Why Does a Car Engine Stop While Driving?

Sep 20, 2023 / 17 Minutes Read / By Albert / 0 Comments

Table of Contents:

There are multiple causes for a car to unexpectedly turn off while driving. Some common reasons include a malfunctioning crankshaft position sensor, a faulty fuel pump or fuel supply system, an empty fuel tank, alternator issues, and a defective ignition switch.

Fuel delivery system issues can result in several symptoms in your car. One of the common signs is difficulty starting or the car not starting at all. Additionally, engine misfiring can occur when one or more cylinders fail to ignite correctly. Another indicator is engine idling issues, where the engine runs unevenly at low RPMs. In addition, you may experience reduced power and acceleration. Finally, fuel efficiency may decrease, leading to increased gas consumption.

Can low fuel pressure cause a car to not start?

Insufficient fuel pressure can hinder the ignition process of a car's engine. During startup, the vehicle requires an ample amount of fuel, and if it doesn't receive the appropriate fuel supply, it may fail to start. One may notice delayed ignition or multiple attempts needed to successfully start the car.

What is fuel delivery testing?

Fuel delivery testing is crucial to ensure that the adequate fuel pressure and volume are consistently provided in various operating conditions. This testing process can be divided into two main categories, with all fuel delivery procedures following a similar approach. These procedures are designed to measure both the pressure and volume of fuel that is being supplied through the system, adhering to standardized testing conditions.

What happens if you put too much fuel pressure?

Insufficient pressure can result in the engine being deprived of fuel, leading to issues such as lean running, misfiring, hesitation, or stalling. On the other hand, excessive fuel pressure can cause rough running, fuel wastage, and increased pollution. It is crucial to have a clear understanding of the specific fuel system before initiating any diagnostic tests.

Are there any signs of a faulty ignition system causing the engine to shut off?

The symptoms of a faulty ignition switch include a car that unexpectedly shuts off while driving. This can be one of the initial signs of a problem.

An additional symptom is when the engine fails to start when the key is turned. The car may also start briefly and then stall suddenly.

Other issues with the ignition switch can involve difficulties in powering on the accessories or problems with turning or removing the key.

Can a bad ignition switch stop a car from starting?

A faulty ignition switch is unable to provide power to essential components such as the starter motor, ignition system, and other engine controls, resulting in the engine being unable to start.

It is important to note that engine problems can also be caused by other issues, both electrical and mechanical, such as a dead battery or a malfunctioning starter solenoid.

How do I know if my ignition switch is bad?

The inability of an engine to start can indicate a faulty ignition switch. The ignition switch is responsible for supplying power to various components such as the starter motor, engine controls, and ignition controls. When the ignition switch malfunctions, these systems may not receive the necessary power to start the engine, resulting in the engine not starting.

Why is my ignition key stuck when removing the key?

When the ignition key becomes stuck while turning on the car or removing it, it could indicate a potential issue with a worn out ignition switch.

The key may not properly connect within the switch, leading to this problem. In addition, a faulty switch may cause the engine to keep running even after the key has been removed.

These are common symptoms of a bad or failing ignition switch.

Source: Symptoms of a Bad or Failing Ignition Switch - YourMechanic

What happens when the ignition is on?

When the ignition is in the ON position, various systems such as HVAC controls and dash instruments are activated. This position is necessary for the operation of systems that require the engine to be running. Additionally, it is important to have the ignition in this position when the car is running.

Is the car displaying any warning lights or error codes indicating a problem with the engine?

Car warning lights and codes are utilized to indicate potential issues with your vehicle. Several of the most frequently encountered car warning lights and their meanings include the Check Engine/Service Engine Light, Oil Pressure Warning Light, Temperature Warning Light, Tire Pressure Sensor Light, and Battery Alert. Automotive professionals rely on OBD2 codes (On-Board Diagnostics II) or Fault Codes to identify and diagnose the problem.

Check also Why Is Driving a Car a Responsibility?

What does a check engine light mean on a car?

The check-engine light is widely disliked by car owners due to its significance. Typically, this warning is represented by an engine silhouette, although in some cases, it may be displayed as a prominent "CHECK ENGINE" message in capital letters.

