Why Cars Stall While Driving (And Points for Attention)

A defective vehicle engine causes stalling. Then the startup is not very smooth. Car stalling can be very dangerous, especially when it runs at high speed. It is the hidden trouble to intrigue serious traffic accidents. Besides, stalling brings great inconvenience to everyone's normal life. So what is the problem with the frequent stalling of the car?

1. Reason for stalling

    1.1 Fuel system

    1.2 Ignition system

    1.3 Air supply system

2. Points for attention

1. Reason for stalling

1.1  Fuel system

●  Blocked fuel line

When the car is running on the road, the fuel pump in the engine is the first component to pump fuel from the tank. The fuel goes through the fuel filter and comes into the fuel distribution line. The fuel nozzle then injects it to form the air-fuel mixture.

The fuel flows through the electric fuel pump, the fuel filter, and the fuel line when the engine is working. The injector finally sprays the fuel. In this process, the injector and fuel pump are the places where failures are most likely to occur.

The electric fuel pump has its duty to pump the fuel from the tank into the fuel line to send fuel needed for each injection system. Usually, it is immersed in petrol and cooled down.

Delcoribo Fuel System Parts

Impurities may cause blockage in the gasoline. It is a typical issue. In order to reduce this fault, we have to make fuel charging in the formal service station in the daily life. Meanwhile, we should pump the fuel in time. Too little fuel (below the red line) damages the engine.

●  Defective fuel injectors

The fuel injectors used in EFI engines are electromagnetic types. The pressurized petrol is sprayed out from the injector under the electromagnetic coil's magnetic field.

The common failures are leakage, blockage and sticking of the injector nozzle, and short circuit, broken circuit and failure caused by degeneration of the solenoid coil. In addition to adding the standard fuel, we should also take care of whether the gasoline filter can still work properly.

In addition, another problem that can lead to car stall in the system is a dirty fuel filter.

1.2 Ignition system

●  Spark plug (abnormal ignition)

When the air-fuel mixture comes into the cylinder typically, but the engine still stalls, it is most likely that the ignition system is faulty.

The ignition system produces enough strong sparks in the spark plug regularly between two electrodes by the working order of the cylinder. One of the most core parts is the spark plug. 

Due to working in the high pressure and high temperature cylinder, the spark plug is also the most vulnerable component in the ignition system.

Normally, the service life of the spark plug is 20-30 km. The service life of the platinum spark plug can reach 100 km.

Common issues of spark plugs include leakage, abnormal puncture voltage and burned-out electrode. Usually, in the symptom of installing caused by spark plugs, replacing the spark plugs completely is the best way to resolve the issue.

If it is unhandy to do this job, you can clean the electrode and adjust the length of the central electrode to carry out temporary solutions.

Delcoribo Ignition System Parts

●  Failure in alternator

The faulty wiring and loose belt in the alternator will not provide enough power to the spark plug, which leads to stalling.

Besides faulty spark plugs, the damaged alternator, short circuit in the wiring, false connection and the leaking battery can also lead to abnormal ignition due to the lack of power.

These symptoms will eventually cause the engine to stall. When these things happen, you can check if the belt is broken or too loose. To determine if there is power, press the horn. In other situations, problems with ignition coils can also pull the trigger for stalling.

1.3 Air supply system

●  Blocked throttle valve

The air supply device and oil supply device are equally important. The smooth flow of the former one is also the key to ensure the typical ratio of the fuel to the gas mixture.

In this system, the air comes through the air filter, air flow meter, throttle body intake main pipe, intake manifold, and finally, the air goes into the cylinder.

In the air supply system, the throttle is undoubtedly the most critical component. It is also the most vulnerable one. In most repair stores, the first thing to check after the stalling problem is the throttle in the intake throttle position.

The throttle is the throat of the engine. The blockage caused by insufficient air intake often leads to the engine stalling.

The function of the throttle is to control the amount of combustible mixture entering the cylinder by adjusting the size of the throttling threshold. The space is small since the throttle is opened in the gap where the air flow is the largest. And the gas temperature is low.

This place is most likely to condense impurities. So it needs to be cleaned according to a particular period cycle. If impurities block the throttle, it will lead to the insufficient air intake, which causes stalling and unstable idle speed.

●  Intake manifold leaks

The presence of leaks in the intake manifold can lead to unstable idling or even stalling. The vehicle will have a strong judder when such a problem occurs.

Before the air-fuel mixture enters the cylinder, it has to pass through the intake manifold. In order to suck in the air, the intake stroke of a natural intake engine mainly relies on the vacuum in the cylinder.

When there is a leak in the intake pipe, the vacuum is too small to suck in enough air, which will cause the engine to run weakly. It isn't easy to start. There are symptoms like unstable idle speed, substandard emissions and even stalling.

The performance of intense shaking happens during driving when there is a vacuum leak. So this kind of fault is easy to judge.

2. Points for attention

When the engine stalling happens on the road, there are several points for attention.

●  Turn off the air conditioner

Many car owners like to turn on the air conditioner after the engine stalling. They do not know that this is very harmful to the battery.

When the vehicle starts again, it will start with the air conditioner on. In this way, the vehicle's instant load will be very high. The battery will be damaged in long-term working.

Continue to use electricity after shutting the engine down has a terrible impact on the battery. The power of devices on the car is relatively large. The battery power can be rapidly reduced.

For more helpful advice, information on the automotive engine, take a look at our other recent blog posts.

●  Don't listen to music

Listening to music for a long time after stalling will also bring damage to the battery and increase the load. When the engine is turned off, the source of power for the car stereo is the battery. The engine is turned off to stop generating electricity.

It should be noted that listening to music for 4 hours after turning off the engine will consume electricity to nothing. Then you can't start the engine.

So if you want to let the car run smoothly, don't listen to music for more than one hour after turning off the engine. This behavior will decrease the battery performance.

●  Unplug the external device from the power port

For convenience sake, many car owners often connect the power to many devices, such as GPS, car recorder, air purifier, etc.

Power interfaces of some models are still in the power mode under the stalling state. If you don't unplug external devices, they will consume battery power and wear out the battery.

●  Turn off vehicle lights

When the car suddenly stops working, you may forget to turn off the vehicle lights. This is the time to pay special attention, especially to the clearance lamp. The clearance lamp stays on until the battery is emptied.

Lauritz Carolsfeld        October 19, 2021
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