The engine stalls on a hot: reasons
Failure of a power unit to run cold or after warming up to a certain temperature may indicate a fairly wide list of possible problems. The engine starts to stall both suddenly and unstable in different modes, after which the internal combustion engine stops.
In this article, we will talk about the reasons why the engine stops at idle speed, as a result of which a warm engine stalls, why a car stalls on a hot engine in motion, etc.
A hot engine stalls on the move or at idle
To begin with, the symptoms and signs of this problem can manifest themselves in different ways. Quite often, the power unit can stall in idle mode, and the unstable operation and complete stop of the internal combustion engine often occurs after the engine has warmed up.
First of all, diagnostics should start with checking the spark plugs and their condition. In parallel, high-voltage armored wires should be checked. This must be done due to the fact that weak sparking or complete absence of a spark on the spark plug electrodes is possible. Interruptions in the spark lead to serious malfunctions of the engine, as a result of which both the cold unit and after warming up the engine stalls. Replacing spark plugs and high-voltage wires often helps to solve the problem.
Another common situation is when the engine stalls hot or cold immediately after starting. In this case, on many modern cars with an injection power system, the idle sensor should be checked. The output of this element of the electronic engine control system often leads to the fact that the engine in idle speed is simply unable to work.
In some cases, cleaning the XX regulator helps, in others the device should be replaced. On cars with a carburetor, the idle jets may become clogged and other carburetor malfunctions. Injection motors also require an additional check of the synchronization sensor (DPKV); possible problems with the gas pump should not be ruled out. One way or another, if the engine stalls on a hot one or it constantly happens with a cold unit, then in-depth diagnostics will be required.
On carburetor cars with a mechanical ignition distributor, a situation arises when the slider stops performing its functions. Quite often, after the internal combustion engine warms up, the central wire on the ignition coil may go off, there are problems with the capacitor of the ignition unit, etc. A well-known problem of cars with a mechanical gas pump is that the engine stalls in the heat. This is due to overheating, since the high temperature overboard and significant heating of the engine compartment do not allow the pump to cool normally.
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In parallel, attention should be paid to the condition of the fuel filters. If the filter element is clogged, then during an increase in the load and a rise in speed, the required amount of fuel does not enter the engine through the dirty filter and the engine stalls. We add that usually, before a significant decrease in the filter capacity and a complete stop of the motor, the malfunction progresses. At first, the car may not pick up speed, it starts poorly, dips appear when you press the gas pedal, the engine is unstable or jerks when you press the accelerator, in transient modes, etc.
Modern cars with an injector have an electronic control unit (ECU, ECU). This unit is quite rare, but still fails. In this case, the engine may stall on the move, and the problem itself manifests itself in different situations, including after the internal combustion engine has warmed up. In this case, as well as if it is necessary to check individual ECM sensors, it is necessary to carry out computer diagnostics of the car. The system will display the existing errors in the form of codes, after decoding of which it is possible to localize the malfunction. If the problem is “floating”, that is, it occurs periodically, then it is recommended to purchase a compact device that allows you to read information about the engine operation via the OBD connector. Due to the subsequent display of data on the screen of a smartphone, tablet or laptop with a preinstalled program, this solution will allow fixing failures in real time.
Other reasons why the engine stalls when hot
In addition to the above material, I would like to note a number of malfunctions that lead to a sudden stop of a hot engine while driving. The unit can stall on the move if the timing belt or chain breaks. This situation means that in most cases, the power unit will need expensive repairs, since as a result of a breakage, the valves are bent, piston defects and other damage to engine elements occur.
If the engine stalls while driving through deep puddles or other water obstacles, then there is a high probability of water entering the cylinders or wetting the ignition system elements. In the first case, water enters the combustion chambers through the air intake. Since the water is incompressible, the engine is severely damaged, the connecting rods bend, cracks appear in the cylinder block, etc. After a water hammer, it is usually necessary to overhaul the engine. In the second case, the problem is not critical, since after removing moisture, the performance of the ignition system and the power unit can often be restored.
