Whenever an unfortunate incident occurs, a stalled car engine can quickly become a stressful endeavor. It can be even more distressing if the engine stalls while you’re driving because it is not only an extreme safety hazard, but it can also end up leaving you stranded on the side of the road.
If your engine is stalling, you need to address the situation as soon as possible. The first step is knowing and understanding the causes of a stalled engine.
There are several reasons why your motor may stall, and this guide will explain in detail some of the most common causes.
What Does it Mean When a Car Stalls?
The term “stalling” is used to describe the sudden loss of power to a vehicle’s operating systems. Stalling can happen for several reasons, some of which are mechanical in scope, while others are electrical.
In some cases, a vehicle will restart without issue after stalling. However, at other times, a vehicle may crank to no avail.
In any event, vehicle stalling is cause for immediate concern and should be addressed as soon as possible. If stalling were to take place at cruising speeds, one’s safety could be compromised.
#1. Fuel System Issues.
Fuel system issues can be a significant cause of a car stalling, especially when the engine is not receiving an adequate supply of fuel. When the fuel tank is empty or nearly empty, the car stalls as the engine lacks the necessary fuel to sustain combustion. This scenario often occurs when drivers overlook the fuel gauge or miscalculate their remaining fuel, leading to an unexpected inconvenience.
Moreover, a malfunctioning fuel pump can also contribute to the car stalling. The fuel pump is responsible for pumping fuel from the tank to the engine, and if it fails, the engine won’t receive the required fuel, resulting in the car stalled situation. This issue can manifest while driving, causing potential safety concerns and necessitating immediate attention.
In some cases, the car stalling may be linked to fuel injection problems. Issues such as clogged fuel injectors or a malfunctioning fuel pressure regulator can disrupt the proper delivery of fuel to the engine, leading to erratic combustion and stalling.
#2. Charging System Issues.
Once a vehicle starts, engine and component operation is sustained through the delivery of an engine’s charging system voltage. The most critical component within this system is a vehicle’s alternator, which generally provides 13.5-14.5 volts under normal operation.
However, a faulty alternator can provide significantly less voltage, leading to rapid battery discharge. Such discharge can lead to vehicle stalling in short order, even with a relatively new battery.
#3. Ignition Problems.
Ignition problems can be a major culprit behind a car stalling or experiencing sudden loss of power while driving. The ignition system is responsible for generating the spark that ignites the air-fuel mixture in the engine’s cylinders. If any component of the ignition system malfunctions or fails, it can disrupt this process and result in a car stall.
One common ignition problem that can cause a car to stall is a faulty ignition coil. The ignition coil is responsible for generating the high voltage needed to create a spark. If the ignition coil fails or becomes weak, it may not be able to produce a strong enough spark to ignite the fuel mixture consistently, resulting in engine misfires or a complete car stall.
Another possible issue is worn-out or faulty spark plugs. Spark plugs play a crucial role in creating the spark that ignites the fuel-air mixture. Over time, spark plugs can become fouled or worn, leading to weak or inconsistent sparks. This can cause misfires, rough idling, or even a car stall while driving.
If you are experiencing frequent stalling issues with your car and wondering, “Why is my car stalling?” it is recommended to have a qualified mechanic inspect your ignition system.
#3. Sensor Malfunctions.
If there’s nothing wrong with your car mechanically, the fault could lie in one of the dozens if not hundreds of sensors scattered throughout your vehicle. The car’s brain, the ECU, relies on data from these sensors to control the engine and prevent catastrophic engine damage.
The most common sensor that can lead to your car stalling is the manifold absolute pressure sensor (MAP) or the mass air flow sensor (MAF). Most cars typically have one or the other.
It’s the MAP/MAF sensor’s job to measure the air density entering the engine and calculate how much fuel should be used to provide the optimal fuel-to-air mixture based on that data. If this sensor fails or provides inaccurate data, the ECU can make the fuel/air mixture too lean or too rich, causing ineffective combustion and a stalling engine.