The presence of dashboard warning lights, including the check-engine light, has been thoroughly explained by Car and Driver in an article titled "Dashboard Warning Lights Explained."

What does a warning light mean on a car?

A warning light on the dashboard, instrument cluster, infotainment display, or smartphone app indicates a possible issue with the vehicle. The interpretation of these warning lights can vary in terms of intuitiveness, although their design and methodology have remained relatively consistent over time.

Understanding the meaning behind the dashboard lights in your car is crucial for prompt and appropriate action. Familiarizing yourself with the various warning lights can help you identify and address any potential problems with your vehicle.

What happens if you ignore check engine light warning?

Ignoring the warning from the check engine light can lead to a snowball effect, where a small and inexpensive part malfunctioning can gradually cause more damage to other car parts. As a result, the replacement of these damaged parts can become more expensive.

It is important to address the issue indicated by the check engine light promptly to prevent further damage and costly repairs.

Why does my car have a code 'lean condition'?

The ECM will activate this code when it detects that the engine is operating below the designated temperature, based on readings from dedicated sensors such as intake air and ETC.

In addition to replacing the thermostat, it is possible that trapped air bubbles in the cooling system may be the culprit for this issue.

This particular code is triggered when the engine burns more air than fuel, which is referred to as a lean condition.

To determine whether the issue lies with the alternator or the battery, there are steps you can take. If your vehicle starts with the battery but then dies while running, it suggests a faulty alternator. On the other hand, if your battery has been charged but still cannot start the vehicle, it indicates a battery problem.

To further troubleshoot, you can bypass the battery by jump starting your car. If the engine starts briefly but then dies, it points to a potential issue with the alternator. Conversely, if the engine continues to run after a jump start but fails to start again using its own power, it signifies a battery-related problem.

A defective alternator can have a direct impact on the battery, leading to damage not only to the electrical components but also to the overall functioning of the car.

Check also Why Did My Car Break Down While Driving?

Does having a bad alternator ruin a car battery?

Interestingly, a faulty alternator can also fail to properly charge the battery, leading to inadequate power to keep the battery functioning optimally.

Continued instances of this can cause damage to the battery over time.

Therefore, it is evident that neglecting a faulty alternator can potentially result in harm to the battery.

How do I know if its the battery or the alternator?

If your vehicle initially runs smoothly but starts to malfunction after a few minutes, the likely culprit is a faulty alternator.

If your car battery is unable to maintain its charge, it indicates an issue either with the alternator or the battery itself.

On the other hand, if your battery is able to start the car but fails to stay powered as the vehicle runs, the problem lies with the alternator.

Can you start a car with a bad alternator?

It is possible to start a car with a faulty alternator, and the vehicle will remain operational for a period of time, despite the alternator being defective. This is because when the alternator is malfunctioning and not generating voltage, the car will solely rely on its battery for power.

However, it is important to note that continually running a car with a faulty alternator can have negative consequences. Operating solely on the battery can cause it to become drained, resulting in the car eventually stalling and becoming inoperable.

Therefore, while jumpstarting a car with a bad alternator is a temporary solution, it is crucial to address the issue and repair or replace the alternator to ensure the proper functioning of the vehicle.

Is the car experiencing a loss of power or hesitation before the engine shuts down?

Hesitation and loss of power can indicate that the engine is not receiving the correct combination of air and fuel, both of which are necessary for optimal power generation.

Insufficient levels of either ingredient can result in reduced power output, causing the engine to feel sluggish.

What causes engine hesitation?

There are several common causes of engine hesitation, such as a dirty air filter, a stuck or failed mass airflow sensor (MAF), a clogged or leaking exhaust gas recirculation (EGR) valve, a failing ignition coil, a failing throttle position sensor (TPS), clogged fuel injectors, a dirty or clogged fuel filter, a failing oxygen sensor (O2), or a catalytic converter that is dirty.

Engine hesitation is a condition where the engine hesitates or stutters during acceleration. It can be caused by various factors mentioned above, and diagnosing the issue requires careful evaluation of these potential causes.

Why does my car lose power when accelerating?

The primary reason for a car losing power during acceleration is often due to a clogged fuel filter or engine air filter.

Another potential cause could be a damaged sensor, such as the MAF sensor or O2 sensor, which can disrupt the air-fuel mixture.

