The Importance of the Auxiliary Air Valve on the Exhaust
If you care about the performance of your car then you will need to know that even something as little as the auxiliary air valve on the exhaust system can rob you of those essential few extra horsepower that make the car perform smoothly. So it is very important to check that the valve is working properly. The auxiliary air valve helps with the burning of the exhaust gases, and if the valve is not working, that could spell a ministry of transport (MOT) failure. So you will need to know how to search for the valve and how to quickly fix it in case it fails to perform as desired.
The Point of an Air Exhaust Valve
On cars without a catalytic converter the air valve is placed very close the exhaust manifold and its purpose is to help burn any fuel vapors that may have escaped. That is because not all fuel is burned in the cylinder and tiny particles still escape in the exhaust. But those gases are still very hot, and if more air is pumped in the system, the extra oxygen gets them to burn up. In cars with catalytic converters, the burning of fuel is almost complete so there is a double valve system. When you first start the engine, air is still being pumped before the gases reach the catalytic converter so that any remaining fuel will ignite and will help bring the catalytic converter to temperature. After the converter reaches temperature, air begins being pumped in the catalytic converter itself to help in the catalytic process.
The Position of the Air Valve
On older cars you can find the auxiliary air valve on the exhaust manifold or even right on the cylinder heads exhaust ports. On modern cars equipped with catalytic converters, there will be a valve right before the catalytic converter and right after it. The valve itself is relatively inconspicuous but the hose bringing air into the exhaust system should be easy to detect and you can just follow it to find the air valve.
Knowing When the Valve is Stuck
It can be very difficult to know if the valve is stuck or not working properly because, even though it does help with the exhaust process, its impact is relatively low. To complicate matters, there are literally dozens of other conditions that could get the engine to lose power that are much more common than a failing exhaust air valve. If you find that your car is losing power you should get it to a specialized shop. They can simply check for the amounts of fuel in the exhaust gases and learn from that procedure if the air valve is broken.
Repairing the Auxiliary Air Valve
Obviously the simplest way to repair an air valve is to get the car to a specialized shop and have them check it and change it if necessary. However, if you would like to try to repair it yourself, all you have to do is to follow the air hose coming down just in front of the catalytic converter and follow it to find the valve. Next you will need to take the valve out, clean it and spray it with rust remover like WD40. If that does not loosen it up then you will have to buy a new one and replace it. You can go to AutoZone, Auto World or another local auto specialty store to find the parts you need.
The problem with the auxiliary air valve on the exhaust system is that it can be very difficult to know if it is broken without specialized equipment. But in order to have access to that system you will have to visit a mechanic shop and, once you are there, and they have confirm what the problem is, there really is no point in driving back home just to fix everything yourself. However the air valve has an important role in the way your car is burning its fuel gases, and it is crucial that you get it fixed. So, whether you decide to fix it on your own or have a specialized shop fix it for you, you should definitely fix the auxiliary air valve on your car as soon as you realize it is broken.