Other sensors which could potentially cause your vehicle to stall include the engine coolant temperature sensor and the throttle position sensor which measures the position of the accelerator pedal.
Although slightly less common, a faulty crankshaft or camshaft sensor could also lead to your car stalling, both while driving and when stationary. Additionally, certain issues related to the idle air control valve (IAC) or the throttle body itself can be the reasons behind stalling the engine.
#4. Electrical Problems.
Electrical problems can be a significant cause of a car stalling or experiencing sudden engine shutdown while driving. The electrical system in a car is responsible for powering various components and ensuring their proper functioning. If there is a fault or malfunction in the electrical system, it can disrupt critical processes and lead to a car stall.
One common electrical problem that can cause a car to stall is a malfunctioning alternator. The alternator is responsible for generating electrical power and charging the battery while the engine is running. If the alternator fails or doesn’t provide enough power, it can lead to a drained battery. As a result, the car may stall while driving due to a lack of electrical power.
Another cause of car stalling can be a faulty ignition switch or ignition wiring. The ignition switch controls the electrical power supply to various components, including the ignition system.
If there is a problem with the switch or the wiring that connects it, it can cause intermittent loss of power to the ignition system. This can lead to misfires, engine shutdown, or a complete car stall.
#5. Air Intake Issues.
Air intake issues can contribute to a car stalling, creating a frustrating situation for drivers who may wonder, “Why is my car stalling?” The air filter is a critical component in the air intake system, responsible for filtering out impurities and ensuring clean air reaches the engine for combustion.
Over time, the air filter can become clogged with dirt and debris, restricting the airflow. This restriction can disrupt the proper air-fuel mixture, leading to incomplete combustion and the engine stalling.
In addition to air filter issues, problems with the throttle body can also contribute to car stalling. The throttle body regulates the amount of air entering the engine. If it becomes dirty or experiences carbon buildup, it can impede the airflow, affecting the engine’s performance.
In such cases, the car may stall, particularly during acceleration or deceleration. Throttle body issues can create an imbalance in the air-fuel mixture, causing the engine to run unevenly and potentially leading to a car stalled scenario.
#6. Exhaust Issues.
The exhaust system plays a vital role in guiding exhaust gases out of the engine, maintaining engine performance, and reducing emissions. If there are any issues with the exhaust system, it can disrupt proper engine operation and lead to stalling.
One potential exhaust issue that can cause a car to stall is a clogged catalytic converter. The catalytic converter is responsible for converting harmful gases into less harmful emissions.
However, over time, the converter can become clogged due to the accumulation of carbon deposits or other substances. A clogged catalytic converter restricts the flow of exhaust gases, reducing engine performance and potentially causing the car to stall.
#7. Transmission Problems.
Transmission problems can significantly contribute to a car stalling, introducing a layer of complexity to the driving experience.
In the case of manual transmissions, issues with the clutch can lead to the car stalling, especially during gear changes or when coming to a stop. A slipping or worn-out clutch may fail to engage or disengage properly, causing the engine to stall abruptly.
Drivers may notice the car stalled situation as they try to shift gears or navigate through traffic, making it evident that the transmission-related problem is impacting the vehicle’s overall performance.
In automatic transmissions, torque converter problems can also result in the car stalling. The torque converter is a critical component that allows the transmission to transfer power from the engine to the wheels. If the torque converter fails to operate correctly, it can disrupt this power transfer, leading to stalling episodes.
#8. Vacuum Leaks.
Some cars and car systems rely on vacuum to perform their job effectively and as intended. When discussing a vacuum leak, people usually refer to a leak in the intake manifold that brings in more air than the engine can handle or is prepared for.
As you can imagine, an air leak will cause the car to run lean, which means that the mixture inside the engine doesn’t have enough fuel in it to combust as intended. Vacuum leaks are most noticeable at startup, especially in colder climates, where your car wants to run rich for the first few minutes until it gets up to temperature.
