I have a question regarding, i suppose, conflicting information. I want to change the Fuel Filter in my 2000 1.8 NA A4. My Haynes manual tells me to disconnect the battery and pull the fuse ( I think its #228, dont have book on me). I think this is to depressurise the fuel system, but may be to prevent sparks?

Anyway the book then warns that disconnecting the battery may cause drivability issues which I may need to bring the car to a dealership to solve. This sounds like madness, I read about you guys disconnecting the battery all the time.

Is it just a matter of reconnecting the battery, then switching the car to the on possition to allow the car to calibrate the throttle body before starting the car? Is this even necessary? Are Haynes just being super conservative?

 

leave it connected just dont have your keys in this is how you do it right =]

http://www.audiworld.com/tech/eng49.shtml

 

You dont need to, I just did mine yesterday without dissconecting the battery. It unplugs right out of the top of the basket. Pull the your fuel pump fuse out first and you will not have any power supply to your basket and pump

 

Any questions let me know and I will explain the process for you

 

To depressurize, you can just pull the fuse try and start your car till the fuel is gone. then open your gas cap and it will releive the tank

 

Yep.. all you need.

 

dont disconnect battery for too long if you do.... you might want to make sure you have your radio safe code!

 

Ok, so no need to disconnect for the filter change. How about in general?

If i disconnect it for 30 mins will it clear codes?
When i reconnect it will there be any side effects?

 

Yes even 10 min will clear codes. Once you reconnect do the throttle body thing then start the car. For the next 50ish miles your car will be in adaptation mode and will NOT pass emmissions. You may not see full power either while the car re-calabrates itself.

Josh

 

Just a tip, when I changed my fuel filter, I removed the fuel pump fuse, and ran the car until it starved of fuel. This gets rid of a lot of fuel still in the lines, so you won't have a gallon of fuel spilling all over the place when you take out the old fuel filter.