An automobile power plant may not develop the necessary power, and the driver pays attention to this, as a rule, when the drop in dynamics is already obvious. It is unlikely that you will not notice this if the car accelerates with great difficulty on a dry, hard and even road surface. What is the reason that the engine power drops, and what can be done in this case?
Signs of low engine power
In essence, if the acceleration time of a car "from zero to hundred" increases by more than 25 percent, and the optimal speed decreases by 15 percent or more, this is a clear sign. Of course, experienced motorists, even without any measurements, are able to determine the decrease in the power characteristics of the power unit of their 4-wheeled pet. However, in order not to get confused, there is a certain chronometric pattern associated with measuring the “maximum speed” at various speeds. For example, at the 1st speed, the measurement is carried out up to 38 km / h, at the 2nd - up to 52 km / h, etc.
In addition, in order to be able to determine the drop in the power of the power plant at the very beginning of the problem, one must not ignore the secondary signs that indicate this. Let's consider the most common.
How to determine the power performance of the power plant
In the process of diagnosing 4-cylinder internal combustion engines, it is recommended to turn off three cylinders, and use the resulting mechanical losses as a load. If diagnostics of 6-cylinder or more power plants is carried out, additional loading devices are used simultaneously with the shutdown of a certain number of cylinders, which makes it possible to conduct a study much more efficiently.
To date, there are various techniques that help the owner independently check the power characteristics of the power unit of his car. For example, install special equipment that can track the slightest changes in the functioning of the internal combustion engine, a drop in dynamics, etc. Only the price of such devices is quite high, and not every Russian motorist can afford to buy them.
Note. It is more expedient to put these devices on sports cars, the operation of the internal combustion engine of which requires regular checks.
Fortunately for motorists, there is also a budget diagnostic option. It implies the presence of a computer, a special program and a cable for integration with the on-board computer (BC) of the car. As soon as the driver drives the car for a certain distance at different speeds, the computer will automatically calculate the power of the car's power plant.
Attention. Despite the fact that this verification method has a considerable share of errors in the readings, it is widely used by motorists in many countries of the world. The method gives at least a general idea of the power characteristics.
But still. Only a dynamometer can provide the most accurate indicators. Representing highly professional equipment, it is an indispensable component of any well-known car service.
Checking the Nissan GT-R on the stand (video)
Reasons for the decrease in dynamics
Experts believe that the main reasons for the decline in dynamics are:
Petrol units
As a rule, the reasons for the drop in throttle response on gasoline and diesel internal combustion engines are the same, but there is still a difference. The power of a gasoline power plant implies a ratio with crankshaft speed. Unlike diesel units, the power characteristics of gasoline internal combustion engines directly depend on the speed described above. The higher they are, the more dynamics the motor produces. And if an engine powered by gasoline fuel, for whatever reason, is not able to deliver maximum speed, its dynamics decreases accordingly.
The crankshaft rotation speed decreases for one simple reason: due to overheating of the internal combustion engine. This often happens in the hot season or when driving for a long time in a traffic jam. Obviously, it is highly undesirable to allow the internal combustion engine to overheat.
Some foreign cars are simply not designed for our climate.
There are other reasons for the fall in the dynamics of a gasoline internal combustion engine. For example, an incorrectly adjusted accelerator pedal. An elementary reason, however, capable of significantly affecting the efficiency of the internal combustion engine.
Diesel engines
Recently, problems with Japanese diesel power plants have often been observed. It is interesting that after the line of 100 km / h the engine does not give out any problems, but before that it behaves extremely badly: it does not pull uphill, starts badly, etc.
The main reason for a decrease in throttle response in a diesel engine is the restriction of fuel supply. Most experts agree with this opinion. Indeed, this happens in 80 out of 100 cases. The remaining secondary problems are associated with the difficulties of air leakage, with a frozen fuel pipe (a common problem for Russian drivers), etc.
The next popular reason has to do with injector wear. For example, if a car from a “secondary” plowed its own, its nozzles will definitely wear out. As a result, the machine will smoke a little. This can be repaired, but most drivers sell such equipment, but first they go to the trick to eliminate the smoke and sell the pepelats at a higher price.
Black smoke on a diesel engine is not always as dangerous as on a gasoline engine.
The trick is sometimes associated with adjusting the fuel supply, a kind of "crushing" power. The initial revolutions of XX are restored, the car no longer smokes, but it does not pull either. Checking the “dark horse” is quite simple: you need to return the XX speed to its previous position, if smoke appears, then the nozzles need to be repaired.
Another reason for the decrease in the power characteristics of a diesel internal combustion engine is the jamming of the distributor timer piston in the injection pump (high pressure fuel pump). This is especially clearly indicated by the loss of dynamics at high speeds.
It is also noteworthy that it does not always indicate a problem with dynamics on cars with a diesel engine. Any such car, if you fully depress the accelerator pedal or start abruptly from a place, will smoke in black.
