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With long-term operation of the car, sooner or later the time comes when the driver begins to notice that the car "pulls" worse and worse. To put it another way, the motor does not cope well even with small loads. To overcome them, you have to spin the crankshaft almost to maximum speed. Other signs also appear: sluggish acceleration from a standstill, difficulties in gaining speed when overtaking, etc. In this case, there may be an increased smoke of the exhaust, but there are no extraneous noise under the hood when the power plant is operating - it works smoothly and calmly. So what happened, why doesn't the car pull?

When the motor pulls poorly uphill ...

Causes of power loss common to all types of motors

If there are no other signs of deterioration in engine performance, except for loss of thrust, it is worth conducting a comprehensive check, which consists in testing the power unit by the "elimination method".

Low-quality fuel

In about 50% of cases, the “culprit” of the loss of thrust is the fuel. Due to its poor quality or unsuitable octane number (RON), the engine does not develop power.

You can determine that the fuel in the car's tank is unsuitable by a number of signs:

1. The engine started getting worse.
2. Detonation appeared. This symptom is most pronounced when fuel with the required octane number has been diluted with gasoline with a lower RON.
3. When inspecting spark plugs turned out of the cylinder block (BC), you can see carbon black or reddish (brick) uncharacteristic for serviceable parts, which indicates the presence of unnecessary impurities. The first option indicates that gasoline does not burn completely, the second confirms the presence of additives containing metal.
4. Inefficiently working candles. This can be determined with a sharp increase in speed, when the engine has no room for further acceleration. The candles can be clogged due to low-quality fuel or simply worn out.

It is not difficult to solve the problem: low-quality fuel should be drained and the tank filled with a suitable fuel with the required RON. Clean the candles of carbon deposits, and if their service life has come to an end, replace them with new ones, all at once, in a set from one manufacturer. If carbon deposits appear, you will again have to deal with diagnostics of the cylinder-piston group (CPG) and (or) the fuel system.

It's better to refuel at proven gas stations

Dirty air and fuel filters

If the first of them is clogged and does not allow air to pass through well, the mixture will be too rich, that is, there will be a lot of fuel in it, which will stop burning completely. As a result, the engine thrust will drop. If the fuel filter is dirty, the result in terms of the operation of the power unit will be the same, with the only difference that the mixture will become very lean, since there will be little gasoline in it. Premature contamination of the air filter can be caused by the operation of the machine in dusty conditions, and the fuel filter can be caused by poor fuel quality.

Violation of valve timing

The main parts of the gas distribution mechanism (timing) are intake and exhaust valves. They are "obliged" to open and close only at the right time, so that the fuel mixture enters the cylinders on time, and the exhaust gases are removed. This process is called phase distribution. If you violate it, you will see that the engine power has disappeared, which will start to "triple", and sometimes start poorly.

The reasons for the violation of the valve timing:

• wear, as well as improper installation, displacement of the chain or timing belt (most often this is a jump by one tooth (link));
• play or deformation of the pulley on the crankshaft;
• wear of hydraulic lifters, camshaft and (or) its bed;
• burnout or rupture of the BC head gasket;
• malfunction of the camshaft position sensor (DPRV).

To restore normal operation of the timing, it is necessary to set the position of the timing shafts and the crankshaft according to the marks. If the chain is worn out, replace it. The same applies to the camshaft with bed, hydraulic lifters, gasket and DPRV.

Exhaust system resistance

Many consider the only task of the exhaust system to muffle loud sounds and remove exhaust gases. However, in modern cars, a catalyst is installed to reduce the level of emissions of harmful substances. When this element is heavily contaminated or destroyed, the passage of gases is impeded. As a result, the motor works "like a strangled one."

In Russia, the problem is solved by the elementary removal of the catalyst. However, it must be remembered that in some car models such an operation will require changes in the electronics (programming).