Vacuum leaks will give symptoms such as engine misfire, delayed acceleration, and most notably, an extremely rough and choppy idle. All of these symptoms could lead to stalling provided the leak is large enough.
#9. Lockup Of Belt-Driven Accessories.
The sudden failure of belt-driven accessories can also lead to vehicle stalling. When such components, such as an A/C compressor or power steering pump lock up, resistance is placed upon an engine’s drive belt.
If the belt itself does not snap, excessive resistance will also be placed upon the engine’s crank pulley. This, in turn, can smother an engine out, putting it into a stall in the process.
#10. Timing Issues.
The vast majority of today’s internal combustion engines feature timing chains or timing belts. These belts/chains synchronize the timing between the engine’s crankshaft and top-end components.
If a timing chain or belt were to stretch or break, an engine’s timing can shift, causing a stall. In the most extreme cases, the breakage of a timing belt or chain can lead to severe internal engine damage.
What Should You Do If Your Car Stalls While Driving?
If your car were to stall while driving, the first order of business would be to remain calm. Though panicking would seem natural in such a situation, keeping your composure is key to bringing a misadventure of this type to a safe resolution.
When stalled, a vehicle loses all power steering and power braking, meaning that both functions must be completed through manual force. Begin applying your vehicle’s brakes at a steady, yet reasonable rate. Over-braking will induce a skid, thereby further complicating matters.
You should also look for a safe place to pull over, which in most cases will include the shoulder of the roadway. After checking to ensure that it is safe to do so, carefully merge over onto the shoulder of the road, while using your vehicle’s turn signal. Upon reaching the shoulder, continue braking until your vehicle comes to a complete stop.
Once stationary, place your vehicle in park (automatic) or neutral (manual) and set the emergency brake. If the source of your vehicle’s stalling condition can not be easily identified and repaired roadside, call a wrecker to have your vehicle transported to a service facility.
Does Stalling a Manual Transmission Car Damage It?
Many who are new to driving a vehicle with a manual transmission, deal with difficulties when attempting to take off at a stoplight, or when easing into a parking spot in reverse. If the correct amount of throttle/clutch is applied, a vehicle of this nature will stall, requiring a restart.
The question is, does stalling a manual transmission cause damage. The short answer to this question is “no”. While stalling a manual transmission is certainly not ideal, it is unlikely to cause any notable damage, unless done repeatedly over several years.
At worst, repeated stalling might finish off aging components within the driveline that are already approaching the point of failure. However, most drivers will master the use of a manual transmission far before any damage can be sustained.
What to Do When Your Vehicle Stalls on the Highway
A vehicle stalling on any street can be scary, but the immediate danger is much greater on a highway where traffic could be moving at high speed around your vehicle. A few basic tips can potentially help you avoid a crash and minimize damage to your vehicle:
- When your car stalls, you will have a few seconds before the engine shuts down completely and you cannot control the vehicle. Quickly but carefully move to the right as far as possible, ideally onto the shoulder if it is safe to do so.
- Engage your vehicle’s hazard lights to warn drivers behind you that you are having problems with your vehicle.
- Once your vehicle is stopped, make sure your hazard lights remain engaged.
- If you can reach the side of the road, only leave your vehicle through the passenger door. Do not step out of your driver’s door or open the driver’s door into passing traffic. If your vehicle is stuck in the middle of the highway, do not leave your vehicle.
- Call for help as soon as possible. If your vehicle is stuck in the middle of the highway you should call 911 so first responders can help you get out of the way of passing traffic as quickly as possible. If you’re able to move out of active traffic, call a towing service.
- If you successfully pull your vehicle onto the shoulder, do not attempt to fix the problem with your engine unless you know what you are doing.
Hopefully, these tips can help you avoid experiencing an accident after your vehicle stalls on the highway. Unfortunately, there is no way to predict how other drivers will react to your vehicle stalling or whether passing drivers are paying attention to their surroundings.
If an accident occurs after your vehicle has stalled on the highway, you will likely need to consult an attorney to determine the best way to recover your damages.