On turbocharged internal combustion engines, the reason for the drop in power is most often a bad turbine. It is diagnosed by removing the rubber tube from the injection pump. Then carry out the corresponding measurements with a manometer. At speeds up to 4500 per minute, if the turbine is in good condition, the readings should indicate at least 0.5 kg / cm2.
The difference in the reasons for the drop in dynamics may also be due to the difference between the injection and carburetor engines. The table below shows the most common situations in which power does not develop on the injector and carburetor internal combustion engine.
Table: why the power characteristics of the motor fell (injector and carburetor)
| Injection ICE | Carburetor ICE |
| Dirty fuel or air filters | Inadequate opening of carburetor dampers |
| Fuel pump filter screen clogged | Accumulation of dirt in the carburetor and clogged fuel pump fittings |
| Incorrect operation of the vehicle ECU | Drop in pressure or malfunction in the needle valve |
| Accumulation of dirt in the nozzles | Float element malfunctions |
| Malfunctions of the fuel pressure regulator, the main sensors, the operation of which is associated with the engine and breakdowns of the lambda probe | Reducing the capacity of the jet |
| - | Faulty economizer valve |
Poor ICE dynamics due to a catalyst: how to check
The topic of falling dynamics due to a clogged catalyst should be given a separate paragraph. This malfunction is very common among motorists lately, questions about this are often found on the forums.
We will not delve into the thematic jungle regarding what a catalyst is and why it is needed. Consider only the main signs indicating its malfunction. And a drop in ICE power is not the only symptom.
The main sign, of course, is the light bulb "Check". However, a malfunction of the catalyst is not always detected so easily, in most cases it passes gradually, and the “Check” signal is not displayed immediately. On the other hand, the throttle response of the internal combustion engine decreases, the overall dynamics of the speed increase decreases, and starting is difficult.
To remove the catalyst or not is the choice of the car owner, but it should be remembered that there is nothing “very superfluous” in the car
The reason for the drop in power characteristics can also be clogging of the bobbin combs. Because of this, the throughput of the catalyst decreases, since the gases that did not have time to pass the catalyst “crush” the power of the power plant.
Note. The honeycombs of the bobbin can not only become clogged, but also collapse or melt over time.
Problems with the catalyst can also be associated with abrasion of the platinum layers. The lambda sensor instantly notices this and gives a signal to the driver.
You can check whether the catalyst is working normally or not by the strength of the gas flow. If it is difficult to block the flow by hand, then everything is fine with the catalyst, and when it is clogged, the flow will be weak.
How to increase capacity in simple ways
Every experienced motorist knows and uses his own, favorite way to improve the former dynamics of the car. Let's consider the most popular ones, but let's not forget that only the elimination of the causes that contributed to the drop in the power characteristics of the internal combustion engine will guarantee the return of former positions.
- Use fuel with a higher octane number (OC). Indeed, the higher the OC, the better the fuel will resist self-ignition during compression. This will directly affect the greater power from the gas explosion.
- The use of "Suprotek". This is a lubricant, which is a composition of several components. This is not an additive or an additive, but a special composition that interacts with the metal surfaces of the internal combustion engine elements. Perfectly helps to eliminate the wear and tear of metal surfaces.
- Replacing the classic air filter with a modernized one. In this way, a richer mixture can be supplied to the engine.
- Exhaust system change. Forward flow increases power.
- Turbocharged.
- Replacement of worn parts and much more.
In a word, it is necessary and possible to bring the engine of your car back to normal. It is recommended to do this in professional car services, but if the driver has specific knowledge and the required equipment, in his own car garage.
Many at least once had to deal with a situation where the engine that had previously worked perfectly was “blown away”, the car seemed to grow an anchor from behind. The reasons why the engine does not pull and does not gain momentum are various, but it is not difficult to recognize the signs of the majority even without the skills of an automobile diagnostician or minder.
Common causes for all engines
The characteristics of the motor specified in the passport data of the car are provided under certain conditions. This is the filling of the cylinders with air, which is the working fluid in the internal combustion engine, corresponding to the norm. This is the ability to heat it up to the desired temperature in time - to supply a certain amount of fuel of the proper quality and set it on fire in time (the pressure peak for maximum efficiency should occur at the moment the piston passes top dead center).
ICE duty cycle
The loss of engine power, regardless of its design, is the result of a number of common causes. Let's start with fuel: its quality remains lottery, while the engine is tuned to a certain grade. That is, the mixture prescribed in the injection maps or specified by the carburetor settings can deviate from the ideal one, and the burning rate of the mixture changes. So, if problems appeared immediately after refueling, you yourself understand which way to look.
