Whenever something unfortunate happens, dealing with a stalled car engine can quickly become a stressful undertaking. It can be even more stressful if the engine stalls while you are driving because not only is it an extreme safety hazard, but you could potentially be stranded on the side of the road.
If your engine is stalling, you need to act quickly. The first thing you need to do is to know and understand what could be the cause of a stalled engine.
There are various reasons why your motor could stall, and this guide will discuss in detail some of the most common causes.
What Does it Mean When a Car Stalls?
“Stalling” means a sudden loss of power to the vehicle’s operating systems. A vehicle can stall for many reasons, some mechanical in nature, others electrical.
In some cases, a vehicle will start right up again after stalling, and in others, the engine cranks but nothing else happens!
Regardless of the particular circumstances, vehicle stalling is a real problem that should be solved as soon as possible. If a vehicle were to stall while traveling at speed, you may put your safety at risk.
#1. Fuel system problems.
Fuel system problems can be a big contributor to a car stalling, particularly when the engine does not receive a sufficient supply of fuel. When the gas tank is empty or nearly empty, for example, the car stalls because the engine cannot receive any fuel to continue the combustion cycle.
This often happens when a driver simply forgets to check the gauge or miscalculates their remaining fuel level, which leads to an inconvenient situation.
Moreover, an bad fuel pump can also cause a car to stall. The function of the fuel pump is to pump fuel from the tank to the engine, and if the fuel pump is bad – the engine will not receive the fuel to operate, leading to the car stalling. The car can stall in many ways while driving, which presents a safety problem and requires timely action.
Sometimes the stalling situation may relate the fuel injectors and/or fuel pressure regulator. Fuel injectors can become clogged and/or a faulty fuel pressure regulator can prevent fuel from being sent to the engine properly, which results in inconsistent combustion and causes the engine to stall.
#2. Charging System Issues.
Once a vehicle has started, the operation of the engine and its components continues using voltage supplied by the vehicles charging system .The charging system consists of different components using the alternator which on average produces 13.5-14.5 volts.
If the alternator fails it may produce a much lower voltage, which will cause the battery to drain, something that could contribute to the car stalling all together, even if its not an old battery.
#3. Ignition Problems.
Ignition issues can also be a major contributor to a car losing all power or stalling when driving. The ignition system is responsible for producing the spark needed to ignite the air-fuel mixture inside the cylinders of your engine, so if any part of the complete ignition system is neglected or not functioning, then that may interrupt the ignition process and result in a stall.
For example a faulty ignition coil is an ignition issue that can stall a car. The ignition coils are needed to produce the high voltage to create the spark. If the ignition coil is not working correctly, or is weak, it can potentially deliver not enough voltage to create a strong enough spark to ignite the fuel mixture and may lead to misfires and/or a full stall of the car.
Another ignitions issue could be faulty or older spark plugs. Spark plugs are the part of the ignition system that create the spark to ignite the fuel-air mixture. Spark plugs can wear down and become old or fouled and lead to weak or inconsistent sparks. Weak or inconsistent sparks can cause misfires, rough idling and even a stall while driving.
If you are experiencing intermittent stalling symptoms and asking yourself, “why is my car stalling?”, it would be a good idea to have a certified mechanic inspect your ignition system.
#4 Sensor Malfunctions.
If there is nothing wrong with your car mechanically, it is possible that the fault is with one of the dozens, if not, hundreds of sensors that are all over your vehicle. The car’s brain, the ECU, controls the engine based on input from those sensors, it uses the input from those sensors to prevent catastrophic damage to the engine.
The most common sensors that can cause a car to stall are the manifold absolute pressure sensor (MAP) or the mass air flow sensor (MAF). Most cars have either one or the other.
The MAP/MAF sensor measures the density of the air that is flowing into the engine and determine how much fuel to use to provide the best fuel-to-air mixture based on that information.
If this sensor fails or provides faulty information, the ECU can make the fuel/air mixture is either too lean or too rich, and this can cause poor combustion causing an engine stall.
Other sensors that can cause your vehicle to stall are the engine coolant temperature sensor and the throttle position sensor, which reads the accelerator pedal position.
