The engine stalls when you press the gas – what could be the reason?
There can be several reasons why a car’s engine stalls when you press the gas after idling. But the good news is that each cause of why the engine stalls when you press on the gas has its own conditions, additional symptoms, so each of these causes is not difficult to identify. Therefore, it is important to understand the situation when this problem occurs. So let’s go in order in order of the most common causes of the engine stalling while trying to start up!
The engine stalls when you press the gas only in the morning or in wet weather. Cause: Moisture on the distributor cap.
If the problem occurs only in the morning, when the engine is still cold, or in rainy or overcast weather, it is caused by moisture on the ignition distributor cap. This is because at night, especially when it rains, there is condensation inside the distributor cap. And the shape of your model car’s distributor cap may be such that it allows the electric current inside the distributor to misfire, causing the electricity to simply not reach the spark plugs.
The problem is that at idle there may not be a misfire, but when you press the gas pedal, the distributor works much faster, running even more current through itself, which in a wet environment only increases the probability of a misfire and, as a result, the engine may stall as soon as you “accelerate” because of the lack of spark.
It is easy enough to check this cause – just pay attention to whether the problem repeats when the engine is warm and the weather is dry. If such weather is not observed, and weather forecasters give rather pessimistic forecasts, then try to put the car in a garage and check whether the engine glows when pressing the gas pedal in such conditions after a long parking.
The engine used to stall when you pressed the gas rarely, but now it’s becoming more frequent. Cause: vacuum leak from the fuel system
When stopping the engine when pressing the gas gradually becomes more and more frequent and does not depend on the weather or time of day, we may be talking about problems with the fuel system. First of all, it’s a vacuum leak. Vacuum leakage problems usually start off infrequently, and then the engine will shut down more and more often due to deteriorating pressure inside the engine. In determining how much fuel the engine should get at any given time, one of the key factors is the vacuum created in the fuel system. But if that vacuum leaks in the fuel system, it will greatly affect the concentration of the air-fuel mixture. This will cause the engine to stall precisely when you “give gas”.
An additional symptom of the malfunction may be the “Check Engine” warning light on.
Unfortunately, this cause is not self-diagnosticating. Take your car to the dealer and have a mechanic check the engine for a vacuum leak. Typically, the most common source of malfunction is the exhaust gas recirculation system, specifically the system’s PCV valve.
The engine stalls regularly when the pedal is depressed. Cause: Throttle position sensor
When the car stalls suddenly and regularly, a possible problem could be a faulty throttle position sensor . The purpose of this device is to measure how far the driver has pressed the accelerator pedal and thus opened the throttle. This data is then fed to the engine ECU, which makes a calculation based on it to determine how much fuel the injection system should inject into the engine combustion chamber. All of this happens, of course, in fractions of a second.
If the throttle position sensor transmits the wrong data, the computer may not inject fuel into the engine combustion chambers at all, and this happens most often when the gas pedal is depressed. Only a mechanic can check the operation of the sensor. An additional signal of this cause may be a burning “Check Engine” indicator.
Other – less common – causes of the engine stalling on the gas pedal may be as follows:
The car stalls when you press the gas
If the car’s engine stops without the driver’s desire, and there is fuel in the tank and no other valid reasons are observed, then some kind of breakdown has occurred. It is clear even to a beginner motorist. But when a car works normally at idle rpm, but stops on gas, it causes bewilderment. Meanwhile, such motor behavior has its own causes and small symptoms that allow these reasons to diagnose, though without inspection at the service station is not always possible to say that the engine stalls, for this specific reason.
DPDZ and other sensors
Most often, if the car stalls when you press the gas, the cause is electronic sensors, because on the basis of information from them, the fuel-air mixture is formed. In particular, it is necessary to check the following sensors:
- idle speed sensor; ;
Again, we are talking about modern cars equipped with direct fuel injection systems, simply speaking, injectors. In most cases, but not always, about a failure of some of the sensors indicates a Check Engine indicator. Determine what sensor is damaged, can only a specialist who has at its disposal the necessary equipment and armed with the necessary knowledge and skills.
That is not always the case, the failed sensor must be immediately replaced. For example, the air flow meter or mass air flow sensor can be washed with aviation kerosene and let it dry. After that, if you are lucky, the sensor will serve more than one tens of thousands of kilometers. By the way, you may also clean the DPDZ. If cleaning does not help, you will have to replace the failed sensor.
Tumbler and moisture problems
If your car glows when you press the gas, but only when the engine is not warmed up and usually in the morning, it is possible that moisture has accumulated under the tumbler cover. Because of this there is a breakdown and as a consequence a disturbance in the distribution of the spark.
This is very easy to determine. Firstly, the car starts to stutter, sneeze, and sometimes it stops even at idle rpm. Well, secondly, in a dark garage or at night, it is enough to open the hood and start the engine. All breakdowns will show their face at once. In general, the problem is very eloquent and easy to diagnose. Well, it can be eliminated either by replacing the ignition distributor cap, or by eliminating moisture ingress in any other way.
If the cases when the car stops on the accelerator pedal are becoming more and more frequent and are not related to moisture and problems in the electronic components of the car, then most likely the fuel system is sick. And the first thing to check is how the vacuum is doing. By default, the car’s fuel system has a vacuum. But if its tightness is broken, various problems related to insufficient fuel supply to the engine are possible. Stopping the engine when the accelerator pedal is depressed is an eloquent symptom of such problems. But only an experienced mechanic is able to determine such a problem. At vacuum disturbances in the fuel system, Check Engine indicator may also light up.
Read also : Why the car stalls on braking .
Other possible problems
Also, the car may stall when the accelerator pedal is depressed and for other reasons. Although they are not as common as those described above, such causes are nevertheless common, and you should be aware of them.
- Poor-quality or worn spark plugs;
- problems with the catalytic converter;
- clogged air or fuel filter;
Actually, even this list of factors that cause the engine to stop when pressing the gas, can not be considered exhaustive. Much will depend on the car model, on the peculiarities of its engine and fuel system design. In general, if you exclude all the problems with spark plugs and ignition, it is safe to say that the car stalls when you press the gas, either because of problems with the fuel supply, or because of problems with the air supply. These are the two main components of the fuel-air mixture on which all car engines run, apart from electric cars, of course.
As we can see, in most cases, the problems that cause the engine to stop after the gas pedal is pressed can only be corrected by a specialist. Nevertheless, nothing critical, apart from the fact that the car simply cannot be used normally, such symptoms do not mean, and as a rule, even expensive repairs are not required, except in those cases when it is necessary to replace the catalyst. Since this unit is very expensive, regardless of the car model. But replacement of sensors or filters, will not affect your pocket greatly.
Therefore, as soon as the similar situation has arisen and is repeated at least twice, it is necessary to apply to service stations, as the fact that the car stalls right in the course of a trip is at least uncomfortable and unpleasant.