Catalyst removal

Violation of ignition timing

It is about the moment of ignition of the combustible mixture. It is it that determines the ignition timing (UOZ). When it deviates towards an increase, the mixture ignites early, towards a decrease - late. Both options lead to improper engine operation, incomplete combustion of the mixture, which can be accompanied by popping in the muffler. On injection engines VAZ 2110, 211, 212, 214, 215 (there is also a classic with an injector, for example, VAZ 2107) UOZ is set automatically, on carburetor VAZ 2101-2106, 07, 08, 09 (the last two models can be with an injector) it must be installed manually.

Signs of a violation of the UOZ:

• difficult engine start;
• increased fuel and oil consumption;
• drop in throttle response and power of the power unit;
• unstable operation of the internal combustion engine at idle;
• the car responds poorly when you press the gas pedal.

Adjusting the UOZ on an injection engine

Everything here is controlled by electronics. First you need to make sure that it is working properly and that the throttle sensor is working. At idle, it should be slightly open by about 1% (if this is not the case, adjust the mechanical drive), the normal voltage on its contacts is 0.45-0.55 V (the auto's bot network should give out 13-14.3 V). With a sharp press on the gas pedal, the damper should open 90 ", and the voltage on the sensor should rise to 4.5 V. If this is not the case, you need to adjust the damper drive and check the sensor's serviceability (TPS).

To do this:

• take the tester and put it in the voltage measurement position;
• disconnect the connector from the sensor - you will see three contacts - one goes to ground, the other to the computer (which one is connected to, determine according to the diagram);
• start the engine and check the supply voltage - it should be about 5 V;
• turn off the engine and switch the tester to resistance measurement mode;
• with the damper closed, between the ground and the contact going to the computer, the device should show 0.8-1.2 kΩ;
• when the damper is open, the resistance is 2.3-2.7 kOhm.

If the obtained data does not correspond to the above parameters, the sensor must be replaced. If this does not work, you should check the computer.

Exposing UOZ on carburetor engines

The simplest and most effective way is to use a regular 12-volt light bulb.

Algorithm of actions:

1. Turn the crankshaft pulley until the marks coincide (on the cover - this is the central risk) using a special spanner wrench. If not, turn on 4th speed and push the car until the marks match.
2. Disconnect the thin wire going to the coil from the ignition switch (distributor) and connect a light bulb to it, the second contact of which is shorted to ground.
3. Loosen the nut that secures the distributor (usually it is a “13” wrench).
4. Turn on the ignition, make sure that the lamp is on, and slowly rotate the distributor around its axis until it goes out.
5. Now turn the distributor again until the light bulb flashes, and immediately tighten the distributor mounting nut.

Malfunctioning spark plugs

The planned replacement of these elements of the ignition system is carried out after 20-30 thousand km of run. If the candles are platinum, the resource increases to 100 thousand km. However, the situation when candles (most often one of them) fail ahead of schedule is not uncommon.

You can see and hear this by a number of signs:

• the engine starts with difficulty, especially in winter;
• idling is unstable, the tachometer needle jumps, the motor may stop periodically;
• when the power unit is operating, there is increased vibration, for example, the gearshift lever is shaking;
• weak acceleration dynamics - the car does not develop its full power, "dulls";
• when you press the accelerator, "dips" are noticeable;
• fuel consumption has increased.

When one spark plug does not work, experienced drivers say that the engine is "troit", that is, out of 4 cylinders, only 3 work.

To find a faulty part, you need to:

• wear dielectric rubber gloves;
• with the engine running, disconnect the high-voltage wire from each candle one by one;
• in this case, the nature of the operation of the motor should change, the revolutions should drop, but if this did not happen, then the cylinder does not work - the candle does not form a spark.

It is worth finding out the reason for the poor performance of the part, it is quite possible that it is defective. If later other candles begin to fail, you will have to look for the reason elsewhere - the CPG or the fuel system.