While these are frequent culprits for this issue, it is important to note that there are various other factors that could contribute to a loss of power under acceleration.

Why is my car idle surging?

While idle surging can also be attributed to other car problems, if it occurs alongside other symptoms of a faulty throttle position sensor, the TPS is often the cause.

There are six common symptoms associated with a faulty TPS, and the cost of replacing it varies depending on the specific vehicle.

Have you checked for any clogged or blocked fuel filters that may be causing engine stalling?

Common symptoms of a faulty fuel filter include engine misfire, engine stalling, foul odor from the exhaust system, and difficulty starting the engine. It is recommended to promptly inspect the fuel filter if any of these symptoms emerge. Fortunately, evaluating the condition of a fuel filter is a straightforward process.

What does a clogged fuel filter mean?

If the fuel filter is clogged, it may lead to inadequate fuel supply to the engine, resulting in several complications. Recognizing these symptoms could indicate a problem with the filter, which could be caused by age, dirtiness, or blockage. However, it is important to note that similar symptoms may arise from a faulty fuel pump or other causes. Proper fuel flow is essential for the engine to function properly.

Why is my engine stalling?

An engine can stall due to three main reasons: a lack of fuel, power, or air. It is not surprising that if there is insufficient fuel flowing, the engine can stall. Even if there is still fuel in the fuel lines, the engine may initially start without any issues.

Can a dirty fuel filter cause stalling?

A dirty fuel filter can result in decreased fuel pressure, leading to prolonged cranking before the engine starts. If your vehicle repeatedly stalls while driving or at low speeds, it may indicate a dirty fuel filter. Depending on the level of clogging, your car may start again without any noticeable decrease in power.

Can a clogged fuel filter make a car stutter?

When driving normally, a clogged fuel filter may not show any symptoms. However, during quick acceleration, the engine might not get enough extra fuel, leading to potential issues. Depending on the severity of the fuel restriction caused by a dirty filter, the engine may also experience shaking or stuttering at varying speeds.

Could a timing belt failure be causing the engine to stop while driving?

When the timing belt breaks while driving, there are some common signs such as loud noises, engine stalling, and potential internal damage.

The most frequently seen damage when this occurs is bent or broken valves, although other engine components such as the cylinder head, camshaft, and pistons can also be affected.

If your car has a non-interference engine, the pistons and valves are housed separately and therefore a broken timing belt will not cause damage to them.

There are several factors that can contribute to timing belt failure, including misalignment, excessive load, age and mileage, debris in the pulleys, and water pump seizure.

Can a timing belt break while driving?

If the timing belt breaks while driving, it can result in severe damage to the engine. The purpose of the timing belt is to ensure that the valves and pistons of the engine are synchronized. However, if the timing belt breaks, the valves and pistons will no longer be aligned, leading to potential collisions between them.

You can identify a faulty timing belt by observing certain symptoms, such as difficulty starting the engine, unusual engine noises, engine misfires, engine vibrations, or excessive exhaust smoke. In terms of replacement cost, it varies depending on the make and model of the vehicle, but it is generally a substantial expense.

How do I know if my timing belt is bad?

A bad or failing timing belt typically exhibits symptoms related to performance. These symptoms include engine misfires, power loss, and the presence of a ticking sound. Furthermore, the Check Engine Light may illuminate and there may be exhaust-related complications. In severe instances, the engine may fail to turn over entirely.

What is a timing belt & how does it work?

The timing belt is an essential internal component of an engine that synchronizes the rotation of the camshaft and crankshaft, ensuring proper timing of the cylinder firing. It is typically situated under a timing cover at the front of the engine.

A malfunctioning timing belt can exhibit various symptoms indicating its failure. To know if you have a bad or failing timing belt, it is recommended to consult with a professional mechanic.

Can a non-interference engine cause a timing belt failure?

If you have a non-interference engine and the timing belt fails, the piston will not collide with the valve, even when the engine is operating normally. As a result, the consequences of a timing belt failure in a non-interference engine are generally less severe than in an interference engine.

However, it is important to note that the specifics of what happens when a timing belt breaks while driving can vary depending on the make and model of the vehicle. Generally, the engine will simply stop running, and you will need to have the timing belt replaced in order to get the engine working again.

