Self-diagnosis: causes of low engine power

Poor maintenance can result in reduced engine power.

Low engine power usually means that your engine lacks power during acceleration, or that your engine is suddenly unable to reach normal road speed. While low engine power may mean that normal wear and tear is gradually taking away a significant amount of your vehicle's power, this guide is about abnormal power loss - a failure caused by a system or component not working properly due to malfunction or lack of adequate maintenance.

A low engine power condition can be caused by one or more of a long list of components that need attention. Luckily, you can narrow the list down a bit, knowing that some of the most common causes of engine power loss are related to the fuel delivery, ignition, or emission system.

Whether you're dealing with a defective part or a lack of proper maintenance, the tests and strategies below will help you get your engine back on track. The tests refer to various systems, specific faults and conditions known to reduce engine power. Finally, you are reminded of some important diagnostics that may apply to your particular case. Each component or condition mentioned includes a "Things You Can Do" section so that you can take some action when you deem it necessary.

Systems that can cause low engine power

We will consider the systems in order:

1. Ignition system
2. Fuel system
3. Exhaust system
4. computer system
5. Vacuum leaks
6. Gearbox or clutch
7. Exhaust system
8. Compression

But first, I'm going to list some very basic checks you should make before you start testing.

Four Checks You Should Do

Here are some important but simple checks to consider first.

1. If you notice right after some work has been done on your car, make sure everything is plugged back in. Check for loose hoses, disconnected electrical connectors, and loose bolts, and if fluids have been changed, see if the correct engine or transmission oil has been used.
2. . With insufficient pressure, your tires will wear out faster, and the car will consume more fuel to accelerate the car. Check the tire pressure with a pressure gauge when the tires are cold. Inflate tires 1-3 psi. An inch below the maximum pressure indicated on the tire sidewalls.
3. Even (CEL) did not ignite. You may have some pending code that will help you determine the cause of the problem. A faulty sensor or actuator can cause the vehicle computer (or transmission) to receive incorrect voltage signals, causing the computer to change the air-fuel mixture and rob your engine (or transmission) of power. Whatever codes you find, always check the circuit or components listed in the DTC. It is possible that a bug can make the computer "think" of a failure in another circuit or component. On some vehicle models, a faulty camshaft position (CMP) sensor can cause a sudden loss of engine power - the computer will likely set a code if it detects a problem with this sensor.
4. Many GM vehicle models are equipped with a low engine power warning light (REP), similar to the check engine light (CEL). When this indicator (or both indicators) turns on, you will notice that the engine barely responds to the accelerator. It is a scary situation if the problem occurs while driving on the highway or in heavy traffic. The most common triggers for this warning light are the harness connecting the throttle position sensor (TPS) or the TPS itself. Other problems that may cause the REP light to come on are related to the throttle body (including wiring), oxygen sensor, accelerator pedal position sensor (or wiring harness), or.

Testing eight systems that can cause low engine power

Now here are eight systems that typically contribute to lower power consumption and how you can test them yourself.

Worn or dirty plugs slow down the engine

Ignition system

Sluggish engine behavior can very often be traced back to worn or faulty parts in the ignition system. Several components in the system need maintenance at regular intervals. For example, spark plugs and spark plug wires, but you should also check the ignition coil and ignition timing. If any of these components cause you to not get a good spark, the engine will not develop its full power.

What can you do: When you feel that the engine is not pulling, one of the first checks should be to check the strength of the spark. Use an adjustable spark tester (Thexton is an acceptable brand) to check spark quality. Check for 40 kV and 30 kV. If your spark can't cross that gap at these settings, you may have worn wires, a weak or faulty distributor, a bad ignition coil, or a bad ignition control module, depending on your particular module. Check follow-up tests and refer to your vehicle repair manual for proper diagnosis for your specific model. If you don't have a manufacturer's service manual, I highly recommend getting an aftermarket service manual for your exact model.

When visually inspecting ignition system components such as distributor cap, rotor, ignition coil, look for traces of carbon, carbon buildup and damage (oxidation). Carbon traces are like little lines that form around these components. They can cut off the voltage passing through the system, depriving the spark plugs of the necessary voltage to produce a good spark. Replace them if necessary.

After checking the spark strength, if necessary, check the following individual system components.

