, for example, be simultaneously powerful, “not voracious”, that is, economical, reliable, and cheap to repair.
As a rule, small diesel engines, in general, have good fuel efficiency, but on the other hand they are less reliable and have a shorter resource than more powerful engines. In most cases, a large displacement of the engine indicates a fairly high level of reliability, but one should not expect great efficiency from such a diesel engine compared to small engines.
Also, diesel engines without turbines are considered more reliable compared to turbocharged "brothers". In turn, turbine engines have better power characteristics, although they are less economical.
How to check diesel when buying
Having decided in advance what kind of diesel engine you need and choosing a suitable car in the car market, carefully examine the engine.
1. Inspect the power unit for oil leaks, coolant, indicating that the engine has overheated. Traces of oil sweating on the motor are not so dangerous, but it is better that they are not on the oil seals.
2. Remove the branch pipe connecting the air filter to the intake manifold or, in diesel engines with a turbine, the air filter to the turbine. If traces of oil are visible in the pipe, then this may indicate a severe contamination of the air filter or, in the worst case, a large wear of the engine cylinder-piston group.
3. Try to start the engine. If the hot engine did not start immediately, “half a turn”, then this may be a sign of some kind of hidden defect. Test runs are best done several times, with different intervals between them. At the same time, do not press the gas pedal and do not warm up the glow plugs.
- If the engine starts normally, pay attention to the exhaust gases when starting. If the engine is hot, then there should be no smoke at idle. Only a small emission of smoke is possible directly at start-up.
- Sounds reminiscent of soft tapping, like rolling stones, are normal for a diesel. Sounds that fall out of the general rhythm should be alarming, especially if they continue even after increasing the speed.
After starting the engine and letting it idle a little, gradually increase the speed to 3-4 thousand rpm, while the engine should not vibrate and twitch. At the same time, evaluate the color of the exhaust gases. If at the same time with an increase in speed, blue smoke appears, then this may indicate late ignition or other problems in the engine.
Accelerate the engine rapidly by pressing the gas pedal. At the same time, keep an eye on the engine and exhaust. If the engine vibrates at high speeds, and the smoke has a bluish color, then in such operating modes there will be a significant loss of power.
If the smoke is black and knocks are heard in the engine, then it is better to refuse to buy such a machine.
How to check compression on a diesel engine and other nuances
1. Check the compression in the engine. This is most accurately done with a special device - a compression gauge in accordance with the instructions. For a diesel engine, 36 atmospheres is considered an acceptable value, and at least 31 atmospheres is acceptable, while the spread in the pressure value across the cylinders should not be more than two atmospheres.
2. In the absence of a device, compression can be assessed by eye. Start the engine and carefully remove the oil filler cap. After that, put the lid without screwing it on the opening of the neck. If at the same time the cover is thrown off by the outgoing gases, then not everything is in order with the compression in the engine. However, this is not the most reliable way to check and high-quality diagnostics can be done at the service station using special equipment.
3. Let the motor cool down a little and open the radiator cap. Top up the radiator with coolant to the brim. After that, close the cap, start the engine, wait until the thermostat opens and see if air bubbles come out of the radiator when the engine is running. Such bubbles may indicate a leak in the cylinder block gasket or damage to the block itself.
It is advisable to check how the diesel engine starts “cold”, that is, in winter
If the engine starts without problems, just as well as at high temperatures, then we can say that everything is in order with compression, as well as with the operation of the cold start system.
At "idle" diesel should work without interruption. It can work a little “harder” in “cold” mode - this is allowed, as this may be due to a special cold start system that specifically shifts the injection advance angle at low temperatures to improve engine starting conditions in such conditions.
Of course, it is impossible to test a diesel engine, and indeed the whole car, without testing it in real road conditions. Test the power unit by letting it run for a few seconds in extreme conditions and this will be enough to identify possible problems.
If you need a car not so much to drive it, but as an exciting hobby that involves relentless fine-tuning of the car to working condition, then you may well focus solely on the price criterion.
However, in most cases, the car is still chosen as a means of transportation, while it is a reliable means that does not require additional significant financial and time investments.
In order for the new acquisition not to disappoint you later, it is important to avoid all the "pitfalls" - hidden defects inherent in a particular car that interested you in the car market.
Otherwise, instead of taking full advantage of the advantages of a diesel engine, you will get an unpleasant set of its shortcomings - everything that faulty, worn-out diesel engines “sick” with - poor starting,
increased smoke, increased fuel consumption.
The first thing to do - even before going to the car market - clearly define which engine characteristics are most important to you. Unfortunately, most power units cannot be powerful, reliable, economical, and have good maintainability at the same time ... Regrettably, compromises will have to be found.
