I owe an A4 2.8 1998, bought the car about 4 1/2 years ago, and It's a super great car, very little repairs. always, to my best, maintained it properly...My question is: since I bought it, no matter if It's -30 degre Celcius (since I live in Canada) or + 30 degre Celcius, every single time I start the car even It's more than 3 or 4 hours without use, the engine runs faster (around 1000 RPM) for about a minute then comes idle (under 700 RPM). It doesn't bother me at all but I was just wondering if the engines would run normally everytime the car starts? Was It made like that? It never affect performance or engine trouble but out of curiosity.....

 

mine does the same thing...
i just let it idle till the RPM's drop?

only when its cold though, i thought it was normal? but who knows?

 

On start-up, OBDII cars do a number of things to keep down emmisions. With Audi's, this includes starting the AIR pump (secondary air injection) which helps the cat work when cold. In the mean time, the ECM runs the vehicle in open-loop mode, which means the fuel is metered based upon a set map per certain observed conditions. Often, the car will run very rich to make up for poorly atomized cold fuel and to help the cat light off until the engine starts to warm up. Once it gets to a certain operating temperature (begins to warm up), the ECM will switch off the pump and begin to run the car in closed-loop.

All of this means: the engine will idle at about 1000 RPM until the ECM sees fit to drop idle down to normal range. If it's cold, it usually takes a few minutes longer. If the engine is warm enough or has recently been run to full operating temperature, this will not usually re-occur again on start-up.

 

Thanks a loy Guys, I appreciate all the details Tweaked...So there's nothing to worry about.
Awesome!

 

No problem. Dn't be afraid to ask questions, its how we all learn.

 

yea ask questions but before you do read the stickies and newbie guides, you can find a lot of useful information....