Filling the cylinders with air is rigidly connected with the valve timing. It is enough to leave the marks, as the cycles of the internal combustion engine will be shifted: already a difference of 1 tooth can significantly reduce the power of the motor. Moreover, it is not necessary for a belt or chain to jump - more and more motors receive keyless pulleys, which require rigid fixation of the shafts with special devices during installation. If you do not reach the pulley, and one day it will move from a given position. And it’s good if the engine simply loses traction, and does not hit the valves with a piston that did not close in time, driving them into the cylinder head.
For engines with variable valve timing, the camshafts (at least one) have the ability to shift so that, with sufficient throttle response at the bottom (small phase overlap), they do not lose at the top (the camshafts move “toward each other”, increasing the overlap phase, which at high speeds increases power ). Possible reasons why the machine does not pick up speed is a failure of the VVTi control valve or problems with the phase shifting clutches. We have already discussed this issue, speaking about.
In addition, the filling of the cylinders is tied to the intake and exhaust resistance. It is necessary to manage to clog the air filter so that it loses its capacity, but oil emissions through the crankcase ventilation system, especially if the piston is already worn out and the oil catcher is primitive, are not uncommon. On the VAZ-2106, it is not difficult to make the engine “sip oil” through the crankcase ventilation, and such cases are possible on fresh front-wheel drive cars (2109, 2110, 2114). An oily air filter has a sharp increase in resistance, hence the loss of engine thrust.
The release on carbureted cars and old diesel engines is simple, and it is enough to reduce the flow area so that the engine begins to “choke” on exhaust gases, except perhaps with a powerful blow (when moving over bumps, for example) or a canonical potato - but it is at least immediately noticeable.
If the engine with electronic injection does not pull, then the catalyst falls under suspicion in this case. Overheating, fuel ingress due to malfunctions of the power system can cause sintering of its cells. For diesel engines with particulate filters, soot becomes the main enemy: automatic filter burning on the go is ineffective, and at least forced regeneration must be performed.
Problems with the release easily give themselves away: a muffled engine, on a subsequent attempt to start, throws smoke into the intake, the sound of the engine changes, leaks immediately “crawl out” (the exhaust begins to “cut” to the damaged area).
The motor must not only receive the right amount of air and fuel - it must ignite in time. A gasoline engine needs an appropriate ignition timing, a diesel engine needs an injection timing. Since there is no separate ignition system on modern injection engines, ignition timing problems are primarily characteristic of carburetor machines and old injection systems with a distributor (the Japanese used such systems right up to the early 2000s). Check the basic advance angle, set by the distributor, and the operation of the advance automatics in it (in case of malfunctions, the angle that is normal at idle will begin to “leave” when revving).
A separate case is motors where the distributor is driven by a separate pulley from the timing belt (old Audis and Volkswagens). Here, when replacing the belt, the distributor pulley is set “as it should be” (there are no marks on this pulley!), Forgetting that the distributor must be oriented with a cam at the risk on the crankcase under it when replacing the belt. After such a replacement, the car stops driving, as the ignition angles change. For diesel engines with a mechanical injection pump, the initial injection angle is set, in addition, the advance regulator works - they are checked according to the data from the repair and maintenance instructions.
On gasoline engines, we also add spark plugs to the suspects: even if the engine runs normally at idle, it is not a fact that the spark plugs will work well under load, when the pressure in the cylinders at the end of the compression stroke increases and the conditions for sparking become worse. It is worth putting another kit for testing: without an oscilloscope that allows you to take voltage curves from a working ignition system, it is difficult to determine how a candle really behaves under load. In the illustration below, look at the peak voltages corresponding to the moment of sparking: in the third cylinder, the gap is excessively increased, the spark flares up at too much voltage, and its duration drops (the power accumulated in the ignition coil is not enough for normal spark burning).
If we talk about compression, then under normal conditions it decreases as it wears so slowly that the decrease in power occurs imperceptibly for the driver. An exception is rapidly developing breakdowns (cracks in piston rings, destruction of partitions between rings,). Simultaneously with the drop in power, the stability of idling will drop sharply, the final diagnosis will be unambiguously made by a compression gauge.
As for turbocharged engines, the state of the turbocharger is reflected well in their dynamics. An ideal centrifugal pump (turbocharger impeller) has a quadratic dependence of performance on speed: as soon as the speed drops by half, the boost pressure will drop by four. Wedging of the rotor due to destruction or coking of the bearings, burning of the “hot” impeller is the probable reason why the turbocharged machine does not pull. Here, as with compression, a pressure gauge will help out.
Causes of power loss in a carburetor engine
Here it is worth immediately checking the fuel level and the operation of the fuel pump: “underfilling” the fuel immediately betrays itself under load with a loss in dynamics, shooting through the carburetor. Overfilling due to a faulty carburetor locking needle will in the same way lead to a loss of power by the engine, here black smoke and firing from the muffler will become a characteristic feature.