Small engines (installed on small cars) generally have good fuel efficiency, however, they are less reliable, less durable and have more modest power characteristics compared to their "older brothers".
The large working volume of the power unit, as evidenced by statistical calculations, provides it with a greater level of reliability.
Non-turbo engines, in comparison with turbocharged designs, are more reliable, durable and at the same time have better fuel economy levels.
Turbocharged engines, on the other hand, although less reliable and have a special “appetite”, are best suited to those who put power in the first place.
At the beginning inspecting a broken engine- for the presence (better, of course - absence) of oil streaks, traces of coolant ejection, indicating that the motor has overheated.
Traces of oil sweating on the engine may be present (slightly). It is highly desirable that they be completely absent on the seals.
We remove the pipe that connects the air filter and the intake manifold (in turbocharged models - the air filter and the turbine). The presence of a large amount of oil in the pipe, at best, indicates a serious degree of contamination of the air filter or the crankcase exhaust system, at worst, it is the result of severe wear of the cylinder-piston group.
We start the engine. If “hot” it did not start with a half turn, then this should be taken as evidence of some kind of hidden defect. It is necessary to check several times, with different intervals between runs. In this case, you do not need to press the gas pedal and warm up the candles - there is no need for this. If the seller insists on such actions, then he deliberately tries to hide from you the presence of a defect in the power unit.
Pay attention to exhaust when starting the engine. At idle, there should be no smoke on a hot engine. Only a small emission of smoke is allowed at start-up.
small rattling in the motor(“rolling pebbles”) is the norm for diesel engines, but knocks that stand out from the general rhythm should alert you - especially if they persist with increasing speed.
Gradually increase the speed. From idle, we gradually move to a value of three and a half - four thousand revolutions per minute, watching the motor - it should not twitch and shake.
Let's do the same operation again. evaluating exhaust color. If, with an increase in speed, ragged gray smoke appears, then this indicates either late ignition or other defects in the motor.
Press the gas pedal hard and again observe the engine and exhaust. If the power unit shakes, and torn blue smoke comes out of the exhaust pipe, then at the speed at which this happens, there will be a significant loss of power.
If there are knocks or black smoke coming out of the exhaust pipe, it is better to cross out such a car from your list.
If everything is in order, we continue the inspection. The compression in the engine must be checked at the service(acceptable value - 36 atmospheres, permissible - not less than 31, the spread of values by cylinders - no more than two atmospheres). However, it can be preliminarily assessed on the spot. Carefully unscrew - with the engine running at idle - the oil filler cap. If after that, when you try to put the cover on the hole, it is thrown away by the gas stream, this is definitely a bad sign.
However, if this does not happen, this does not guarantee the absence of problems with compression. Diagnostics must be carried out at a service station - besides, it will be possible to check there oil pressure in the oil line with a hot engine at idle. (An acceptable value is at least one atmosphere, for turbocharged power units - at least one and a half atmospheres. Readings are taken using a mechanical pressure gauge).
Let the engine cool down (at least to 50? C), open the radiator cap, add coolant to the edge, close it. Then the engine must be started, and after the thermostat opens, see (with the engine running) if the air bubbles from the radiator. If this is the case, then either the head of the block, or the gasket, or the block itself are leaking.
Checking the start of the power unit "cold" implies - ideally - its launch at the temperature at which it will be operated in winter (thus, in summer it will not be possible to identify all possible defects by this method, but still it should not be neglected in the warm season).
If the engine starts up as quickly as it did “hot”, then everything is in order both with compression and with the operation of the cold start system, glow plugs, battery, starter.
At idle, the power unit should work without interruption. It is allowed to work a little harder in the “cold” mode - the reason may be the special cold start systems that some high-pressure fuel pumps are equipped with (they “deliberately” shift the advance angle of diesel fuel injection at low temperatures in order to improve engine start).
Naturally, without testing engine operation in real road conditions not enough. Only by recreating in practice all possible modes of operation of the power unit, it will be possible to understand how good it is.
Testing in extreme conditions, of course, should continue for several seconds - this will be enough to "diagnose" possible problems, and will not lead to their creation.
In order to check the correctness of the injection pump regulator, it is necessary to sharply press and release the gas pedal. If the engine quickly returned to idle - everything is in order. If slowly - and at the same time blue smoke continues to flow from the exhaust pipe in the reduction mode - the turbine or motor is faulty. If there is no smoke, but the power unit returns to idle slowly, the injection pump regulator is faulty.
If there are no extraneous knocks in the motor, exceeding the heating rate, significant smoke, a drop in power in certain driving modes, this is a good sign.