Reduced compression

Often, the reasons for the loss of engine power can be associated with trivial wear and tear of the power unit. Do not forget that a car at the age of about 100 thousand kilometers begins to lose its power by 10-15%. If you think that the loss is excessive, you need to check the compression. Its nominal value is indicated in the documentation for the machine. For testing, you will need an inexpensive device - a compression gauge, which is a pressure gauge attached to a hollow tube or connected to a rubber hose equipped with a tip. It is screwed into the cylinder block instead of a spark plug. Next, disconnect the high-voltage wire from the ignition coil. Crank the crankshaft with the starter and read the highest compression gauge reading. The operation should be repeated for each cylinder.

Compression check

A pressure lower than that specified in the instructions by more than 15% indicates worn out rings, pistons, cylinder block walls, valves. To solve the problem, you can bore the BC to the overhaul size, replace the piston rings, grind (or replace) the valves.

Automatic transmission malfunctions

One of the tasks of the gearbox is to transfer torque to the wheels. And if this process is disrupted, then the engine does not pick up speed. You hit the gas and the acceleration is sluggish. The whole thing may be in the slipping of the automatic transmission.

There are several reasons for this:

• poor quality or not what the manufacturer recommends the gear oil;
• clogged filters;
• clogged valve body channels;
• faulty solenoids (in this case, slipping is observed "hot");
• friction clutch wear (maximum service life 200-300 thousand km);
• problem with the control unit.

Most of the above malfunctions in a garage are difficult to fix. Therefore, you will have to use the services of a specialized technical station.

If the carburetor engine does not pull

A carburetor is a mechanical device for preparing a combustible mixture of fuel and air. If in this mechanism the proportions of the components are violated, then the engine does not pull.

You need to adjust the carburetor in stages:

1. Jets. Check their calibration - the part supplying air must have a larger diameter than the one through which the fuel enters.
2. Throttle valve. When you press the gas, it should open completely (if it is not, adjust the actuator).
3. Ignition system. Its contact version was considered above. To check the contactless system, turn on the ignition and look at the dashboard voltmeter - its arrow will go to "12", and in a second it will rise higher. If there is no voltmeter, install a known working switch and check the operation of the ignition system again.

Regular carburetor

Why is there a loss of power in the injection engine

The peculiarity of this motor is a gas pump that works like an electric motor. If it does not work properly, the engine speed will be unstable in all ranges. That is, the fuel will be supplied unevenly, which will lead to a drop in the power of the power unit. The pump may not perform well due to a dirty filter - it must be checked and, if necessary, cleaned. Another reason for the loss of power of the injection engine is the ineffective operation of the injectors, which become dirty during operation. It is necessary to carry out diagnostics using a special (you can even make a homemade) stand and clean the parts or replace them with new ones. The next reason is the incorrect operation of the electronics. These can be sensors or the ECU itself. In the latter case, it is recommended to install a serviceable unit or go to a service station.

If you have any questions - leave them in the comments below the article. We or our visitors will be happy to answer them.

Cars VAZ-2114, from the beginning of production, are equipped with eight-valve engines with a volume of 1.5 liters. Since 2007, they have been equipped with an eight-valve 1.6 liter engine with an environmental class Euro-4. The operation of the car, sometimes not correct, over time presents "surprises". not at full power, the thrust is reduced. Let's try to understand the reasons and methods of elimination.

The dynamics of the car, first of all, depends on the stable and stable operation of the engine. When the indicators of this characteristic decrease, this indicates that there are problems in the operation of the engine.

VAZ-2114 engine

Unstable engine operation is caused by the following:

• The fuel filter is dirty.
• The diaphragm of the fuel pump is clogged.
• Do not work or.
• Insufficient.
• The on-board computer is malfunctioning.
• The nozzles are clogged (you need to clean them or).
• The clutch disc is worn out.
• Malfunctions of sensors that control: the position of the crankshaft; coolant temperature; ; detonation.