While not very common, a faulty crankshaft or camshaft sensor could also cause your car to stall, while in motion or at rest. Also, issues with the idle air control valve (IAC) or sometimes the throttle body itself can be the reason for stalling the engine.
#5. Electrical Issues.
Electric issues can be a major cause of a car stalling, or abruptly shutting off while you are driving. The electrical system of your car is responsible for powering your cars systems and allowing them to function. If there is a fault in the electrical system or the electrical system is simply malfunctioning, various, critical processes can be disrupted and cause a car stall.
One possible electrical issue that would cause the car to stall could be a malfunctioning alternator. The alternator is responsible for generating electrical power and charging the battery, while the engine is running.
In some cases, the alternator can fail or is unable to generate enough power which results in a drained battery, leading to the car stalling while driving due to a lack of electrical power.
A second potential electrical issue that can lead to car stalling is caused by a faulty ignition switch or ignition wiring. The ignition switch controls the factory-supplied electrical power being sent to the necessary vehicle components; with the ignition switch first connecting electrical power to the ignition system.
If there’s any problem with the ignition switch or the wiring attached to the ignition switch, it could potentially cut electrical power to the ignition system intermittently. The intermittent lack of power to the ignition system could create misfires, engine shutdown, or total car stalls.
#6. Air Intake Issues.
Air intake, however one of the contributors to a car stalling, creating an outright frustrating experience for drivers asking, “Why is my car stalling?” The air filter is a major component in the air intake system and is responsible for filtering out impurities to ensure clean air makes it to the engine for combustion purposes.
Over time, dirt and debris can clog the air filter and restrict airflow to the engine. This is especially true if the engine is warm or hot. The restriction will disrupt the proper air-fuel mixture balance, and when the engine receives an improper air-fuel mixture that leads to incomplete combustion, it could stall the engine.
Aside from the air filter issue, a related issue tied to air intake to a car stalling can be associated with the throttle body. The throttle body controls the amount of air admitted to the engine, When there is an issue with the throttle body dirty/throttle body carbon buildup up it can impede airflow, therefore disrupting performance.
If this air restriction is too great it can lead to the car stalling while accelerating or decelerating. A problem with the throttle body can also create an imbalance of the air-fuel mixture that creates uneven engine running which can equally contribute to a car stalled condition.
#7. Exhaust Issues.
The exhaust system is important for directing exhaust gases from the engine, achieving engine performance, and reducing emissions. Any problem with the exhaust system will affect how the engine operates properly, which could stall the engine.
A contamination problem with the exhaust system that can stall a car is a clogged catalytic converter. The catalytic converter converts harmful gases into harmful emissions.
However, over time, the catalytic converter becomes contaminated with carbon deposits or other matter and becomes clogged, restricting the exhaust gas emission, reducing engine performance, and can stall the car while in operation.
#8. Transmission issue.
A transmission issue can greatly be responsible for a car stall, adding a layer of difficulty to the general driving experience.
For instance, manual transmissions have a clutch that, when failing, can stall the car, especially while changing gears or coming to a stop. A slipping or worn clutch may fail to engage or disengage and stall the engine abruptly.
For the vehicle operator, when their car stalls may become evident while they are trying to change gears or maneuvering through traffic, signifying that the cause of the stall may be related to the vehicle’s transmission.
In automatic transmissions, a problem with the torque converter will stall the vehicle. The torque converter is an important assembly and part of the drive train which allows the transmission to transfer power from the engine to the wheels of the vehicle. When the torque converter ceases to function properly its power transfer or stall every so often.
#9. Vacuum leaks.
Some vehicles and vehicle systems operate using vacuum to carry out their task in an appropriate manner. When people talk about a vacuum leak, they are usually talking about a leak in the intake manifold that allows more air into the engine than it can process, or is ready for.
As you can guess, a source of air will cause the car to run lean, and the mixture inside the engine to lack sufficient fuel to combust. A vacuum leak is detected most readily at startup, specifically in colder climates, where your car wants to run rich for the first few minutes until it gets up to temperature.