The dynamics of the car is perceived better during acceleration, so a defect in the accelerator pump can also become a possible cause of the “stupidity” of the car. The fact is that all carburetor systems are designed to work in static modes, while the mixture becomes leaner when the speed is set. An accelerator pump serves to combat this over-depletion: when you press the gas pedal, the diaphragm pushes a dose of gasoline through the shut-off valve into the atomizers that go into the diffusers. If the diaphragm of the accelerator pump is broken or the sprayers are clogged, the acceleration of the car will immediately deteriorate so much that it is hard not to notice. It is not difficult to check the accelerator pump - after removing the air filter or the “turtle” from the carburetor, you need to sharply press the throttle actuator: your fingers will feel resistance (the diaphragm will create pressure in the accelerator pump), and gasoline streams should hit the inlet from the atomizers.
In operating modes, the composition of the air-fuel mixture is set statically by a set of fuel and air jets. It is worth blowing them out, and in case of noticeable deposits, rinse with a cleaner: even if this is not the problem, it will not be superfluous to maintain the health of the main dosing system.
Does not pull injection engine
Why doesn't the car pull when the injection systems are feedback-capable and can self-adjust in a "closed loop"? Alas, the possibilities of self-regulation are not as wide as we would like.
The first enemy of injection systems is insufficient fuel pressure. When the fuel consumption is minimal, then the correction margin is enough for idling. But one has only to put a load on the engine, as the correction will jump to the limit threshold, but the nozzles will still “underfill”.
The pressure in the fuel rail is set by three nodes: the fuel pump itself, the pressure regulator and a set of filters (coarse and fine cleaning). The performance of a serviceable fuel pump is several times greater than the needs of the engine at maximum flow - this is done so that the wear of the pump affects the operation of the engine as little as possible. Therefore, a fuel pressure regulator is used, which dumps "excess" fuel either immediately at the pump outlet or from the fuel rail after the fine filter.
In the first case, the fuel rail is called drainless (16-valve VAZ engines, modern foreign cars), in the second - drain. The difference between these systems is in the location of the regulator and in its operation. On the drain ramps, the pressure regulators are controlled by a vacuum in the intake manifold, the pressure in the rail varies depending on the load (at normal 3 bar for VAZ at idle, it is 2.3-2.4 bar, take this into account when diagnosing!). On drainless, the pressure is maintained constant relative to the atmosphere and, depending on the model of the car, is 3.5-4 bar. An exception is direct injection systems, where the operating pressure ranges from 20 to 70 bar.
Something else useful for you:
The resistance of the fuel filters does not affect when measuring the fuel pressure “in the plug” (the pump is forced to turn on with the engine turned off when there is no fuel flow in the rail) and is minimal at idle. But on the other hand, under load, an excessive increase in the resistance of the filters reduces the fuel supply to the rail, which will lead to a loss of speed. Therefore, measure the pressure at idle and under load (for example, by hanging the drive axle and braking the wheels in gear). In cases where idling is normal, and the problems are on the go, it is pointless to measure pressure only at idle (XX).
Check exception steps:
- Remove the coarse filter (“mesh” at the inlet). For a number of machines, this is a well-known problem - for example, on the second generation of Focuses.
- Replace fine filter.
- Measure pressure under load.
- On engines with a drain rail, pinch or otherwise shut off the return line to eliminate the influence of the fuel pressure regulator. On engines with a drainless ramp, the RTD is installed in the fuel pump module, here it is easier to temporarily install a plug washer made of polyethylene or other material that is not destroyed by gasoline under it.
- Measure the pressure again: if it has increased, then the RTD needs to be replaced, otherwise the pump needs to be replaced.
The second reason for "underfilling" is. Even with normal filter operation, deposit formation on atomizers is inevitable over time. It is possible to evaluate in “home” conditions only the shape of the spray jet by removing the ramp and turning the motor with a starter (Attention! This procedure is a fire hazard!). A clean nozzle should “dust” evenly, and not give separate streams or pour to the side. It is possible to evaluate the performance of injectors and compare it with the nominal one only at the stand.
The loss of dynamics is a consequence of excessive enrichment of the mixture. The fuel pressure regulator cannot be blamed here (pump performance, even when operating without an RTD, is not so high that the correction margin of the injection ECU does not block enrichment). It is much more likely that the injectors are leaking (again, it is checked at the stand) or the failure of the sensors that are used to calculate the injection time.
Here, the undisputed leader is the mass air flow sensor - an accurate but sensitive device. As the DMRV becomes dirty and aging, it overestimates the readings, the car begins to consume significantly more fuel. As a result, the over-enrichment of the mixture can no longer be corrected for. But such a malfunction is immediately visible: the car will begin to smoke, the candles will become overgrown with black soot. On motors with an absolute pressure sensor, the air temperature sensor is more likely to fail (here it is a separate unit, while it is built-in in the DMRV).
