Why does the car stall when you press the gas?

In modern engines, many mechanisms and systems are involved. All the elements are closely related. If one of the mechanisms fails, then the motor is significantly affected. Hence the feeling that one detail can lead to serious problems in the engine. One of these problems is the vehicle stalling when the gas pedal is depressed. Let's try to figure out why this happens. The problem can happen with any type of engine. The reasons for this trouble is not so much. But not every one of them can be easily identified. Of all the possible causes can be identified several. Which ones - we will consider further.

Why does this happen?

In fact, the reasons why the engine interrupts the operation after pressing the accelerator pedal may be several. The good news is that in each case there are special symptoms - the breakdown is very easy to determine. If there is a situation when the machine stalls after pressing the gas, it is important to understand the essence of what is happening.

The engine stalls only in the mornings or in conditions of high humidity

If this problem happens only in the early morning, when the motor is still completely cold or when it rains, then the moisture that hit the ignition distributor cover is the fault . It happens because of the fact that during the rain inside the lid condensation forms. The shape of this cover itself can be such that a misfire occurs due to condensation. As a result, the electric current simply can not reach the spark plugs. The whole problem is that when the engine is running at idle, the misfire may not be noticeable. When the driver presses the accelerator pedal, the distributor runs much faster and more current flows through it. In conditions of high humidity, this greatly increases the risk of misfiring. The power unit can easily die out in such conditions because of the absence of a spark. Also, the reasons for this operation of the ignition system can be in sufficiently worn out sections, poorly insulated high-voltage wires. To check the candles, you need to unscrew them after the car has decayed. Next, they study the state of the candle electrodes. Electrodes should be clean with a light red tinge. When they are of a different color or have a black coating on them, wet and smell of gasoline, it is worth checking the high-voltage wires. If the machine stalls while pressing (gas), the carburetor is checked first. Also, professionals recommend cleaning and auditing this part.

How to check?

Diagnosing this trouble is not difficult - just pay attention to whether the problem will repeat on a hot engine on a dry day. If this weather is not promised and weather forecasters make a pessimistic forecast, then you can put the car in the garage and after some time check whether the car is deaf if you press the gas pedal or not.

The engine stalls when you press the accelerator

It also happens that this phenomenon occurs more and more often, and in fact the motor used to work quite stably and was deaf when pressed on gas only occasionally. If this does not depend on the weather outside the window and the time of day, then in this case we are talking about possible problems in the fuel system. Specialists are very often faced with a vacuum leak. This fault develops smoothly - at first it is rare, and then when the gas pedal is depressed the machine stalls more and more often. To determine how much fuel a motor should receive at a particular time, one of the main factors is precisely the vacuum that is created in the fuel lines. And if there is a leak in the fuel supply system , this will greatly affect the composition of the air-fuel mixture. This leads to the fact that the machine stalls at the moment of pressing. This problem can be partially diagnosed by the burning light bulb: "Check the engine" on the dashboard of the car.

It is worth noting that it is not possible to diagnose a vacuum leak by yourself in the garage. It is best to use the services of professionals who on a special equipment will quickly identify a malfunction and eliminate it. The most common source of this problem is the gas recirculation system and the PCV valve (responsible for the crankcase ventilation).

The engine stalls regularly

If the machine stalls when you press the throttle every time, then the cause of this problem can be the throttle position sensor . The main task of this element is to measure how the driver presses the gas pedal and at what angle to open the throttle at a particular moment. Further, the sensor sends data to the engine ECU, where fuel quantity calculations are performed. If the sensor generates incorrect information, then the control unit can supply an insufficient amount of fuel to the cylinders, or even do nothing at all. And it happens when the accelerator is pressed. It is not possible to check this sensor for proper operation in the garage conditions - only replacement.

How to check the fuel system?

As part of the fuel system, many elements and parts that can stop working at any time. Some nodes do not cope with high loads. At this point, the machine stalls when you press the gas. The engine stops working because of the small amount of fuel in the combustion chamber. In this case, it is recommended to check the petrol pump. This is done by using a pressure gauge and supplying power to the pump. If the gasoline pump works properly, the gauge will have a digit equal to 2.7 atmospheres. Small deviations in one or the other side are permissible. If the number is much smaller, then the problem in the faulty pump - it must be replaced. For domestic cars it is inexpensive - about 1 thousand rubles.

When the machine is stunned when you suddenly press the gas, this is one of the most possible causes. Often there are malfunctions in the nozzles - they spray the combustible mixture into the cylinders of the engine. They can fail because of the quality of the fuel. In poor-quality gasoline there are impurities that pass through the filter. They also clog nozzles of injectors. In the garage conditions, it will not be possible to test the nozzles - you need a special stand.

You can try and carry out self-diagnosis, but for this, the nozzle really needs to be broken. For the test, unscrew the fuel rail. The nozzles are diverted to the other side of the motor, and then the starter is started. At the same time, the fuel must be sprayed - if the gasoline flows or drips, the injectors must be changed. A poor level of spraying can also lead to problems when the machine stalls when you press the gas.

Fuel filter

The fuel filter is also very important. Quite often, its elements become clogged because of the car's operation on poor-quality fuel. The filter after this is no longer able to pass through the necessary amount of fuel at the time when the driver presses the accelerator. As a result, the machine starts, pressing the gas - stalls. To check the condition of the filter, you need a pressure gauge - it is connected to the outlet fitting. If the element is clean, then the manometer will show from 2.7 atm. When the manometer reading is less, then the filter should be replaced.

Clogged drainage pipe

Very rarely, but still there is a clogging of the drainage pipe in the filler neck and lid. In this case, a vacuum is created inside the tank, which is the reason for stopping the fuel supply to the engine.

To check this, at the time of starting the power unit, unscrew the lid of the fuel tank. If after this it was possible to start the car, then it is necessary to clean the drain pipe and replace the cover.

Intake manifold leaktightness

The tightness plays an important role in the correct operation of the power unit. It is achieved with the help of gaskets. One of the reasons why the machine stalls when gas is pressed is depressurization and air entering the engine through the intake manifold gasket. Thus, there is no necessary rarefaction in the system, which disrupts the process of preparing the fuel mixture. Excess air in the mixture depletes fuel, so the engine also stops working. It is practically impossible to detect this defect by hand - only a specialized stand is needed, on which the intake path will be tested. But sucking air can also occur through the cylinder head gasket due to its burnout. As a result, antifreeze enters the cylinders. The engine in this condition can not work properly. Determine that there is a cooling liquid in the cylinders, it is possible by exhaust gases. If the smoke is white, then you need to replace the cylinder head gasket.

Problems in electronics

In a modern car, all the processes that occur in the engine are controlled by a special computer of the computer. This system independently for certain programs chooses the optimal modes and the ratio of gasoline and air in the fuel mixture. For the mixture to be prepared correctly, the computer collects data from a large number of sensors. So, if the machine stalls when you press the gas (injector), then the throttle position sensor, DMRV or coolant temperature could be damaged. Determine whether the sensors work correctly, using special diagnostic devices.


So, we listed the main causes of the problem when the engine stops working when you press the accelerator pedal. This is subject to both injector and carburetor engines. This information will help novice car enthusiasts if the car stalls when you press the gas.

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