Spark plug

Spark plugs can become contaminated with carbon deposits (soot) and other chemical by-products, especially if the vehicle is not serviced according to the suggested schedule.

Dirty spark plugs cannot produce enough spark to ignite the air-fuel mixture. In addition, with a long mileage, the gap between the spark contact electrodes will increase due to wear.

What can you do: Perform a visual inspection of the spark plugs, check the gap between the electrodes with a feeler gauge and adjust if necessary. Your vehicle repair or repair manual has the appropriate spark plug gap. Your service manual can help you analyze your spark plugs, which can tell you a lot about the condition of your engine.

Just like spark plugs, spark plug wires wear out and after many miles they can prevent the spark from reaching the spark plugs.

What can you do: Check the resistance of each wire with a digital multimeter (DMM) and compare your reading to the specifications in your repair manual. Typically you need about 5000 ohms per foot of wire. Otherwise, replace them with a good quality cable set.

Ignition coil

The ignition coil generates the high voltage necessary for a spark to jump between the electrodes of the spark plug. This voltage is typically between 4,000 and 30,000 volts, depending on the specific car model.

Ignition coils also wear out or fail, resulting in a weak spark, an intermittent spark, or no spark at all.

What can you do: You can check the ignition coil(s) in your car with a digital multimeter using your car repair manual.

Ignition time

Ignition timing refers to the relationship between the spark and the position of the piston in the cylinder during the power stroke.

The ignition timing must be correct for proper combustion of the air-fuel mixture. When the ignition is delayed, you may notice an increase in fuel consumption, a decrease in engine power and poor acceleration.

Timing problems can be caused by a worn (excessively stretched) or damaged timing belt or chain. Even 2 or 3 degrees of difference from the correct time can lead to problems with engine operation.

On most modern cars, ignition timing cannot be adjusted directly, but you should still be able to check the timing yourself. On older models, you can check and adjust the time yourself.

What can you do: Check ignition timing using time indicator and tachometer. If your ignition system uses a distributor, you can adjust the timing yourself if necessary. Consult your vehicle's repair manual. Your manual may also list the service interval for the belt or chain.

A clogged air filter will reduce engine power.

Fuel system

Although modern fuel injection systems may have different configurations, they all share many common components such as fuel injectors, control modules and sensors. Any of these components can fail and cause your engine to lose power.

The fuel system can give you just as much trouble as the ignition system. When the engine is not pulling, there are some details that you should check.

The engine stops pulling, the reason is probably in the fuel filter

Over time, the fuel filter becomes clogged, reducing fuel consumption and preventing the engine from accelerating properly or resulting in a loss of engine power.

What can you do: Check your vehicle owner's manual or repair manual for a fuel filter maintenance schedule. Even if your filter isn't the root cause of the problem, replacing the filter at the manufacturer's recommended interval will take the load off the fuel pump and extend its life.

The engine does not develop full power, check the air filter

When the engine is running, the air filter in the air cleaning system traps dirt, dust and other foreign particles and removes them from the airflow entering the engine. Eventually, the filter becomes clogged. And a heavily clogged air filter will make your engine work much harder. You will notice this in the form of such an effect as the engine pulls poorly or the engine power has dropped sharply.

What can you do: Most car manufacturers recommend every 12 months. Therefore, be sure to check the air filter and replace it if necessary. Consult your vehicle's owner's manual or repair manual.

Poor engine thrust check fuel injectors

The most common problem with fuel injectors leading to a loss of engine power is clogging. But they can also fail.

What can you do:

• On throttle body injectors (TBI), you can check the injector's fuel atomization pattern by removing the cap from the air filter housing. Fuel atomization should be even and partial atomization, following an inverted V-pattern. You can add a fuel additive to clear a slightly clogged injector or take it to your shop for service. However, if the internal valve in the nozzle has failed, and not just clogged, you will need to replace it.
• In a multi-port fuel injection system, dirty or clogged injectors are harder to detect. Depending on the configuration of your particular system, it may be relatively easy for you to disconnect each of the injectors from their port in order to check their spray pattern. In other systems, disassembly is a more complex process.

If you suspect dirty injectors or have not serviced the injection system for a long time, try adding a fuel additive to the fuel tank. Otherwise, you may have to take your vehicle in for an injector balance test, which measures the amount of fuel each injector sprays when energized.