Vacuum leaks will provide symptoms like engine misfire, delayed acceleration, and most noticeably, an extremely choppy and rough idle. Any of these symptoms could result in a stall, depending on the size of the vacuum leak.
#10. Lockup of belt-driven accessories.
Sudden failure of belt-driven accessories can also cause vehicles to stall. For example, if an A/C compressor or power steering pump suddenly locks up, the engine’s power belt suddenly has additional resistance added.
If the power belt doesn’t even break, excessive resistance will also be added to the crank pulley of the engine, that can also suffocate and stall the engine.
#11. Timing Issues.
Most internal combustion engines in use today use either a timing chain or a timing belt. Timing belts and chains synchronize the timing of the crankshaft of the engine and top-end engine components.
If the timing chain or belt was to either stretch or break, the timing of the engine could change and could therefore stall the engine. While seems severe, breaking the timing belt could also result in severe internal damage to the engine as well.
What To Do If Your Vehicle Stalls While Driving?
If your car stalls while driving, the first response is to remain calm. Though panicking might seem a reasonable response, remaining calm will help you make your misadventure as safe as possible.
The disadvantages of driving a stalled vehicle are that it loses power steering and power brake assistance, which means that you must perform these functions manually. Apply your brakes at a steady but reasonable rate. Overbraking will induce a skid, resulting in you complicating the situation even more.
In addition, the decision of where to pull over safely will usually involve trying to maneuver to the shoulder of the road. Once you have determined that it’s safe to pull over, signal and carefully merge over onto the shoulder.
Continue to merge over until you have moved completely onto the shoulder of the road. Then continue braking until you have brought your vehicle to a stop.
Once stopped, place your vehicle in park (automatic) or neutral (manual), and set the emergency brake. If the cause of the vehicle’s stalled condition cannot easily be identified and repaired at the roadside, call a wrecker to have your vehicle removed to a repair shop.
Does Stalling a Manual Transmission Car Damage It?
Many new drivers with a manual transmission experience issues trying to take off at a stoplight or trying to ease into a parking spot in reverse. If the driver does not get the right balance of throttle and clutch application, the vehicle will stall which will need to be restarted.
So, does it damage a manual transmission vehicle to stall? The short answer to this question is no. The reality is that stalling a manual transmission is not ideal, but it will not likely cause any significant damage, unless it is being done repeatedly over the years.
At worst, repeating stalling may finish off some aging driveline components that were already at or near their end of life. But most drivers will learn how to properly use their manual transmission long before they can cause any damage.
Vehicle Stalls on the Highway: What to Do
There are few things as scary as a vehicle breakdown, but when that stall occurs on the highway, your chances of disaster increase due to the volume and velocity of traffic passing your vehicle. A few key tips can help you avoid a crash and lessen damage to your vehicle:
- If your vehicle stalls, you have a few seconds before the engine completely shuts off and you lose all control of the vehicle. Move your vehicle carefully, but quickly to the extreme right-hand side of the roadway to the shoulder position, if possible.
- When your vehicle is about to stall, turn on your hazard lights to warn approaching vehicles that you have a malfunction.
- After stopping your vehicle, ensure that you keep your hazard lights activated.
- If you manage to move your vehicle to the side of the roadway, exit using the passenger doors only. Do not exit using the driver’s side door and avoid opening the driver’s side door into oncoming traffic. If you are in the middle of the highway and can safely move your vehicle to a shoulder lane, do not exit your car.
- Call for help. When your vehicle is disabled in the middle of a highway, call 911 so that first responders can assist you out of harm’s way of the oncoming vehicles. If you are able to move your vehicle out of the active roadway, call a tow service to assist you with your broken vehicle.
- After moving your vehicle to safety on the shoulder space, do not attempt to repair any additional engine problems unless you know what you are doing.
Use these tips to avoid an accident due to the car stalling on a busy highway. There is no way to predict what other drivers may do after you have stalled out (or if they will even see you).
If an accident occurs after your vehicle has stalled on the highway, you may have a case and need to hire an attorney. An attorney can assist you in recovering your damages, and best proceed in your case.