On cars with an electronic throttle, it is worth checking the operation of the servo by removing the nozzle from the throttle and giving it a gas flow. The throttle should open evenly, without pauses and wedging, indicating problems with the drive gearbox or (the axis, acquiring soot, wedging in the housing).
Video: Lost power. Loss of power
Seal
Sometimes drivers say: the engine pulls poorly, the car does not develop maximum speed. Where to look for reasons? There may be several of them:
- strong overheating of the engine;
- faulty ignition system: the ignition setting is broken (ignition too early or too late); there was a jamming of the centrifugal ignition timing controller; a malfunction has occurred in the vacuum ignition timing regulator;
- insufficient filling of the cylinders with the working mixture;
- interruptions in the operation of the engine;
- loss of compression in the cylinders;
- entry into the cylinders of a lean working mixture.
If the engine does not develop full power, then
it is best to check the ignition system. Note that if the ignition is too late, the engine loses throttle response and overheats. A significant reduction in power occurs due to the fact that the mixture does not have time to burn out at the moment when the piston is in. m. t. The combustion of the mixture continues when the piston moves down, it is easy to determine by touching the exhaust manifold with your hand. It will be too hot, as some of the mixture burns out when released. Too early ignition also has a harmful effect on the operation of the engine, when the combustible mixture ignites prematurely and the force of the gases acts towards the piston, which moves towards the engine. m. t. At the same time, frequent and ringing metallic knocks are heard in the engine, the engine is prone to fuel detonation, does not work well at low speeds, and sometimes gives back blows when starting with the handle.
After establishing that power is being lost due to too early or too late ignition, adjust it. If the ignition timing adjustment fails to achieve the desired results, therefore, there are malfunctions in the automatic ignition timing devices; centrifugal or vacuum regulators.
It must be remembered that the centrifugal regulator regulates the ignition timing only depending on the engine speed. It usually starts at 400-600 rpm of the engine. If malfunctions occur in the centrifugal regulator (weakening of the springs or sticking of the weights), this will lead to a violation of the ignition timing. When the regulator weights are stuck, the ignition timing at both low and high speeds will remain the same. Meanwhile, for high speeds, the ignition timing should be earlier.
Late ignition at high speeds will cause a decrease in power and increase fuel consumption. If the regulator springs are weakened and the weights disperse completely, then even at low speeds there will be a large ignition advance, which will also lead to excessive fuel consumption and a decrease in power. Usually, the serviceability of the centrifugal regulator is checked using a synchronograph.
But, as a rule, there are no devices on the way. Nevertheless, the action of the centrifugal governor can still be checked. How it's done? Without removing the distributor from the engine, you need to remove the breaker lever and turn the cam by hand in the direction of rotation of the roller until it stops. The weights disperse. Release the cam, and it will return to its original position under the action of the spring forces of the weights. If jamming is detected, then it is necessary to eliminate it, and replace the weakened springs with new ones.
From what has been said, it is clear that the centrifugal regulator regulates the ignition moment only depending on the number of revolutions. But on the way, the car has to move along different roads - flat and with ups and downs. Suppose that when driving at a constant speed both on a flat road and on a hilly road, the centrifugal regulator will give only the same ignition advance. While the engine load and throttle opening are significantly greater when driving on an uphill road, the ignition advance should be less than on a flat road when driving at the same speed. The ignition timing is controlled by a vacuum regulator when the throttle opening (engine load) changes. It may have the following faults:
- loss of elasticity of the spring;
- air suction into the plane of the spring;
- jamming of the ball bearing of the breaker panel.
When the vacuum regulator spring is weakened, the ignition timing increases at low and medium loads. If, however, air is sucked into the cavity where the spring is located (if the diaphragm is damaged), then the ignition timing will decrease at low loads. If there is too much air suction, the vacuum regulator does not work at all. The vacuum regulator may also fail due to the ball bearing of the breaker panel seizing.
Like a centrifugal, a vacuum regulator is usually checked for serviceability using a synchronograph. On the way, you can check it in the simplest way: shake the breaker panel on the bearing and make sure there is no excessive clearance, and also determine if there is an increase in the gap between the panel pin and the diaphragm rod, if the rod itself jumps off.
If, however, a vacuum is created in the vacuum regulator tube disconnected from the carburetor, then, if it is in good condition, the breaker panel should turn in the opposite direction of the cam rotation. Having found that both advance angle regulators are in good order and the ignition is set correctly, the reason for the decrease in power must be sought in insufficient filling of the cylinders with the working mixture. This can be caused by a sticky throttle on the axle (not fully opening it). It is necessary to check the throttle actuator and, if necessary, eliminate jamming, clean the axle. Then make sure the air filter is working. If it is dirty, disassemble, wash and, if necessary, change the oil. It is advisable to check the serviceability of the valves and springs of the gas distribution mechanism; in case of violation of the gaps or breakage (loss of elasticity) of the valve springs, weak and broken springs should be replaced, the gap should be adjusted.