The engine power has dropped, we are looking for the cause in the throttle valve

Throttle failures are not common, but they do happen.

What can you do: You can quickly check the throttle body to make sure the valve - the throttle plate - is fully open when the accelerator pedal is fully depressed.

• Remove the air ducts or air filter box cover to gain access to the throttle body.
• Have an assistant fully depress the accelerator pedal with the engine off.
• Make sure the throttle responds appropriately to the pedal.
• If not, adjust or fix throttle linkage or remove carbon deposits from valve and throttle bore. The buildup can also prevent the valve from working properly.

The engine does not develop power. Check the fuel pressure regulator.

A faulty fuel pressure regulator can allow too much fuel into the engine, or too little, which can result in poor engine traction.

What can you do: Check the fuel pressure with a pressure gauge. The check may indicate problems with the fuel pump (low pressure or low volume), a clogged fuel filter, or a faulty fuel pressure regulator.

The exact procedure may vary from one engine model to another, but the general steps are the same:

• Locate the Schrader valve on the fuel rail (this is a test fitting similar to the air valve on your tires). If your model does not come with this valve, you can still connect the sensor directly to the fuel line using adapters (see repair manual).
• Then follow the steps in the repair or service manual and compare readings to specification.

A faulty EGR valve can reduce engine power.

The engine does not pull the reason in the exhaust system

Another possible, though not common, cause of engine power loss during acceleration is a faulty exhaust gas recirculation (EGR) valve.

The EGR valve allows the measured amount of exhaust gases at higher engine idle to re-enter the engine to reduce engine heat and emissions.

When the EGR valve fails, it can get stuck open or closed. If the valve is sticking (or intermittently sticking), opening or not working properly, the most common symptoms you will notice are rough idle and dips during acceleration, but in other cases you will simply notice a lack of engine power when you press the accelerator.

What can you do: You can test the EGR valve at home using a hand held vacuum pump.

computer system

As part of the computer system, both the manifold absolute pressure (MAP) sensor and the manifold air flow (MAF) sensor affect the air-fuel mixture controlled by the computer. Typically, the car computer stores a fault code in memory when a fault is detected using any of the sensors.

What can you do: even if the Check Engine light is off, it is a good idea to scan your computer for pending trouble codes. The most common problem with MAF sensors is a dirty sensor element. You can clean it with an electronic contact cleaner or MAF cleaner. Whether your car is equipped with a MAP or MAF sensor, you can check it at home. Consult your vehicle's repair manual.

Vacuum leaks can affect engine power.

Vacuum leaks or why engine power is lost

A leak can be due to a loose, damaged, or broken vacuum hose, a blown gasket, or a damaged throttle body gasket.

What can you do: A common technique for detecting a vacuum leak is to use a rubber hose:

• Start the engine and let it idle.
• Using a rubber hose, put one end of the hose over your ear and the other end to listen to various vacuum hoses.
• Trace the hoses with your diagnostic hose
• Check around the edge of the intake manifold and the throttle body gaskets.

A leaking vacuum hose or gasket will make a hissing sound and you can hear it with the rubber hose. Just be careful with moving engine parts when troubleshooting vacuum hoses.

Gearbox or clutch

If you have an automatic transmission and haven't checked your transmission fluid lately, now is the time to do so. If you have a manual transmission, the clutch may be slipping.

A common symptom of low or contaminated automatic transmission oil is slippage. Your engine is running but your car is not moving. Power is not being transferred to the wheels, giving the impression that your engine lacks power. The same thing can happen in a car with a manual transmission, when the clutch is worn out, the force does not reach the wheels.

What you can do (automatic and manual):

Automatic transmission:

• Check the gear oil after the engine has reached operating temperature (drive or idle for 20 minutes or more).
• Stop the engine and leave it for three or five minutes.
• Then pull the transmission oil dipstick.
• Use a rag to wipe the tip of the dipstick with oil.
• Fully insert the dipstick into its tube and pull the dipstick out again.
• Let the dipstick stay horizontal on the cloth.
• The oil level should be between the ADD and FULL marks towards the end of the dipstick. Otherwise, add the required amount of the recommended fluid for your vehicle model.
• Check fluid. It should have a clear reddish color. If the color is opaque and brownish or black, or has a burnt smell, replace it. Consult your vehicle's owner's manual or repair manual.