These are just some of the possible reasons why the engine can pull poorly throughout the rpm range.

It is worth mentioning the fuel pump, which fails. The real state of affairs is determined by detailed diagnostics.

A brief analysis of the causes and their consequences for the VAZ-2114

1. Fine filter contamination ... Determined visually. Debris particles present in the fuel tank, gasoline accumulate in the filter, the channels are clogged. Insufficient fuel supply. "Treatment" - .

   Changing the fuel filter

2. The diaphragm of the fuel pump is clogged ... The reason is the same, there are dirt particles in the gasoline. Solved by excavation, flushing, blowing with compressed air

   We change the grid of the fuel pump

3. Clogged air filter ... For a short time, it is solved by blowing the filter, you can knock on a solid object. Ideally, the filter is replaced with a new one.

   We clean or change the air filter

4. Candles do not work or work poorly ... Determined by inspection, after unscrewing. One of the reasons - . The gaps are checked with a feeler gauge, the necessary one is installed. For this, the side electrode is bent to the required value.

   Checking the gap between the spark plug electrodes

5. Formed. The electrodes are cleaned with sandpaper (zero), cleaned, and the gap is checked.

   Cleaning spark plugs from carbon deposits

6. The serviceability of the spark plugs is checked on a stationary stand. If problems occur, need to be replaced.

   Candles are best checked at a stand in a car service

7. Insufficient compression in the cylinders ... This defect appears as a result of high wear of the cylinder-piston group. The result is increased oil consumption, incomplete combustion of the combustible mixture, and gasoline enters the crankcase. In some cases, it is sufficient to replace the piston rings, in others, an overhaul of the engine is required.

   We measure the compression in each cylinder

8. Failure or breakdown of the electronic control unit ... It is impossible to repair without special knowledge. Diagnostics is carried out with special devices. A flashing is possible, or the control unit changes completely.

   We carry out diagnostics of the control unit

9. Clogged nozzles ... ... There are additives in fuel, but they do not give much effect. Replacement may be required, so read the resource: ““.

   You can clean the nozzles at home.

10. The clutch disc is worn out ... In motion, with an increase in revolutions, the car does not pick up the required speed, slipping is felt. Expertly checked by starting off in fourth gear. If it stalls, everything is in order with the disk, if the engine is running, then there are problems. Solved by replacing the clutch disc.

    Illumination of the Check engine sensor indicates a malfunction of the sensors

conclusions

Maintenance (MOT), which should be carried out according to the manufacturer's recommendations, will avoid many problems. The only question is where to go, at the "kulibins", or at specialized service stations, equipped with the necessary equipment and apparatus. The choice remains with the vehicle owner. The sooner the prerequisites for the failure of a particular part are revealed, the less financial losses in the future.... It should be remembered that timely maintenance increases the safe operation of the vehicle.

Sufficient engine power is a prerequisite for normal vehicle operation. But what to do when the diesel engine does not pull, although not "Multi-colored" smoke? Nothing - stop by our service center rather. But first, find out the possible theoretical reasons for this phenomenon, so as not to suspect the mechanics of "auto-cheating" costing extra money.

What is needed for a diesel engine to work "in full"

More often than not, even when there is no white, black or blue smoke, the motor does not reach its full power. This happens sometimes due to a decrease in the permeability of the coarse fuel filter in the tank of the machine, and a decrease in the permeability of the fine fuel filter. Of course, most motorists are in awe of their car and therefore, having driven exactly as much as indicated by the manufacturer, they rush to change the filters in good faith.

But often automakers cannot even assume that water or dirt can be present in such an amount in diesel fuel.

Therefore, the first and foremost rule: if you want the engine to pull “to the fullest”, change the fuel filter after at least half of the mileage specified by the manufacturer.

This is especially true when refueling somewhere far from large cities. However, you can visit us, and we will help not only with repair of fuel injection pump or other units, but we also modernize the fuel system, making it less vulnerable to our fuel.