Insufficient filling of the cylinders with the working mixture can occur when the needle valve of the float chamber sticks, a faulty muffler, the use of the wrong brand of fuel, as well as in the case of a large deposit of tar and coke in the intake pipe.
A common cause of incomplete engine power is a lean mixture entering the cylinders. Reasons for the formation of a lean mixture:
- jets and channels in the carburetor are clogged, contamination (freezing of water) of the fuel lines in the power system has occurred. Rinse and blow jets and channels, blow dirty fuel pipes, and if necessary, clean them with wire;
- sticking of the fuel pump valves or clogging of the sump screen, a small breakthrough of the diaphragm. First, eliminate the jamming of the fuel pump valves, rinse the filter element and the mesh, and replace the torn diaphragm with a new one or restore the old diaphragm in the manner described earlier;
- air leakage at the junction of the carburetor parts, the carburetor flange with the intake pipe, the intake pipe flanges with the cylinder block due to loosening of the fasteners, as well as damage to the gaskets. You can find the place of suction with a match or soap suds. The flame of a match brought to the supposed place of suction is deflected towards the gap, and a window is formed in the soap foam. Air leakage is eliminated by tightening nuts or bolts, as well as replacing the corresponding seals;
- wear of the fuel pump drive lever, clogging of the air holes in the fuel tank filler cap, jamming of the air damper. These defects are eliminated as follows: the defective parts of the fuel pump are replaced with new ones, the air holes of the plug are cleaned, the length of the air damper control cable is checked and, if necessary, adjusted. Relatively often, the cause of a decrease in engine power is a drop in compression in the cylinders.
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Why is the engine not picking up the speed that is necessary for correct operation? This is a question many drivers ask themselves. During the operation of engines of various types, they often encounter a situation where, when you press the gas pedal, the engine does not react in any way and does not gain the necessary speed.
Often such problems occur with cars equipped with LPG, although when switching to gasoline, the problem disappears. Malfunctions of a different plan can entail both fairly serious repairs and simple preventive measures. Let us consider in more detail why the engine is gaining momentum poorly, both on gasoline and diesel fuel.
In the first case, it is very important to try to analyze under what conditions this happened and how it manifests itself. Be sure to try to identify all the accompanying symptoms.
The failure of a fully functional internal combustion engine to gain the necessary speed after service work or repair is usually the result of incorrect assembly, connection errors, etc. such situations allow you to instantly identify malfunctions by inspecting or returning the car to the repair station.
Possible reasons why the engine does not develop speed are conditionally divided into categories. First, let's deal with simpler, one might say minor malfunctions. The set of necessary indicators when driving is very dependent on the usefulness of combustion, the composition of the mixture, the efficiency of supplying it in the right volume and timely ignition.
One of the common reasons why the speed cannot be gained to the desired value is the disrupted operation of the ignition, fuel and air supply systems:
- Significantly clogged air filters reduce the ability for air to pass through the filters. The engine in such a situation starts to work unevenly, loses power, as a result of which it will not be able to gain momentum. One of the common reasons is the appearance of branches, dirt, bags, etc. in the air filter;
- You need to pay attention to the suction for the intake of excess air. The problem may arise unexpectedly, or as a result of gradual progress. Working on a strong suction, the motor is very difficult to gain momentum. The proportions of fuel and air in the fuel-air mixture deviate significantly from the normal value. The resulting mixture is very lean for gasoline and rich in air. An engine with such a mixture starts without problems, but will not run smoothly and will not be able to pick up speed at the slightest movement;
- The unit is not receiving enough fuel. Usually, the culprit is a filter, which can easily become clogged with foreign objects. Usually there are no problems with starting the internal combustion engine, since the fuel level is normal, but the car twitches, does not respond in time to manipulations with the gas pedal. Turnovers may not reach the level of a certain tachometer mark;
- A dirty filter mesh on the fuel pump, since over time the formation of plaque on it from the tank is a natural process. The lack of the required pressure in the system leads to a drop in pump performance. Normal operation of the motor is impossible in different modes: the engine will pick up, it needs speed and immediately stall due to clogging of the mesh;
- Disrupted operation of wires and candles makes ignition of the combustible mixture problematic. The process of ignition of the fuel charge is untimely, the power drops, respectively, the speed will not increase. The cause of these manifestations is usually pollution and oiling of candles, damage to its body, gaps during installation on the electrodes;
- Trouble of the engine due to breaks in high-voltage wires, misfiring of the ignition moment, worsened dynamics of the set of internal combustion engines revolutions.