Manual Transmission:

• Park in a safe place away from traffic and people
• Install emergency brake
• Start the engine
• Set the gear to high gear
• Slowly fully release the clutch pedal for two seconds (so as not to burn the clutch disc or flywheel) and depress the clutch pedal again
• If the clutch is good, the engine should stall or stop as soon as you release the clutch.
• If the clutch is bad, your engine will continue to run normally.

Usually water and acid are the most common enemies of a car exhaust system. But pollution, system overheating, and high mileage can lead to airflow restriction.

The most common victim of an exhaust system limitation is. In addition to failing or breaking down during normal wear, internal catalytic components can melt due to overheating and fouling.

Once the catalytic converter shuts off, you will notice a reduction in engine performance and, depending on the type of failure, a strong smell of rotten eggs escaping through the exhaust pipe.

But the problems may not stop there.

What can you do:

Check your exhaust system for high back pressure.

Temperature test:

• After driving for about 15 minutes, park the car in the garage and turn off the engine.
• Raise the vehicle and secure it on jack stands.
• Using a kitchen thermometer, measure the temperature of the inlet pipe at the catalytic converter (be careful, the temperature can exceed 1400F).
• Take a reading of the exhaust pipe temperature at the catalytic converter.
• A clear difference in temperature indicates a connected transmitter.

Rattle Test:
Depending on the type of converter installed and the type of failure, if the catalytic elements inside the converter are broken, the converter will rattle when struck with a rubber mallet.

Pressure test:

• Remove the oxygen sensor in front of the converter.
• Install the pressure gauge in the threaded hole.
• Start the engine.
• Take pressure readings at idle and at higher speeds.
• The high pressure reading indicates a connected transducer or muffler.
• Disable the muffler and repeat the test to find the obstruction.

Vacuum test:

• Connect a vacuum gauge to the vacuum hose going to the brake booster.
• At idle, open and close the throttle valve, allowing the engine to reach about 2500 rpm.
• You should see the gauge needle go down to almost zero, should return to the previous reading of about 5 inches of mercury (in inches of mercury) and return to the previous reading. If the needle returns too slowly to the previous reading, you may have a faulty exhaust system.

Worn cylinders or rings will reduce engine compression.

Compression

Poor acceleration can also be the cause of engine compression problems. These problems are inevitable on high mileage engines or those with a history of poor maintenance. And as miles accumulate, more engine power is lost due to wear on cylinders, rings, and pistons, and carbon buildup around valves. Rebuilding an engine can be necessary and expensive.

Lock throttle valve in open position.

Disable the ignition system and fuel system (with electronic fuel injection).

Connect a pressure gauge to one of the spark plug holes.

And crank the engine through about six compression strokes.

Repeat the test on the remaining cylinders.

Then compare the needle movement characteristics and pressure readings with specifications.

Your vehicle repair manual can help you pass this test.

Final Thoughts

You can avoid many low power problems and many more by following a proper regular maintenance schedule. The ignition system and fuel system are often the main culprits when the engine does not run, but a number of components in other systems can also cause the same problem. This guide will help you find the source of the problem, fix it, and save money.

Categories:// dated 08.08.2019

Probably, any driver has encountered such a problem when the car has lost its former dynamics: it accelerates for a long time, and when lifting it completely refuses to move in higher gears. In this article, we will tell you in detail what to do if the VAZ engine does not pull or pulls poorly, we will consider the main causes and troubleshooting methods.

Conventionally, all types of gasoline engines can be divided into gasoline and injection. In general, their principle of operation is exactly the same, but the factors that affect engine power become different. Consider the problem of carburetor and injection engines separately.

Does not pull the carburetor engine VAZ

A carburetor is a mechanical device designed to mix air and gasoline, with the further supply of this mixture into the combustion chamber of the engine. Problems with a lack of engine power on a carburetor are quite common and there are a lot of reasons for them. We will try to deal with each.

• Engine power system

First of all, the loss of engine power can be hidden behind the power system. As a rule, the engine does not pull due to a lack or excess of fuel. The fact is that gasoline and air are mixed in a certain ratio. And if one or another element is missing, then the motor will start to work unstably and stop developing the required power.