To make sure that the reason for the loss of power by a diesel engine is low-quality fuel, you need to replace the factory opaque fuel pipes connecting the injection pump with the fuel filter to a transparent auto hose. After replacing the hose and fuel filter, be sure to bleed the fuel system to remove excess air.

After completing all these requirements, start the engine. If the fuel filter is clogged, you will see air bubbles circulating in the transparent hose. By increasing the speed of the diesel engine, the number of bubbles will visually increase significantly.

Air bubbles in the fuel system cause the engine to malfunction (engine “troit”). At the same time, there is a loss of power.

What to do when the motor "troit" only at high revs

If at medium and idle speeds you have no complaints about the operation of the diesel engine, and when switching to high speeds, the engine starts to "triple" (which, of course, does not allow it to work at the rated power), then you should think about:

• malfunctions of the engine gas distribution mechanism (timing);
• turbocharger malfunctions;
• loss of patency of the fuel filter (when it is literally clogged with dirt).

To find the specific cause, again, start with the fine fuel filter - it may be time to replace it. Disconnect the fuel hose from the filter fitting and lower it into a can of clean diesel fuel.

Now start the engine, and if it runs at any speed like a clock, then the reason for the instability was just a dirty fine fuel filter. So it’s time to replace it. If the malfunction persists, try again to clean the coarse filter from dirt. And bleed the fuel system again.

If, after additional cleaning of the filters, the engine stubbornly runs at speeds above average, then check the compression. It can decrease as a result of a violation of the functionality of the valve mechanism, including due to a malfunction of the hydraulic lifters (when one of them is jammed due to dirty oil) and the cylinder-piston group.

In a word, there are plenty of reasons for the motor not operating at full power. And in order to make the right (and the lowest in price) decision, it is easier and cheaper to call into our auto center, in order to forget once and for all that your diesel engine does not "pull". So do not put off until tomorrow what should have been done the day before yesterday - repair of injectors or engine diagnostics.

Many have at least once had to deal with a situation when a motor that worked perfectly before is "blown away", the machine seems to grow an anchor from behind. The reasons why the engine does not pull and does not pick up speed are different, but it is not difficult to recognize the signs of most without the skills of an automobile diagnostician or minder.

Common causes for all engines

The characteristics of the motor indicated in the passport data of the car are provided under certain conditions. This is the normal filling of the cylinders with air, which is the working fluid in the internal combustion engine. This is the ability to heat it up to the desired temperature in time - to supply a certain amount of fuel of proper quality and ignite it on time (the pressure peak for maximum efficiency should occur at the moment the piston crosses top dead center).

ICE working cycle

The loss of engine power, regardless of its design, is the result of a number of general 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 the mixture specified by the carburetor settings may deviate from the ideal, and the burning rate of the mixture changes. So, if problems appeared immediately after refueling, you yourself know which way to look.

The filling of the cylinders with air is rigidly connected with the valve timing. It is enough to leave the marks, as the strokes of the internal combustion engine will be displaced: a difference of 1 tooth can significantly reduce the engine power. Moreover, it is not necessary for the belt or chains 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 piston on the valves that did not close in time, driving them into the cylinder head.

In 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 on the top (the camshafts are displaced "towards each other", increasing the overlap phase, which increases power at high speeds ). Possible reasons why the car does not pick up speed are a failure of the VVTi control valve or problems with the phase shifter couplings. We have already dealt with this question, speaking of.

In addition, cylinder filling is tied to intake and exhaust resistance. To clog the air filter so that it loses its throughput - this must be contrived, but oil emissions through the crankcase ventilation system, especially if the piston filter is already worn out, and the oil trap is primitive, are not uncommon. On the VAZ-2106, it is not difficult to make the engine "sip on oil" through the crankcase ventilation, and even on fresh front-wheel drive cars (2109, 2110, 2114), such cases are possible. The resistance of an oily air filter rises sharply, hence the loss of engine thrust.