Serious malfunctions that require a certain level of skill, knowledge and special equipment or a visit to a workshop. It will no longer be about consumables, but about the details:
- Perhaps the most important reason is the disturbed phases of the timing. The balanced operation of the gas distribution mechanism is disrupted due to the untimely opening of the valves. Such troubles usually appear after unsuccessful attempts to replace the timing belt, especially when jumping teeth. Also, the causes include valves that are incorrectly adjusted, malfunctions in the valve timing, and even a breakdown of the timing drive;
- Disrupted operation of the incendiary module and coils. Misfiring becomes commonplace, and the engine simply cannot reach the speed necessary for normal operation;
- It is worth paying special attention to the power supply of the injectors on the injector. The control signal does not act on the nozzle, or it occurs intermittently due to incorrect wiring;
- Violations in the operation of the gasoline pump, and if the diesel engine, then the injection pump. The problem develops gradually, it all starts due to a gradual weakening of the ability to pump fuel, and as a result - a lack of pressure. As a result, when the engine is heavily loaded, it will start to stall more and more often;
- The problem of injector contamination occurs when units operate with extremely poor quality fuel. Be sure to clean the nozzles at least 30 thousand;
- Incorrect operation of the sensors of the electrical system can even affect the composition of the combustible mixture.
What is the result?
Given all the problems with the fact that the internal combustion engine is slowly gaining momentum, it would be advisable to conduct a diagnostic check for errors as soon as possible. As a matter of urgency, such a procedure must be carried out in the case when the “check” on the tidy lights up.
Rarely, there are cases when the engine does not develop speed due to the failure of the computer. Such troubles can arise due to engine washing and careless diagnostic maintenance of the firmware.
The result of such an intervention is an inadequate perception of the ECU speed: low are taken for high, and vice versa. The maximum power of the internal combustion engine can be obtained provided that all routine maintenance provided by the manufacturer and other equally important service activities are carried out in a timely manner.
During the operation of the car, many owners face a number of problems. One of them is a decrease in engine power. At the same time, it is not always clear what is the reason for this phenomenon, what measures to take, whether it is worth going to the service station. Let's talk about the main reasons why the engine does not pull and how you can fix the problem on your own.
The main reasons for reducing engine power
1. Malfunction of the crankshaft position sensor
There are situations when the DKPV does not send a control command to supply the air-fuel mixture in a timely manner. As a result, the power of the power unit drops before our eyes. The main reason for the failure is the shift of the gear star in relation to the pulley and the bundle of the damper. In such a situation, it is necessary to carefully inspect the damper and replace it.
2. Increase (decrease) the gap between the electrodes of the candles
During operation, due to the powerful temperature effect, the distance between the electrodes of the spark plug may decrease or increase. To exclude or confirm your suspicion, you need to check the size of the gaps with a round feeler gauge. If the distance is less or more than the allowable, you need to adjust by bending the side of the electrode or replace the spark plug. As for the optimal distance of the spark gap, it can be different (depending on the type of candle) - 0.7-1.0 mm.
3. The appearance of soot on candles is another clear sign of a problem.
If the engine does not pull well, it is necessary to unscrew all the spark plugs one by one and inspect them. If obvious carbon deposits appear on the electrodes, the device must be cleaned with a brush with a metal bristle. It is important not only to clean the candles or replace them, but also to find out the cause of this phenomenon.
4. Failure of spark plugs
Reduced engine power may be caused by product failure. In this case, it is necessary to check the performance of the candle on a special stand. If the suspicions are confirmed, then the only way out is to replace the set or one candle.
5. There is no gas in the tank
You can diagnose the problem by looking at the fuel gauge. If it is faulty or there is a suspicion of its “inadequacy”, then the presence of fuel can be determined by removing the fuel pump.
6. Contamination of the fuel filter, freezing of water in the system, pinching of the fuel wire, failure of the fuel pump
All these malfunctions can be safely attributed to one category, because they all have the same symptoms - the starter cranks the engine, but there is no smell of fuel from the exhaust pipe. If the car is carbureted, then the cause must be sought in the float chamber. Most likely it is not getting fuel. In the case of an injector, the presence of fuel in the rail is easier to check by pressing a special spool (installed at the end of the rail).
To correct the problem, it is necessary to warm up the engine thoroughly and bleed the power system with a tire pump. After that, all the pipes of the system, hoses and the fuel pump itself are changed.
7. The fuel pump creates too little pressure
Such a problem can only be determined by special measurements (made directly at the outlet of the fuel pump). After that, the quality of the fuel pump filter is checked.
The solution is to clean the fuel pump filter, replace it (if repair is not possible) or install a new fuel pump.
8. Poor contact quality in the circuit
Poor quality of the contact in the circuit through which the fuel pump is powered or the failure of its relay. The first thing to do to check is to make sure the quality of the "ground" on the car and take resistance measurements with a multimeter. If the resistance level is really high, then the only way out is to strip the contact groups, crimp the terminals well or install a relay (if the old one is faulty).