The ratio of air to fuel should be within 15 to 1. If the amount of gasoline exceeds the allowable parameters, then it will not burn out completely, which means it will reduce the throttle response of the engine. In addition, such a change in ratios will seriously increase fuel consumption and further lead to other engine malfunctions.

Insufficient amount of fuel and does lead to "starvation". The ignition of the air-fuel mixture will be insufficient and the piston will move slowly. All this is achieved by the correct setting of the carburetor, the exact selection of jets and many other factors.

It starts with the selection of jets. An important condition is the presence of a larger jet for air than a jet for gasoline. Then the float chamber of the carburetor is adjusted, which should only be half filled with gasoline. After that, the car engine starts and the quantity and quality of fuel are adjusted in accordance with the technical literature for this carburetor model. If, at the same time, a stable speed is reached in the range of 800-900 rpm, then the carburetor tuning was successful.

Another link in the power system is the presence of clean air and fuel filters. If the filters are too dirty, then the fuel or air will pass with great difficulty, which also violates the composition of the mixture. Thus, the filters must always be kept clean.

Check also. It is possible that it does not open completely. In this case, stop the engine and adjust the throttle position.

It is also possible that the fuel pump has stopped creating the required pressure. To do this, you need to remove it and check it. It is possible that it will have to change the drive and its diaphragm. There is another very common malfunction - increased wear of the fuel pump rod. This means that it pumps perfectly manually, and when the engine is started, it works for a short time, then it loses power and the engine stalls.

• valve assembly

The gas distribution mechanism also plays an important role in maintaining engine power. If the valves, in the process of wear, have lost their tightness, then gases will break through from the combustion chamber directly into the valve mechanism. All this reduces the pressure created in the engine cylinders, so the pistons move noticeably slower.

To restore the tightness of the valves, it is necessary to grind them and properly adjust them. The essence of the adjustment is to set thermal gaps in their impact mechanism. The size of the gaps is indicated in the reference literature for the car engine.

In addition, the valve train must work in synchronization with the engine crankshaft. If the opening and closing of the valves does not correspond to the position of the piston, then the engine will not only pull badly, but may not start at all.

• Ignition system

Perhaps the decisive factor. Sparking should occur only in strictly specified cycles, otherwise the motor will not only pull badly, but it can also overheat and work very, very unstable. If the adjustment of the UOZ was successful, and the engine still does not pull, and at idle it is completely unstable, then it makes sense to check the ignition system as a whole.

On a non-contact ignition system, you need to make sure that the switch is working. To do this, turn on the ignition and follow the position of the voltmeter needle: at first it should deviate to 12 Volts, and after a second it should rise even higher. If the Voltmeter is not provided by the design of your car, then replace the switch with a known-good one and check the operation of the ignition again.

First of all, pay attention to the cleanliness and tightness of the contacts in the distributor. If everything is in order, you can move on. Start the engine and pull out the high voltage wires one by one. After each wire, listen to how the motor works. If it starts to work even worse, then there is a spark in this cylinder. If the operation of the engine has not changed, then this means that you have found a faulty spark plug or high-voltage cable. This assumption can be verified by replacing the element with a known good one.

Improper use of spark plugs also affects engine performance. Most often, the difference between the candles lies in the gaps between the electrodes. The gap size must correspond to the engine, the season of operation of the car and the model of the candle.

Check the ignition distributor. It is possible that a resistor in the rotor circuit burned out in it. Another problem is the loose fit of the contact carbon. Try replacing it or the spring.

The last ignition problem is the fuzzy operation of the octane corrector. In the absence of the required vacuum, the special plate does not return to its original position. In addition, there is increased backlash in the system. Eliminate it and replace all defective parts. Check the tightness of the hose.

The last and worst malfunction is this. These elements are designed to reduce the friction of the piston against the walls of the engine cylinder and remove residual oil so that it does not enter the engine combustion chamber.

The failure of the rings entails a violation of the tightness of the combustion chamber, in connection with which the compression of the cylinder is seriously reduced. This can be determined by increased oil consumption and the corresponding color of the exhaust gases. In this case, only a serious engine repair will help.

