You will need
- a set of tools, clamps, new gaskets, manual.
Should immediately say that in a cold engine immediately after switching on for some time at elevated idle. This is necessary in order to have it warmed. That is, it is not difficult to guess that in the winter time of year the engine after switching on will take longer to run at higher idling speed than in summer. A normal level of speed for most cars is about 1000 rpm. The exact level recommended for your car, you will be able to find in the manual. If the revs idling your car does not fall after the engine is warmed up or "float", you need to look for the fault.
First we need to know what type of engine installed in your car fuel - injected or carbureted. If you have a carbureted engine, you can easily to clean it. If the car has a considerable age, the carburetor should be removed and cleaned, as often clogged the carburetor is the cause of the high idle engine speed. If you have no experience tuning and washing of carb, it is better to ask knowledgeable people who can quickly and quality to repair it.
Carefully inspect all rubber seals and hoses. A torn gasket can also cause high idle, as the system will flow more air than it should be. Pay special attention to flanges and gaskets, leading to the intake manifold. Try gently through the rubber hoses, parallel to follow the momentum. If you press on any hose they will fall, it means that you found the cause of the problem. Note on all connections. Worn clamps should be replaced, as they loosely attach the hoses and let the air leak out.
If your car is set injection engine, a mechanical way to change the rpm level is almost impossible. The fact that the speed depend on the firmware, which "poured" into your car. That is, the level control is programmatically. You can set the onboard computer to monitor the level of turnover in the online mode. If you want to downgrade, you should contact the specialists, who will be inundated by new firmware. But you should consider that too low idle speed may lead to premature wear of the generator.
Advice 2 : What is the idle speed
Idle speed is called a mode of operation of any device without load. This means that the generated energy is not transmitted from the source to the consumer. The term is used not only for the performance characteristics of internal combustion engines but also in other fields of knowledge such as electronics and programming.
In relation to the vehicle's idle speed, or idle speed will be referred to as running the engine with the clutch depressed or in neutral, when engine torque is not transmitted through the transmission to the propeller shaft, and from it, respectively, to the drive wheels. In both cases, the engine and wheels are disconnected.
Normally, the number of revolutions of idling in a stationary vehicle is stable and is 800-1000 rpm. If it is less, the engine will stall when the clutch is released, the increased rpm will result in excessive fuel consumption and accelerated wear of vehicle components.
Idle speed is regulated by several components and assemblies of the vehicle. First of all, the fuel supply system, consisting of an injector in modern cars or carburetor on older which are the units for mixing fuel with air, fuel pump, electronic or mechanical sensors, fuel pressure regulator and other components not directly influencing the number of revolutions of the crankshaft.
In addition, the number of turns is affected by the degree of opening of the throttle which regulates the flow of air into the engine, and valve operation at idle, which supplies air to bypass the throttle. In addition, to increase the revs, including idling, the accelerator pedal.
Unstable work of the engine idling can be caused by a number of factors. The first of these is contamination of components and assemblies fuel spent oils, soot, impurities in the gasoline and the air passing through the mesh filters these nodes, often in gas-liquid mixture is also water, which, as is known, internal combustion engines don't work. Also, the problem may be caused by problems with the ignition system, especially the angle bad (oxidized, loosely tightened), the contacts of high-voltage wires and other factors.