Also, a car can stall on a hot one if there is too little fuel in the fuel tank. Quite often, the motor stops when driving uphill. The fact is that during a prolonged ascent, the car is in such a position for a long time when the fuel tank is tilted and the fuel level is insufficient to supply through the fuel intake. It is quite obvious that in this case the engine will stall.
What is the bottom line
As you can see, there are many reasons why a motor stalls when hot. In some cases, the engine normally starts cold and warms up, but after pressing the gas pedal, the speed drops and the car stalls.
Stopping the engine is often preceded by interruptions in normal operation. In the event of a refusal of the gasoline pump or the production of residual fuel in the fuel tank, before stalling, the engine begins to twitch, since the gas pump picks up air along with the residual fuel. A clogged fuel filter can manifest itself in a peculiar way. At idle or while driving at low speed, the engine works normally, but during acceleration or heavy load, the filter capacity is no longer enough, and a lean mixture enters the cylinders, as a result of which the car stalls on the go. To check the flow of fuel in injection engines, it is necessary to measure the pressure in the fuel rail. It must not be less than the set value for this type of motor.
In the same way, clogging of the air filter affects the operation.
An improperly adjusted carburetor produces an over-enriched mixture, as a result of which it can flood the candles, which will cause them to fail.
As a result of incorrect valve adjustment, filling with low-quality gasoline or with an unacceptable octane number, valve burnout may occur. Valves in one of the cylinders usually burn out. The engine begins to triple, loses power abruptly and may stall. Burnout of valves in two or more cylinders causes an instant engine stop. Such a malfunction is checked using a compression meter in each cylinder. The reduced compression value will tell in which of the cylinders the breakdown occurred.
A modern car is equipped with an exhaust gas catalytic converter. If the catalytic converter is destroyed, the exhaust gases cannot leave the combustion chamber, which will also lead to a stop. The catalyst can only be checked by removing it from the exhaust system.
Injection engine problems
Why does the car stall on the move
There can be many reasons that a car stalls on the move while driving. This can be a malfunction of the fuel system, or problems with the engine or ignition system. Many reasons for stopping the engine are possible only on the carburetor system, and some. only on the injection system. The nature of the engine operation at the moment before stopping can indicate the direction of troubleshooting. Often after stopping it is possible to restart the engine and continue driving. This behavior should also participate in the logic of finding the problem, why the car stalled. It should be noted that the injection vehicle has more reasons for sudden breakdowns.
Sudden engine stop
If the engine was running normally while the car was moving, and the car suddenly stalled, then the following may have happened:
- clogging of the carburetor jets;
- breakdown of the gas pump;
- breakage of the timing belt;
- malfunction of the crankshaft position sensor;
- malfunction of the idle speed controller;
- malfunction of the ignition distribution system.
Checking the fuel pump relay
often, a breakdown of the fuel pump relay occurs. To check it, you need to turn the ignition switch on the muffled engine. A click should be heard in the area of the relay, and within a few seconds the gas pump will start working. If there is a click, and the pump does not work, the contacts in the relay may have burned out. This can be checked with an ohmmeter on a de-energized relay and after applying a 12 V voltage to its winding from the battery terminals. Open contacts should show infinity, and closed contacts should show resistance in fractions of ohms. If the relay is working properly, you need to check the ground connection to the fuel pump.
Trimmer power loss at full throttle
Idle speed regulator malfunction
Malfunction of the idle speed control when the car is moving stops the engine when you release the gas pedal and close the throttle.
You can check the regulator by removing it from the fuel system. A good regulator should show a resistance between the terminals of the order of 20–80 ohms. When connecting the terminal with the ignition on, the regulator rod should make some movement.