Is the engine overheating, potentially causing it to shut off as a safety measure?

A malfunctioning thermostat can lead to engine overheating, which in turn triggers the automatic shutdown of the AC system as a precautionary measure for safety.

Why is my engine overheating?

There are several potential reasons for engine overheating. It can occur when the cooling system is faulty, preventing heat from escaping the engine compartment. Possible causes include a leaking cooling system, a malfunctioning radiator fan, a defective water pump, or a blocked coolant pipe. It is crucial not to neglect an overheating engine, regardless of the underlying cause.

When a car overheats and shuts off, it can lead to various consequences. These can include damage to the engine such as warped cylinder heads or blown head gaskets. Other potential outcomes involve the transmission malfunctioning or the car's computer systems shutting down. Therefore, addressing an overheating engine promptly is essential to prevent further complications.

What should I do if my engine overheats?

If your engine is consistently overheating, it is advisable to consult a professional, such as a technician from Your Mechanic, for assistance. Once the leak is fixed, it is important to have your car inspected to ensure that there are no further causes of overheating other than the repaired leak. When experiencing overheating, it is recommended to turn off the air conditioning and find a safe place to pull over.

What happens if your engine thermostat is stuck open or closed?

The thermostat in your vehicle controls the opening and closing of the engine to maintain the correct temperature. When it becomes stuck in an open or closed position, it can cause significant engine problems. The thermostat is typically housed in a plastic casing on the engine block or head, and you can refer to your repair manual to locate it.

One potential reason for engine overheating is a broken water pump. If the water pump is not functioning properly, it can lead to insufficient coolant circulation, resulting in engine overheating.

Does coolant overheat a car?

The main function of coolant is to regulate the temperature of your engine by dissipating heat. Consequently, it is not surprising that if your vehicle has low or no coolant, your engine will overheat. It is important to note that your vehicle's cooling system is designed to be sealed, which means if you find yourself frequently adding coolant, it is crucial to identify the underlying issue causing the coolant loss.

If you are experiencing engine overheating, there are various potential reasons for this occurrence. Identifying and addressing these causes is vital in resolving the overheating problem. Mechanic Ba... provides a comprehensive guide outlining nine common reasons for engine overheating and offering advice on how to rectify the issue.

Is the car equipped with a fail-safe mode that might be triggering the engine to shut off in certain situations?

The engine fail safe mode can be activated by a sensor malfunction or an electrical error. It is also possible for a security system issue to activate this warning light, implying that it is not exclusively caused by a mechanical problem.

What causes failsafe mode on a car?

The Engine Failsafe Mode can be activated when various damaged transmission components are present, such as inner gaskets, seals, the torque converter, mechanical gears, the input shaft, or even a damaged flywheel or driveshaft.

Engine Failsafe Mode is a safety feature designed to protect the engine and transmission from further damage when these components are compromised.

If the Engine Failsafe Mode is activated, it is important to have the vehicle inspected by a mechanic to diagnose and repair the underlying issue.

What is engine safe-mode?

Engine Safe-mode acts as a support mechanism for your car, similar to crutches. It signifies that the OBD2 diagnostic system in your vehicle continuously monitors all vehicle systems. If the engine failsafe mode is triggered, it may be helpful to understand its explanation and learn how to reset it.

When the engine failsafe mode is activated, it indicates that the OBD2 diagnostic system is actively observing various components of the vehicle.

Why is a fail-safe engine control system important?

The importance of functional safety for automakers cannot be disregarded.

Currently, vehicles are equipped with a fail-safe engine control unit architecture, which detects faults and transitions the system to a safe state.

However, it still allows the driver to retain control of the vehicle in the end.

Have you checked the fuel pump to ensure it is functioning properly and providing adequate fuel pressure?

To test fuel pumps for pressure, one can install a fuel pressure gauge, run the pump, and note the pressure reading. It is important to compare the pressure reading to the manufacturer's specification. If the pressure is below the required level, it is necessary to address the problem. If the fuel pump is providing sufficient pressure, a fuel volume test should be conducted to ensure the proper amount of fuel is being delivered to the fuel injectors.