• Faulty exhaust system

The exhaust part of the car also plays an important role in creating the required pressure in the engine cylinders. If this pressure difference between intake and exhaust is violated, then the engine thrust can be noticeably reduced. In this case, check the contamination of the exhaust system: the pipes must be removed and inspected. Pay special attention to the intake pipe. If there are any holes in it, it will lose its tightness and become unusable.

If there are any extra holes or damage in the resonator, pipes or muffler, they must be replaced without fail.

Bad injection engine

Some of the malfunctions of the carburetor engine can be safely attributed to the malfunctions of the injection engine. This applies to the timing mechanism, filters, ignition system, exhaust and engine piston group.

• Gasoline pump malfunction

The main feature of the injection engine is the presence of an electric gasoline pump. It is an electric motor that creates a vacuum and pumps the fuel system with the required amount of fuel.

Affects the stability of the engine speed. After all, if it works intermittently, then gasoline will be supplied in the appropriate amount. Most often, the electrical wiring, the fuel pump relay or the contact group of the electrical circuit is to blame. In this case, it is necessary to diagnose and repair the faulty fuel pump.

Another problem with the fuel pump is the increased contamination of its filter. Measure the pressure at the outlet and compare it with the normalized values. If the measurement result does not correspond to the reference values, then the fuel pump filter must be cleaned.

• Nozzles (injectors)

A nozzle is a small solenoid valve that at a certain point in time sprays the air-fuel mixture into the combustion chamber of the engine. Engine power also depends on the correct operation of the injectors.

Diagnostics of their serviceability is carried out using a multimeter. To do this, it is necessary to check the resistance of the windings for an open and short circuit. If they are found to be defective, the injectors must be replaced.

• Faulty sensors

Sensors are the main collector of information for the operation of the electronic control unit. In the event of a malfunction of one of the sensors, the controller, without receiving the necessary information, instantly switches the motor into emergency mode with the corresponding lamp on the engine dashboard turning on.

A defective sensor can be calculated by conducting electronic diagnostics at a service station and replaced.

• Malfunction of the computer itself

The electronic control unit can also malfunction. To check its performance, it is necessary to replace it with a known good one and check the operation of the engine. The voltage supplied to the unit must be 12 volts.

Video - The engine does not pull at low speeds, the car does not go uphill

Modern engines are distinguished by good power, a sufficient level of efficiency, and less pollute the environment. When the behavior of the power unit changes, it is immediately noticeable. If the car does not pull, the reasons for this phenomenon can be very different. Let's take a look at them.

An engine can lose traction for a variety of reasons. There are a huge number of different malfunctions that result in a loss of power. Sometimes cravings disappear without any symptoms. The unit does not make unusual noises for it, does not vibrate - it just lost traction. Every day the car goes worse and worse. Probably, this situation is familiar to every motorist.

Poor fuel quality

If the car does not pull, the reasons for this phenomenon can be very different. But the first is the quality of the fuel.

Try to remember at which gas station you last refueled your car. Maybe the fuel is not of very high quality? Gas stations sometimes sell such gasoline that the engine stops working at all until the tank is empty and better quality fuel is poured into it.

Check the air filter

A filter that is too dirty does not allow enough air to pass through to create a fuel mixture. This can lead to a significant drop and fuel consumption will increase significantly.

In addition, the quality of the materials used in it can also affect the operation of the motor.

When purchasing another filter, many people try to buy the cheapest products that are available. You should not buy anything, because further repair of the motor will cost much more.

There are many different stories about cheap and non-original filters. These products break, and then a series of serious malfunctions follow the chain, up to the failure of the piston rings. To check the condition of the air filter, you need to open the hood, remove the element from the housing and visually assess the condition. If necessary, the part is immediately changed.

Fuel filter

Sometimes, in a certain state, fuel cells do not supply enough fuel to the car. As a result, the car does not pull. The reasons are clear, and in order to check the fuel filter, it is dismantled, and the remaining fuel is drained.

Then it blows out. If the element is clean, then it will blow through very easily. If it is difficult or impossible to blow it out, then it should be thrown away. Otherwise, you will have to change the fuel pump in the future.

Pressure in the power system

The fuel pump is located in the gas tank, on the injection motor. The pump will be found under the hood, on the engine. In most cars, power loss can be associated with the fuel pump.