For the first time, in order to bring the car to the service station without assistance, you need to remove the terminals from the regulator and manually, with the help of several attempts, find such a position of the rod when the engine is idling steadily so that the car does not stall when the gas is released.
Looking for reasons
All of the above reasons, with the exception of a breakdown of the crankshaft sensor, can be determined independently in a minimum of time. First of all, you need to understand whether the combustible mixture enters the combustion chambers of the engine. To do this, you need to unscrew and examine the spark plugs. If the spark plugs are dry, the cause is most likely in the fuel system. In a carburetor machine, more often the reason lies in the carburetor. There are many reasons, ranging from clogged fuel jets to lack of fuel in the float chamber. The fuel level in the float chamber is regulated by a needle valve connected to the float. The float may catch on the chamber body and not open the valve.
Clogging of the needle valve or jets can be caused by the ingress of foreign unfiltered particles or tar deposits as a result of the use of low-quality fuel. Resins are cleaned with aerosol cans with carburetor cleaner, and blockages are cleaned by blowing air from the compressor.
It is strictly forbidden to clean the nozzle holes with a metal wire. Burrs left by the wire will change the characteristics of the jets and require replacement and subsequent adjustment of the carburetor.
Wet spark plugs indicate that the engine has a working fuel system.
Immediately check the ignition system for a spark. If all the candles have traces of fuel and a spark, then conclusions can be drawn about the health of the ignition and fuel supply systems. It is worth warning that a malfunction of a single spark plug or spark plug wire cannot stop the engine. This happens if only the ignition distributor fails. distributor, module or ignition coil.
The camshaft drive belt can be viewed by removing its cover. On many vehicles, a break in the timing belt is accompanied by a violent shock when stopped. This occurs as a result of the uncoordinated movement of the valves and the piston and their mutual blows. The pistons have no grooves, which is why they collide with the valves. On such engines, checking the condition of the belt should be given special attention at regular intervals. Some engines have grooves on the pistons, so a break in the timing belt goes completely without a trace for them.
The collector shaft position sensor can only be checked by installing a new one on the vehicle. None of the engine sensors will cause the engine to stop again, since the on-board controller has several backup algorithms and will ensure the engine’s performance, albeit with increased fuel consumption and with a decrease in power. At first, with such breakdowns, you can continue to move.
The operation of the electric fuel pump of injection vehicles is checked by the presence of fuel in the fuel rail.
Electrical and battery malfunctions
Do not ignore the possible causes of electrical malfunction. Oxidized ground wires on the body and engine housing can also cause engine problems. But why, knowing about the prevalence of such a problem, many do not pay special attention to it.
But such a reason as the failure of the on-board controller is extremely rare. This can occur in the event of poor contact at the battery terminals. Then the relay-regulator of a running generator cannot quickly track voltage fluctuations, and it can jump to a high value. Why it is not recommended to remove the terminals from the battery during operation.
The benzokosa stalls or suffocates when you press the gas
At idle, common reasons for stopping the trimmer are as follows:
- contamination, misalignment or incorrectly adjusted carburetor adjustment;
- clogged air filter;
Replacing the air filter of brushcutters
Trimmer air filter
Fixing an Echo trimmer that starts but dies.
- reducing the speed of the gearbox when it heats up, which is a consequence of the use of an unsuitable fuel mixture;
- clogged throttle;
- air ingress into the system;
- not enough fuel to operate the petrol cutter.
If the problem area is the carburetor, then the equipment will stop at both “cold” and “hot” start.
The chainsaw stalls at high speeds. simple carburetor repair
The carburetor of the instrument is exactly the mechanism that most owners are afraid to disassemble on their own. The reason is that this mechanism consists of many small parts, the location of which must be remembered when carrying out dismantling work. However, not everything is as scary and difficult as it might seem. To understand how the carburetor has to do with the problem of stopping the engine when the engine speed increases, you need to find out its principle of operation, described on the website.
