Originally Posted by bobs
Sounds like you found the air injection system. It fires-up when you first start the car to force fresh air into the exhaust stream. The air mixes with the exhaust to do some kind of chemical magic that causes the catalytic converters to get up to operating temperature more quickly. To me it sounds a bit like a blow dryer.
Yes, that definitely sounds like what I mean. What a weird idea, I suppose it works, or does something beneficial, or it wouldn't be fitted. It does sound like a hair dryer though... I must say that is the strangest device I have ever had on a car and bizarre that it actually does what it is supposed to do. Still don't understand the benefit... weird!