When performing a fuel pressure test, locate the service cap on the fuel rail, typically near the fuel injectors. Remove the cap to reveal a Schrader valve where the fuel pressure gauge can be connected. Turn the ignition key to the on position and check the reading on the gauge, which should be between 45 psi and 60 psi.

Refer to the vehicle's fuel pressure specifications and connect a gauge to check the pressure with the key on and engine off, as well as with the engine running. If the pressure does not meet the specifications, further diagnosis is required. Additionally, the volume of fuel delivered by the fuel pump to the injectors is critical.

To test the fuel pump's fuel delivery, isolate the pump near the fuel injector rail and pressurize the system. During this test, no fuel pressure should reach the injectors or the pressure regulator. If the fuel line pressure quickly drops to zero, it indicates a leak either through the fuel pump check valve or a fuel line fitting.

How does a fuel pressure sensor work on a fuel pump?

The device utilizes data from various sensors, such as the fuel pressure sensor and fuel temperature sensor, to analyze and regulate the pump's ground circuit and adjust the pump's speed.

It is advisable to thoroughly inspect and verify the functionality of all components within the control system before attributing any issues to the fuel pump.

What is a fuel pump control module?

In newer fuel systems, the fuel pump control module (FPCM) is responsible for directly controlling the fuel pump.

Diagnosing a faulty fuel pump can be done by following a few steps. By checking for common symptoms, such as engine sputtering or difficulty starting, and performing tests using a fuel pressure gauge, the issue can be accurately identified. It is important to consult the vehicle's manual or seek professional assistance for a thorough diagnosis and repair.

Why do I need to test my fuel pressure gauge?

It is recommended to conduct additional testing to eliminate the possibility of fuel pump circuit problems and other issues that could restrict the supply of fuel, such as a clogged fuel filter or faulty pressure regulator.

However, it is crucial to exercise caution and follow proper procedures outlined in the repair manual to relieve fuel system pressure before connecting a fuel pressure gauge.

For more detailed instructions on diagnosing a faulty fuel pump, you can refer to the article "How to Diagnose a Faulty Fuel Pump" on the Car Parts blog.

How do you check a fuel pump pressure?

Start the engine and record the pressure reading.

It is advisable to refer to the manufacturer's specifications on pressure testing the fuel pump.

Many manufacturers suggest checking the pressure with the key on, engine running, and at a designated RPM.

Proceed to step 8 and check for the appropriate pressure.

For detailed instructions on how to check a car fuel pump, visit YourMechanic Advice's article "How to Check a Car Fuel Pump".

Could a malfunctioning engine control module (ECM) be causing the engine to stall while driving?

Symptoms of a defective Engine Control Module (ECM) typically include the illumination of the check engine light on the dashboard. The vehicle may also experience engine performance problems such as misfiring or stalling. Furthermore, there may be issues with shifting gears or applying power, resulting in a sensation of awkward, delayed, or jarring shifts. In some cases, the engine may intermittently become more active or stall. Additionally, the car may fail to start altogether.

What happens if the engine control module (ECM) fails?

The engine control module (ECM), also known as the engine control unit (ECU), serves as a crucial component. It is responsible for sending necessary instructions to the motor in order to maintain optimal performance. However, when the ECM begins to malfunction, it presents several indicators of a potential issue.

There are five common signs that indicate a faulty engine control module, including engine misfires, issues with starting the vehicle, reduced fuel efficiency, irregular engine performance, and illuminated warning lights on the dashboard. In such cases, it becomes necessary to replace the ECM in order to restore proper functionality.

Why does my engine burn more fuel if the ECM is bad?

A faulty Engine Control Module (ECM) can result in improper regulation of fuel intake, leading to increased fuel consumption. Monitoring your fuel economy can help identify this issue early on.

Here are five signs that indicate a malfunctioning ECM and the potential cost of replacing it.

How do I know if my engine control module is bad?

One indication of a bad engine control module (ECM) is experiencing engine performance problems such as misfiring or stalling.

If your car is not starting at all, it could be another indication that your ECM is faulty.

What does the ECM do in a car?

The Engine Control Module (ECM) is a critical component that serves as the primary computer for various engine performance and drivability tasks in a vehicle.

If there are any issues with the ECM, it can result in various symptoms that may indicate a faulty or failing module.

Reviewed & Published by Albert

Submitted by our contributor

Driving Category