Car Engine Turns Off When Idle

Causes

There are several potential causes for a car engine to turn off when idle, including:

Idle air control valve (IACV) failure: The IACV is responsible for controlling the amount of air that enters the engine when it is idling. If the IACV fails, the engine may not get enough air to idle properly and will stall.
Vacuum leak: A vacuum leak can cause the engine to run lean, which can lead to stalling. Vacuum leaks can be caused by a variety of factors, such as a cracked or loose vacuum hose, a faulty intake manifold gasket, or a damaged EGR valve.
Fuel system problems: Fuel system problems, such as a clogged fuel filter or a faulty fuel pump, can also cause the engine to stall. If the fuel system is not delivering enough fuel to the engine, it will not be able to idle properly.
Electrical problems: Electrical problems, such as a loose or corroded electrical connection, can also cause the engine to stall. If the electrical system is not functioning properly, it may not be able to provide the power necessary to keep the engine running.

Diagnosis

To diagnose the cause of a car engine that turns off when idle, a mechanic will typically start by checking the IACV. If the IACV is faulty, it will need to be replaced. If the IACV is not the cause of the problem, the mechanic will then check for vacuum leaks. Vacuum leaks can be found by using a smoke machine or by spraying a carburetor cleaner around the intake manifold. If a vacuum leak is found, it will need to be repaired.

If the IACV and vacuum leaks are not the cause of the problem, the mechanic will then check the fuel system. The fuel filter will be inspected for clogs, and the fuel pump will be tested to ensure that it is delivering enough fuel to the engine. If the fuel system is not the cause of the problem, the mechanic will then check the electrical system. The electrical system will be inspected for loose or corroded connections, and the battery will be tested to ensure that it is providing enough power to the engine.

Repair

The repair for a car engine that turns off when idle will depend on the cause of the problem. If the IACV is faulty, it will need to be replaced. If there is a vacuum leak, it will need to be repaired. If there is a fuel system problem, it will need to be repaired or replaced. If there is an electrical problem, it will need to be repaired.

Prevention

There are several things that can be done to prevent a car engine from turning off when idle, including:

Regular maintenance: Regular maintenance, such as oil changes and tune-ups, can help to keep the engine running properly and prevent problems from developing.
Inspecting the IACV: The IACV should be inspected regularly for signs of wear or damage. If the IACV is faulty, it should be replaced.
Checking for vacuum leaks: Vacuum leaks can be checked by using a smoke machine or by spraying a carburetor cleaner around the intake manifold. If a vacuum leak is found, it should be repaired.
Inspecting the fuel system: The fuel filter should be inspected regularly for clogs, and the fuel pump should be tested to ensure that it is delivering enough fuel to the engine. If the fuel system is not functioning properly, it should be repaired or replaced.
Inspecting the electrical system: The electrical system should be inspected regularly for loose or corroded connections, and the battery should be tested to ensure that it is providing enough power to the engine. If the electrical system is not functioning properly, it should be repaired.

By following these tips, you can help to prevent your car engine from turning off when idle and keep your car running smoothly.