The chainsaw stalls when you press the gas due to the carburetor, if:
- Diaphragm damaged
- Clogged filter element (mesh in the carburetor). This malfunction can be encountered by owners of tools who do not have a fuel filter or it is simply disconnected from the fuel hose.
- Needle sticking, which may be due to the use of an outdated fuel mixture
- Clogged nozzles or clogged carburetor
- Bending of the connecting part connecting the membrane with the needle to supply fuel to the fuel chamber of the carburetor. This part is also called a foot, since under the influence of the membrane on it, the needle moves and the channel opens. During operation, this foot can bend (work out) or break (the engine will not start if it breaks). If the foot is bent, then it can be unbent, but this does not guarantee that the problem will soon recur, therefore it is recommended to replace the part
It is recommended to clean and wash the chainsaw carburetor, as well as replace defective parts and elements. After that, you can put it back, not forgetting to also replace (if worn out) the gasket between the carburetor and the adapter.
The scythe stalls when the gas is pressed. Construction portal
A scythe with a gasoline drive is a useful thing for owners of home gardens, lawns, and when the trimmer suddenly stalls, the work to clear the area from grass stops. The device itself is a rather complex mechanism, so there are many different reasons for its breakdown. The most common malfunctions are contained in the operating instructions. You should know the reasons why the trimmer stalls in order to effectively repair the device yourself.
Stalls at high speeds
When the chainsaw starts to stall at high speeds, the following parts must be checked:
- air filter;
- fuel pump;
- fuel filter.
The air filter must be cleaned, for which it is enough to wash and dry it (paper filter. only change). You can check for a clogged fuel filter by disconnecting the fuel hose from the carburetor. If the trickle of gas from the hose is flowing well, then you do not need to check or replace the fuel filter. If the trickle is weak or there are no signs of fuel supply at all, then the filter should be replaced and the breather should be cleaned with a regular needle.
Checking the fuel pump is checked for characteristic signs of fuel seeping through it. If there are no signs of leakage, then everything is in order, then it remains to check the carburetor. Depending on the saw power, the maximum speed is set, which can be checked using an electronic tachometer.
As can be seen from the description, there are many reasons why the chainsaw starts and stalls. Most often, this occurs due to an incorrect carburetor setting, although on branded chainsaws, such as Stihl, Husquarna, adjusting the carburetor is a rare event if you fill in a high-quality fuel mixture. If malfunctions and malfunctions occur in the operation of the tool, it is recommended to diagnose and repair it, and continue using it only after eliminating the malfunction. It is not uncommon for minor signs of failure to become serious problems for tool owners.
Stalls at idle speed
If the chainsaw does not start well and stalls at idle, then the first reason is a clogged muffler. The muffler should be dismantled and then wet cleaned. This is very important, as dust can enter the lungs during dry cleaning, which will lead to serious disruption of the functioning of the respiratory system.
The second reason that the chainsaw stalls at idle is an incorrect carburetor setting. To idle the chainsaw, tighten the screw called L on the carburetor. If the tool stalls at idle speed, the screw should be turned 0.5 turns clockwise. To accurately adjust the carburetor, it is recommended to use a tachometer, and the tuning technology is described in this article (link).
When the air damper is opened
It happens that the unit stalls when the air damper is opened, normally idling. This is due to air leaks in the system, caused by cracks in the fuel hose or problems with the oil seals. The carburetor dosing system may also malfunction, while the brushcutter will stop after opening the damper.
Fuel hose in carburetor
All possible reasons that the petrol brush stalls, and how to eliminate them, are contained in the following video
There are many reasons for stopping the brushcutter, but the most common malfunctions associated with its carburetor. They can arise in any case. The most problematic option is when a serious breakdown occurs, and you need to purchase new parts or change the petrol cutter.
In order for the trimmer to work normally for a long time, you must strictly follow the instructions for use. It is necessary to fill the unit with a suitable fuel mixture, the unit should operate at moderate load.