Many modern cars have special connectors on the fuel line for connecting a pressure gauge. This way you can check the pressure. If the connector is missing, then you will have to work a little to connect.

The pressure values ​​can be found in the engine manual. There is a special regulator in the line, with which you can relieve excess pressure directly into the tank. This regulator may be incorrectly configured, or it may leak. To test it, you need an ordinary air pump. With it, it is necessary to smoothly raise the pressure level to the one indicated in the passport to the motor. If you did not have time to increase the pressure, and the regulator dumped fuel into the tank, then it must be replaced.

Ignition system

Here it is necessary to check whether the ignition timing is set correctly. Sometimes, if the car does not pull, this may be the reason. It is also necessary to check the condition of the candles and high-voltage wiring. For more information on how to perform the check, you can read in the instructions for a particular engine. The main thing here, in troubleshooting, is to use not only your experience. It is also important to analyze similar situations on other vehicles.

Air flow and pressure sensor

These two elements determine how much air the engine consumes, as well as how much air is needed to create the optimal fuel-air mixture. If these sensors are out of order, then the ECU will make incorrect calculations and, accordingly, traction may be lost. If the car does not pull, the reasons (including the VAZ-2110 injector) may be in these sensors. If necessary, they should be replaced, and then the power will return again.

But if the car has an ECU, why then does the corresponding sweetheart on the dashboard not light up? The electronic control unit is programmed for an open or short circuit. If none of these are present, and the sensor simply does not work as it should, the computer will be able to report that the mixture is not being prepared correctly. If the car pulls poorly, there may be other reasons, but the sensor is worth checking. You will have to look for the source of the incorrect operation of the sensor yourself. The parameters of a particular element can be found in the instructions.

Timing belt or chain

The crankshaft and shaft must rotate together and at the same time synchronously. That's what belts are for. Here you just need to combine the marks that are on the chains, belts and gears.

It happens that the belt can jump to another tooth. Chains tend to stretch. However, if these mechanisms are timely and properly serviced, this cause can be ruled out.

Exhaust system check

The device of a modern engine is quite complex. Manufacturers make them so that cars do not pollute the environment. Or if polluted, then minimally.

So, one of the devices that affect the purification of exhaust gases is a catalyst. It can be located in different places. If it is in your car, then regular use of low-quality fuel, which is sold in large quantities at most of our gas stations, the catalyst may become unusable. But it not only collapses, but can also block the normal exit of exhaust gases. As a result, the car does not pull uphill. Causes - including a clogged catalyst.

To check the catalyst, it is necessary to use remote thermometers. You can also check its performance by pressure before and after the device. If all these possibilities are not available, then you will have to dismantle the device and assess its condition visually. If the catalytic converter is clogged, it should be replaced or replaced with a flame arrester.

Compression

If the car does not pull, the reasons may be in the compression. You will need a compression gauge to check. It is better if it is equipped with a pressure gauge with good accuracy. During engine operation, the piston rings wear off. As a result, compression in the cylinders decreases or disappears altogether. If the timing valves are not too tight in their seats, then the test will show poor results.

To identify the cause of poor compression, after the measurement is made, oil is added to the cylinder, and then measured again. If the level has increased slightly, then it is necessary to change the piston rings. If you are unlucky and the compression remains the same, then the valves will go under the replacement. If the car does not pull, the reasons (VAZ-2109 is no exception) may be precisely in this.

Before measuring compression, the battery should be well charged. Otherwise, you will not get the correct indicators. The compression gauge is screwed in instead of candles. This is much better than using a rubber seal. Perhaps, if the car does not pull, the reasons are low compression.

Checking the transmission

Sometimes the power unit can develop serious power, but it does not reach the wheels. If during the ride you hear that the engine is working hard, but you don’t feel the speed, then maybe the automatic transmission system is slipping or there are blockages on the brake side.

To check, you need to drive into a straight section, set the automatic transmission selector to position D, and then see how the car behaves. If the speed decreases, then a diagnosis should be made. If everything is in order with the brakes, you need to go to a good service station and check the automatic transmission.

You can also check the parking brake. To do this, go to the free space. Warm up the car and then apply the handbrake. Next, press the brake pedal, and set to position D. Then press the accelerator. If the engine keeps speed around 2000, then everything is in order with it. If less or more, you should go to the service station to test the automatic transmission.