The release on carburetor cars and old diesel engines is simple, and it is quite possible to reduce the flow cross-section so that the engine begins to "choke" with exhaust gases, perhaps with a powerful blow (when moving over irregularities, 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, the ingress of fuel due to malfunctions in the power system can cause sintering of its honeycomb. For diesel engines with particulate filters, soot becomes the main enemy: automatic filter burning on the go is ineffective, and at least a forced regeneration must be performed.

Problems with the release easily betray themselves: a muffled engine, upon a subsequent attempt to start, throws smoke into the intake, the sound of the engine changes, leaks immediately "crawl out" (the exhaust begins to "whip" to the damaged area).

The engine must not only get the right amount of air and fuel - it must ignite on time. On a gasoline engine, an appropriate ignition timing is needed, on a diesel engine - an injection timing. Since there is no separate ignition system on modern injection engines, problems with ignition advance 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 automatic devices in it (in case of malfunctions, the angle, normal at idle speed, will start to "go away" when accelerating).

A separate case is motors, where the distributor is driven by a separate pulley from the timing belt (old Audi and Volkswagens). Here, when replacing the belt, the distributor pulley is set "as necessary" (there are no marks on this pulley!), Forgetting that when replacing the belt, the distributor must be oriented with a cam according to the risk on the crankcase under it. After such a replacement, the car stops driving, since 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 rises and the conditions for sparking become worse. It is worth putting another kit for the test: without an oscilloscope, which allows you to take the voltage curves from a working ignition system, it is difficult to determine how the plug actually behaves under load. In the illustration below, look at the peak voltages corresponding to the moment of sparking: the gap in the third cylinder is excessively increased, the spark ignites at too high a voltage, and its duration decreases (the power accumulated in the ignition coil is not enough for normal spark combustion).

If we talk about compression, then under normal conditions it decreases with wear so slowly that the decrease in power is imperceptible for the driver. An exception is rapidly developing breakdowns (piston ring cracks, destruction of partitions between rings,). Simultaneously with the drop in power, the idling stability will sharply drop, the final diagnosis will be made unambiguously by the compressometer.

As for turbocharged engines, the state of the turbocharger is reflected well on their dynamics. An ideal centrifugal pump (turbocharger impeller) has a quadratic dependence of performance on rpm: as soon as rpm drops by half, the boost pressure drops by four. Rotor wedging due to destruction or coking of bearings, burning of a "hot" impeller is a likely reason why a turbocharged machine does not pull. Here, as with compression, a pressure gauge will help out.

Reasons for the loss of power in a carburetor motor

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, shots into the carburetor. Overfilling due to a faulty locking needle of the carburetor will likewise lead to a loss of power by the engine, here black smoke and firing from the muffler will already become a characteristic sign.

The dynamics of the car is perceived better during acceleration, so that a possible reason for the "dullness" of the car can be a defect in the accelerator pump. The fact is that all carburetor systems are designed to work in static modes, while the mixture is over-depleted when speeding up. To combat this overpopulation, an accelerating pump is used: when you press the gas pedal, the diaphragm pushes a dose of gasoline through the shut-off valve into the nozzles that go into the diffusers. If the diaphragm of the accelerating pump ruptures or the spray nozzles are clogged, the acceleration of the machine will immediately deteriorate so much that it is difficult not to notice. It is not difficult to check the accelerating pump - after removing the air filter or "turtle" from the carburetor, you need to sharply press the throttle actuator: fingers will feel resistance (the diaphragm will create pressure in the accelerating pump), and trickles of gasoline should hit the inlet from the nozzles.

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 the injection engine

Why doesn't the car pull when the injection systems are equipped with feedback and can self-adjust in a “closed loop”? Alas, the possibilities for 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, the correction reserve is sufficient for idling. But as soon as the engine is loaded, the correction will jump to the maximum threshold, but the injectors will still "underfill".

