In modern engines, many mechanisms and systems are involved. All elements are closely interconnected. If one mechanism fails, then the operation of the motor is significantly affected. Hence the feeling that one part can lead to serious problems in the operation of the engine. One of these problems - the car stalls when you press the gas pedal. Let's try to figure out why this is happening.
A problem can happen with any type of engine. The reasons for this trouble are not so many. But not every one of them can be easily identified. Of all the possible reasons, several can be distinguished. Which ones - we will consider further.
Why does this happen?
In fact, there may be several reasons why the engine interrupts after pressing the accelerator pedal. The good news is that in each case there are special symptoms - the breakdown is very easy to identify. If a situation arises when the car stalls after pressing the gas, it is important to understand the essence of what is happening.
The engine stalls only in the morning or in high humidity
If this problem occurs only early in the morning, when the engine is still completely cold or when it is raining, then the moisture that fell on the ignition distributor cover is to blame . This happens due to the fact that during rain, condensation forms inside the lid. The shape of this cover may be such that a misfire occurs due to condensation. As a result, the electric current simply cannot reach the spark plugs. The whole problem is that when the engine is idling, a misfire can be invisible. When the driver presses the accelerator pedal, the distributor works much faster and more current passes through it. In conditions of high humidity, this greatly increases the risk of misfire. The power unit can easily stall under such conditions due to the lack of spark.
Also, the reasons for this operation of the ignition system can be in sufficiently worn sections, poorly insulated high-voltage wires. To check the candles, you need to unscrew them after the car has stalled. Next, examine the state of the electrodes on the candles. The electrodes should be clean with a light red tint. When they are of a different color or have a black coating on them, they are wet and smell like gasoline, it is worth checking the high-voltage wires. If the machine stalls when pressed (gas), the carburetor is checked first. Also, professionals recommend cleaning and revising this part.
How to check?
Diagnosing this trouble is not difficult - just pay attention to whether the problem will recur on a hot motor 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 stalls when you press the gas pedal or not.
The engine stalls more often when you press the accelerator
It also happens that this phenomenon occurs more and more often, and after all, before the engine worked quite stably and only occasionally stalled when pressing the gas. If it 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 very often encounter a vacuum leak.
This malfunction develops smoothly - rarely at first, and then when you press the gas pedal, the car stalls more often. To determine how much fuel the engine should receive at a particular moment, 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 car stalls at the moment of pressing. This problem can be partially diagnosed by a burning light bulb: “Check the engine” on the car dashboard.
It is worth noting that it is not possible to diagnose a vacuum leak on their own in the garage. It is best to use the services of professionals who, on special equipment, will quickly identify a malfunction and fix it. The most common source of this problem is the gas recirculation system and the PCV valve (responsible for crankcase ventilation).
Engine stalls regularly
If the machine stalls when you press the gas each time, then the cause of this malfunction may 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 the amount of fuel is calculated.
If the sensor provides incorrect information, then the control unit may not supply enough fuel to the cylinders, or even do nothing. And this happens exactly at the moment of pressing the accelerator. It is not possible to check this sensor for correct operation in a garage environment - only a replacement.
How to check the fuel system?
The fuel system has many elements and parts that may stop working at any given time. Some nodes can not cope with high loads. At this point, the car stalls when you press the gas. The engine stops working due to the small amount of fuel in the combustion chamber. In this case, it is recommended to check the fuel pump. This is done using a pressure gauge and power to the pump. If the fuel pump is working properly, the pressure gauge will be a figure equal to 2.7 atmospheres. Small deviations are allowed one way or the other. If the number is much less, then the problem is in the faulty pump - it must be replaced. For domestic cars, it is inexpensive - about 1 thousand rubles.
When the car stalls with a sharp pressure on the gas, this is one of the most possible reasons. Malfunctions often occur in nozzles - they spray the combustible mixture into the engine cylinders. They may fail due to fuel quality. In low-quality gasoline there are impurities that pass through the filter. They clog nozzle nozzles. In garage conditions, testing the nozzles will not work - you need a special stand.
You can try to perform an independent 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. In this case, the fuel must be sprayed - if gasoline flows or drips, the nozzles must be changed. A poor atomization level can also lead to problems when the machine stalls when you press the gas.
Fuel filter
Of great importance is the fuel filter.
Quite often, its elements become clogged due to the operation of the car on low-quality fuel. The filter after that is no longer able to pass through the necessary amount of fuel at the moment when the driver presses the accelerator. As a result, the car starts up, pressing the gas stalls. To check what condition the filter is in, you need a pressure gauge - it is connected to the outlet fitting. If the element is clean, then the pressure gauge will show from 2.7 atm. When the pressure gauge is less, then the filter should be replaced.
Drain tube clogging
Very rarely, but nevertheless, there is a clogging of the drainage tube in the filler neck and cover. In this case, a vacuum is created inside the tank, which is the reason for the cessation of fuel supply to the engine.
To check this, at the moment of starting the power unit, the gas tank cover is unscrewed. If after that it was possible to start the machine, then it is necessary to clean the drain pipe and replace the cover.
Intake manifold tightness
An important role in the proper operation of the power unit is tightness. It is reached by gaskets. One of the reasons why the machine stalls when gas is pressed is because of depressurization and air entering the engine through the intake manifold gasket. So, the system does not have the necessary vacuum, which disrupts the process of preparing the fuel mixture. Excess air in the mixture depletes fuel, so the engine stops working. It is almost impossible to detect this defect manually - you only need a specialized stand on which the intake tract will be tested. But air leaks can also occur through the cylinder head gasket due to its burnout. As a result of this, antifreeze enters the cylinders. The engine in this condition cannot work correctly. It is possible to determine that there is coolant in the cylinders by exhaust gases.
If the smoke is white, then the cylinder head gasket must be replaced.
Electronics Issues
In a modern car, all the processes that occur in the engine are controlled by a special computer ECU. This system independently, according to certain programs, selects the optimal modes and the ratio of gasoline and air in the fuel mixture.
In order for the mixture to prepare correctly, the computer collects data from a large number of sensors. So, if the car stalls when you press the gas (injector), then the throttle position sensor, DMRV or coolant temperature could fail. To determine whether the sensors work correctly, you can use special diagnostic devices.
Summary
So, we have listed the main causes of the problem when the engine stops working when you press the accelerator pedal. Both injection and carburetor engines are subject to this. This information will help novice car enthusiasts if the car stalls when you press the gas.