Why the car does not pull: reasons (carburetor)

If the thrust of such a motor has disappeared, the fuel pump fitting may be dirty or the pressure in the system may be low.

It is also possible that the carburetor is simply dirty or there is some problem with the needle valve. Errors or incorrect settings for adjusting the composition of the fuel mixture are possible. If the carburetor dampers are not open enough, traction may disappear. When the fuel level in the engine drops, the thrust also disappears. When there is any traction problem in the engine, it is urgent to carry out a full diagnosis.

It is imperative to find why the car pulls poorly, we have already considered the reasons. If a malfunction is found, it should be fixed immediately. If you could not find the cause of the decrease in traction yourself, do not hesitate. A deeper examination should be carried out in the service station. But basically, the cause still manages to be identified and eliminated independently.

So, we found out why the car loses traction.

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. Fuel filter contamination, water freezing in the system, fuel wire pinching, fuel pump failure

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.

Output

The 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”.

Often, beginners and not only drivers are interested in why the car does not accelerate and does not pull. As a rule, such a problem is associated with the engine. At the first sign of a malfunction, it is advisable to conduct a detailed diagnosis of the engine. This will save you from a long search for a breakdown. Almost anything can cause a lack of thrust in a motor.

Often this is faced by owners of new cars. If the diagnostics fail to identify the problem, then you will have to suffer a little. It is connected and will pass to a run of 5000 km. This is most often found in models for which components are assembled in China.

Part wear

Why is the car not accelerating and not pulling? In some cases, this may be due to high levels of engine wear. Usually observed on fairly old machines. Most often, rings suffer, in connection with this, compression drops. Therefore, the first thing to do when reducing power is. If at least in one cylinder the indicator is less than 11, then the engine will have to be overhauled.

Sometimes a decrease in engine power indicates the presence of carbon deposits on the valves, this can only be checked by removing the cylinder head. Indirect signs:

• Change in the ratio of gases in the exhaust;
• Burning on the panel "check".

To eliminate it, you will have to clean the valves. After this work, everything should be back to normal.

Filters

Often the car jerks due to lack of fuel. Fuel filters are installed in every car. Usually there are two. The coarse filter is either in the fuel pump, or it is embedded in the hose. The fine filter is installed in front of the injector. If any of these cleaning devices become clogged, fuel cannot enter the injector in sufficient quantities. Which in turn dramatically reduces the efficiency of the car.

Often in summer clogged air filter. In this case, the mixture is poorly enriched with oxygen, and the fuel does not burn completely. The result is a loss of power. To avoid such problems, it is necessary to replace the filter elements in a timely manner.

Ignition

A modern engine is quite sensitive to the operation of the ignition. Incorrect gap on the electrodes of the spark plugs can lead to failures in the operation of the motor. And, accordingly, to reduce engine power. Therefore, always. You also need to check their performance on a special stand. It can also be done in a simple but reliable way.

To do this, the candle is unscrewed. A high-voltage wire is put on it, after which the engine is scrolled with a starter. The quality of the spark is determined visually. It should be white and blue. If the spark is red or yellow, it is considered to be of poor quality. You should look for a problem in the ignition system. Most likely, this will be the reason for the loss of power.

Diagnostics

For a more accurate definition of the problem, it is desirable. This procedure will help identify problems with sensors and the operation of the power system. To do this, you will need a laptop with a special program. Having deciphered the readings, you need to start troubleshooting. Most often, the reasons may be the following:

• Malfunction of the crankshaft position sensor. With this malfunction, "Check engine" is usually on. The decrease in power occurs due to a mismatch between the pulse supplied to the engine control unit and the actual position of the crankshaft. As a result, incomplete combustion of the fuel occurs, and the efficiency of the motor decreases;
• . This problem can also affect engine power;
• The reason may appear due to. In this case, the "check" will not light up. Therefore, in any case, you need to make a diagnosis.

Conclusion. As you can see, there are enough reasons for the problem and they are all quite diverse. Offhand, not a single auto repairman can say why the car does not accelerate, does not pull. In any case, you will have to carry out thorough and painstaking work on diagnosing and finding the causes of the malfunction.