The pressure in the fuel rail is set by three units: the fuel pump itself, the pressure regulator and a set of filters (coarse and fine). The performance of a serviceable fuel pump several times exceeds the needs of the engine at maximum flow - this is done so that pump wear is as little as possible affecting the operation of the engine. Therefore, a fuel pressure regulator is used, which discharges "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 the vacuum in the intake manifold, the pressure in the ramp changes depending on the load (at normal 3 bar for a VAZ at idle speed, it is 2.3-2.4 bar, take this into account when diagnosing!). On the drainless ones, the pressure is kept constant relative to the atmosphere and is, depending on the car model, 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 forcibly switched on on the muffled engine 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 filter resistance reduces fuel supply to the rail, which will lead to a loss of speed. Therefore, measure the pressure at idle speed and under load (for example, hanging the drive axle and braking the wheels in a gear). In cases where idle speed is normal, and problems occur on the fly, it is meaningless to measure pressure only at idle speed (XX).

Checking exclusion stages:

1. Remove the coarse filter (mesh at the inlet). This is a known problem for a number of cars - for example, on the second generation of "Focuses".
2. Replace fine filter.
3. Measure pressure under load.
4. On engines with a drain ramp, pinch or otherwise muffle the return line to exclude the influence of the fuel pressure regulator. On motors 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.
5. Measure the pressure again: if it has increased, then the RTD needs to be replaced, otherwise, the pump must be replaced.

The second reason is "underfilling" -. Even with normal filter operation, the formation of deposits on the nozzles is inevitable over time. Only the shape of the spray torch can be assessed at home, by removing the ramp and turning the motor with a starter (Attention! This procedure is fire hazardous!). A clean nozzle should "dust" evenly, and not spurt 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 the excessive enrichment of the mixture. The fuel pressure regulator cannot be blamed here (the pump performance, even when operating without an RTD, is not so high that the correction margin of the injection computer does not block the enrichment). It is much more likely that the injectors are leaking (again, it is checked at the stand) or the failure of the sensors on which the calculation of the injection time is tied.

Here the undisputed leader - the mass air flow sensor - is an accurate but sensitive device. As the mass air flow sensor becomes dirty and aging, the readings are overestimated, the car begins to consume significantly more fuel. As a result, the over-enrichment of the mixture can no longer be corrected by. But such a malfunction is immediately visible: the car will start to smoke, the candles will become overgrown with black carbon deposits. On motors with an absolute pressure sensor, the air temperature sensor is more likely to fail (here it is a separate unit, while in the mass air flow sensor it is built-in).

On cars with an electronic throttle, it is worth checking the operation of the servo by removing the nozzle from the throttle and letting it go through. The throttle should open evenly, without pauses and wedging, indicating problems with the drive gearbox or (the axle, overgrown with carbon deposits, wedges in the housing).

Video: Lost power. Loss of power

Seal

During the operation of the car, many owners are faced with 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 the decrease in engine power

1. Malfunction of the crankshaft position sensor

There are situations when the DKPV untimely sends a control command to supply the air-fuel mixture. As a result, the power of the power unit drops before our eyes. The main cause of the failure is the shift of the toothed star in relation to the pulley and the damper delamination. 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 candle may decrease or increase. To exclude or confirm your suspicion, you need to check the size of the gaps with a round probe. 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 spark plug) - 0.7-1.0 mm.

3. The appearance of carbon deposits on candles is another clear sign of a problem.

If the engine pulls poorly, 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 metal bristle brush. In this case, 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

Decrease in 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 were confirmed, then the only way out is to replace the kit or one candle.

5. There is no gasoline 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 line, failure of the fuel pump

All these malfunctions can be safely attributed to the same 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 looked for in the float chamber. Most likely, it is not supplied with fuel. In the case of an injector, the presence of fuel in the ramp is easier to check by pressing a special spool (installed at the end of the ramp).

