Automatic cars have been a boon to the motor world. They have made driving easier for everyone out there. They are easy to run and operate, but because they are quite new in the market, not much information is available for their issues. You must be aware of some reasons why a manual transmission car stalls, but what if you are running an automatic car? Having your car stalled in the middle of a red light or speed breaker can be an embarrassing situation for sure. If you are still thinking about why your automatic car stalls, this oneHOWTO article is going to give you detailed information on the rest of the symptoms you'll notice depending on the source of the problem, so that you can get it fixed accordingly.
Problem with the torque converter
An automatic car has a torque converter which serves as a replacement for the mechanical clutch of a manual transmission car. The purpose of a torque converter is to unlock while accelerating or decelerating. Sometimes, braking takes place even before the torque converter is asked to do it, due to which the engine loses power and stalls.
Signs of a bad torque converter
- Check your temperature gauge as your car may also be overheating
- It starts to stall when you accelerate over 30 MPH
- Clicking noise
What to do?
If you have determined that this is the problem, it's best you take it to a trusted mechanic as soon as possible so he/she can fix the problem.
Dirty air flow sensor
A dirty or malfunctioning air flow sensor can be responsible for the stalling of your automatic car. An automatic car has several sensors that are responsible for sending relevant information to the vehicle’s computer system. The air flow sensor is designed to monitor the quantity and quality of air entering the car’s engine. With this information, the engine is able to determine how much fuel should be used. If your car’s sensor has become dirty or faulty, then it will give incorrect information to the car’s engine, thus causing the car to stall while idling.
How to know if you have a dirty air flow sensor
- Car stalls when idling
- The engine light may be on
- Check your car's computer through a mechanic's digital car diagnosis scanner
What to do?
If that’s the reason for your car stalling, it is better to get it cleaned, fixed or replaced as soon as possible.
Issue with the idle circuit
An automatic car has an idle circuit that is used to control air that circulates during idling. If the idle circuit stops working properly, then the car will not receive the right amount of oxygen required for operation. In that case, the car stalls due to non-combustion of the fuel.
How to know if there's a problem with the idling circuit
- Your engine will run roughly
- Your car doesn't stall at a high speed
What to do?
As there are different causes for this, you should further asses the idle circuit to find the source of the problem.
Clogged air control valve
The air control valve in your automatic car is responsible for allowing just the right amount of air to enter into your car’s engine. In other words, it works as an air regulator to help the engine keep running properly. But sometimes, carbon may build up on this air control valve, due to which it stops working properly and sends incorrect amount of air into your car’s engine.
How to know if the air control valve is clogged
If this happens, your car will start stalling at red lights and speed breakers.
How to fix it
You can clean or replace it to let it work as required.
Malfunctioning oxygen sensor
Automatic cars have an oxygen sensor that monitors the oxygen level of the air being pushed out. Sometimes, this sensor does not work properly and the car stalls because it cannot understand that there is a lack of oxygen required for combustion.
How to know if your oxygen sensor is malfunctioning
- Your engine light will come on
- Your car's mileage will be significantly reduced
- Your engine may misfire
How to fix it
In this case, you should replace the sensor or take it to a professional so he or she can do so.
Stale fuel
If the fuel inside your car has gone stale, or if it has higher ratio of water inside it, then it becomes more difficult for the car’s engine to achieve combustion. Sometimes, the octane rating of your car’s fuel also plays a role in causing your automatic car to stall. The octane level in your car’s fuel is responsible for determining how hot it will burn.
How to know if fuel is stale
- Your octane level will not be hot enough.
- Your engine won't run as well as it used to and may not start
How to fix it
Use an ethanol stabilizer, though it is best if you let a professional do so.
Worn out spark plugs
Automatic cars have spark plugs to send electric currents to the engine. If your plugs have worn out, the flow of electric current will get disrupted and your car will misfire or stall during operation.
How to know if your spark plugs are worn
- Your car will overheat
- You will notice oil seeping in the spark plugs
- Your injectors will be dirty
How to fix it
If this is the reason for your automatic car stalling, then it is advised to get them replaced immediately.
If you want to read similar articles to Why Does my Automatic Car Stall, we recommend you visit our Car Maintenance and Repair category.