9. Broken nozzles or malfunction in the supply system
If there is a suspicion of failure of these elements, it is necessary to check the resistance of the windings with a multimeter for the fact of an open circuit or an interturn circuit. If the cause of the problem is a malfunction of the computer, then such a check can be carried out exclusively at the service station.
There are several ways to eliminate the decrease in engine power for this reason (depending on the depth of the problem) - install a new computer, clean all nozzles, ensure high-quality contact in the electrical circuit, and so on.
10. Breakdown of the DPKV
Breakage of DPKV - crankshaft position sensor or damage to its circuit. In such a situation, the check engine malfunction lamp lights up. The first thing to do is to inspect the integrity of the DCPV itself, make sure that the gap between the ring gear and the sensor is normal (it should be about one millimeter). The normal resistance of the sensor coil is about 600-700 ohms.
To solve the problem, it is enough to restore normal contact in the electrical circuit and install a new sensor (if the old one turned out to be faulty).
11. Out of order DTOZH
DTOZH - a sensor that controls the temperature of the coolant is out of order. Symptoms of a malfunction are as follows - the engine malfunction lamp lights up. If there is a break, then the electric fan of the system begins to rotate continuously. In addition, it is necessary to check the health of the sensor itself.
If the engine power has dropped for this reason, then it is necessary to restore the quality of the contact in the electrical circuit and install a new sensor.
12. Out of order TPS
The TPS is out of order - a sensor that controls the correct position of the throttle valve (or its chain). As in previous cases, the “Check engine” lamp lights up here. If there is an open in the TPS circuit, then the engine speed usually does not drop below one and a half thousand revolutions.
The solution to the problem is to clean the throttle assembly and restore the quality of the contact connection in the entire electrical circuit. If the sensor is defective and cannot be repaired, it must be replaced.
13. Out of order DMRV
The DMRV, a sensor responsible for controlling mass fuel consumption, failed. Here, the optimal action is to check the integrity of the DMRV or replace it with a serviceable device. If the failure of the DMRV is confirmed, then it is necessary to make an attempt to clean it, and if it is impossible to repair, simply replace it.
14. Breakage of the knock sensor
Detonation sensor failure. With such a malfunction, the engine malfunction lamp necessarily lights up on the instrument panel. In addition, when DD detonation fails, there is no detonation in any of the operating modes of the power unit and the engine power also drops. With such a problem, the best option is to restore the integrity of the contact group in the electrical circuit and install a new sensor.
15. Failure of the oxygen sensor
Failure of the oxygen sensor or a violation of its circuit. Such a malfunction is characterized by the ignition of the "Check engine" lamp. In this case, the first thing to do is to check the heating coil for integrity. Firstly, the resistance is measured, and secondly, the voltage level at the output. Measurement can be done even without breaking the circuit - just pierce the insulation with needles.
To eliminate the malfunction, it is worth repairing the oxygen sensor, restoring the quality of the wiring and cleaning all the holes through which air is sucked in. In extreme cases, it is necessary to replace the oxygen sensor itself.
16. Depressurization of the exhaust system
Diagnosing such a problem is simple - just inspect the main elements while the engine is running at medium speeds. To solve the problem, it is necessary to replace the exhaust manifold gasket and stretch all the seals.
17. Computer failure
Failure of the electronic control unit (ECU). Despite its reliability, the ECU can also break down (sometimes its software just gets lost). To make sure that the computer is working (failure of the computer), you need to check the voltage on the unit itself (the normal parameter is about 12 Volts) or replace it with a known-good unit. If the control unit is defective, it may need to be replaced. In some cases, it is enough to change only the wiring.
18. Violation of the adjustment of clearances in the valve drive
You can make sure that the parameters match only by checking with special probes. If the gaps do not correspond to the norm (written in the manual), then adjustments must be made.
19. Deformation or breakage of the springs on the valves
In this case, you will have to remove the cylinder head and measure the length of the springs under load and in a free state. If broken or deformed springs were found, then they need to be changed.
20. Worn camshaft lobes
Here it will be enough to visually inspect (after removing the necessary elements) and replace the camshaft if necessary.
21. Disordered valve timing
In such cases, it is necessary to check the fact that the marks on the camshaft and crankshaft coincide. If there is an “imbalance”, then it is enough to set the correct position using special marks.
22. Low cylinder compression
Low compression in all or some cylinders. Causes include likely valve damage or wear, broken or sticky piston rings. To verify the suspicions or refute them, it is enough to make the necessary measurements. If the suspicion is confirmed, then it is necessary to repair the power unit - change the rings, pistons or repair the cylinders.
ConclusionThe above list is only a part of the malfunctions, due to which the engine power drops. But in most cases, this is enough to diagnose the problem, fix it, and return much-needed traction to your “iron horse”.