To fix the problem, you need to thoroughly warm up the engine and pump the power system with a tire pump. After that, all the pipes of the system, hoses and the gas pump itself are changed.

7. Fuel pump creates too little pressure

This problem can be determined exclusively 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 impossible) or install a new fuel pump.

8. Poor quality of contact in the circuit

Poor quality of contact in the circuit through which the fuel pump is powered or failure of its relay. The first thing to do to check is to make sure the quality of the "mass" on the car and measure the resistance with a multimeter. If the resistance level is really too high, then the only way out is to clean the contact groups, crimp the terminals well, or install a relay (if the old one is faulty).

9. Breakage of 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 or interturn short circuit. If the cause of the problem is a malfunction of the computer, then such a check can be carried out exclusively at a 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 the nozzles, ensure high-quality contact in the electrical circuit, and so on.

10. Breakdown of DPKV

Breakage of DPKV - crankshaft position sensor or damage to its chain. In such a situation, the "Check engine" malfunction lamp comes on. The first thing to do is to inspect the integrity of the DKPV itself, to make sure that the gap between the gear ring 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. DTOZH is out of order

DTOZH is out of order - a sensor that controls the temperature of the coolant. The symptoms of the malfunction are as follows - the engine malfunction lamp comes on. If there is a break, then the electric fan of the system begins to rotate continuously. In addition, it is necessary to check the serviceability 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. Failed TPS

The DPDZ is out of order - a sensor that controls the correct position of the throttle valve (or its chain). As in the previous cases, the "Check engine" lamp comes on here. If there is an open circuit in the DPDZ 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, then it must be replaced.

13. The DMRV is out of order

The DMRV is out of order - the sensor responsible for monitoring the mass fuel consumption. Here, the optimal action is to check the integrity of the mass air flow sensor or replace it with a serviceable device. If the failure of the mass air flow sensor is confirmed, then it is necessary to make an attempt to clean it, and if it is impossible to repair it, simply replace it.

14. Breakage of the knock sensor

Damage to the knock sensor. In the event of such a malfunction, the engine malfunction lamp must light up on the instrument panel. In addition, in the event of detonation DD failure, there is no detonation in any of the operating modes of the power unit and the engine power also decreases. 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. Breakage of the oxygen sensor

Breakage of the oxygen sensor or violation of its circuit. Such a malfunction is characterized by the "Check engine" lamp lighting up. In this case, the first thing to do is to check the integrity of the heating coil. First, the resistance is measured, and second, 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

It is easy to diagnose such a problem - it is enough to 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. Failure of the ECU

Failure of the electronic control unit (ECU). Despite its reliability, the ECU can also break down (sometimes its software simply gets lost). To make sure that it is working properly (failure of the computer), it is necessary to check the voltage on the unit itself (the normal parameter is about 12 Volts) or replace it with a known working unit. If the control unit is found to be defective, then it may need to be replaced. In some cases, it is sufficient to change only the wiring.

18. Violation of clearance adjustment in the valve drive

The compliance of the parameters can only be verified by checking with special probes. If the clearances are not correct (written in the manual), then adjustments must be made.

19. Deformation or breakage of valve springs

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. Camshaft cams are worn out

Here, a visual inspection will be enough (after removing the necessary elements) and replacing the camshaft, if necessary.

21. The valve timing is broken

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 establish the correct position according to special marks.

22. Low level of compression in the cylinders

Low compression level in all or some of the cylinders. The reasons include probable valve damage or wear, breakage or sticking of piston rings. To be convinced of suspicions or to 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 rings, pistons or repair the cylinders.

Output

The above is only a part of the malfunctions due to which the engine power decreases. But in most cases, this is enough to diagnose the problem, fix it, and return much-needed traction to your "iron horse".