Car Engine Revs When Started
What is Engine Revving?
Engine revving is when the engine speed increases rapidly, usually when the car is in neutral or park. It can be caused by a number of factors, including:
* A faulty idle air control valve
* A vacuum leak
* A throttle position sensor problem
* A problem with the fuel injection system
Symptoms of Engine Revving
The most common symptom of engine revving is a rapid increase in engine speed when the car is in neutral or park. Other symptoms can include:
* A rough idle
* Stalling
* Poor acceleration
* Increased fuel consumption
Causes of Engine Revving
There are a number of potential causes of engine revving, including:
* **A faulty idle air control valve:** The idle air control valve is responsible for controlling the amount of air that enters the engine when it is idling. A faulty idle air control valve can cause the engine to idle too high or too low, which can lead to revving.
* **A vacuum leak:** A vacuum leak can cause the engine to run lean, which can lead to revving.
* **A throttle position sensor problem:** The throttle position sensor tells the engine how much fuel to inject. A faulty throttle position sensor can cause the engine to inject too much or too little fuel, which can lead to revving.
* **A problem with the fuel injection system:** A problem with the fuel injection system can cause the engine to misfire, which can lead to revving.
Diagnosis of Engine Revving
The first step in diagnosing engine revving is to check the idle air control valve. If the idle air control valve is faulty, it will need to be replaced.
If the idle air control valve is not faulty, the next step is to check for a vacuum leak. A vacuum leak can be caused by a number of things, including:
* A cracked or loose vacuum hose
* A faulty intake manifold gasket
* A faulty EGR valve
If a vacuum leak is found, it will need to be repaired.
If the idle air control valve and the vacuum system are both functioning properly, the next step is to check the throttle position sensor. The throttle position sensor can be tested using a multimeter. If the throttle position sensor is faulty, it will need to be replaced.
If the idle air control valve, the vacuum system, and the throttle position sensor are all functioning properly, the problem may be with the fuel injection system. The fuel injection system can be tested using a fuel pressure gauge. If the fuel injection system is faulty, it will need to be repaired.
Treatment of Engine Revving
The treatment for engine revving depends on the underlying cause. If the problem is caused by a faulty idle air control valve, the idle air control valve will need to be replaced. If the problem is caused by a vacuum leak, the vacuum leak will need to be repaired. If the problem is caused by a throttle position sensor problem, the throttle position sensor will need to be replaced. If the problem is caused by a problem with the fuel injection system, the fuel injection system will need to be repaired.
Prevention of Engine Revving
There are a number of things that can be done to prevent engine revving, including:
* Keeping the idle air control valve clean
* Checking the vacuum system for leaks
* Replacing the throttle position sensor as needed
* Keeping the fuel injection system clean
Conclusion
Engine revving can be a frustrating problem, but it is usually easy to diagnose and repair. By following the steps in this article, you can get your car running smoothly again in no time.
