I have a 1999 A4 that I just got recently. I do most of my driving around the city with very minimal highway miles. But I do drive the car very smoothly and havent really pushed it yet. So far I have only been gettin aprox. 15 miles to the gallon and I am filling it with premium gas. Is that normal fuel economy for the A4 or is there something wrong with it that I need to clean or fix? Also this is a very stupid question im guessing, at what RPM does the turbo kick in, and more gas is used when the turbo is in use correct? Also is it necesary to fill up with premium? Any answers would be appreciated.

 

Spark plugs, air filter and tire pressures should be checked.

 

The turbo kicks in at a very low rpm b/c its so small, but it also depends on throttle position. 15 MPG it pretty low, you might also want to check your pre-cat o2 sensor and check for any codes. I personally get around 25-26 MPG in the summer with all of the mods below. I also drive my car pretty hard when accelerating, but I try to be as efficient as possible when I'm just driving with traffic.

 

96audia4: How do you "check" an o2 sensor?

 

Thanks for the quick replies. As for the air filter, I did a search but there were various different responces. The current air filter is a K and N, should I recharge that one, or get a new regular air filter, seeing as many people said the oil from the K n N caused the MAF to malfunction.

 

1. Check the car for codes.

2. If you have access to a vagcom you can check the precat oxygen sensor. You don't state how old your car is, but the oxygen sensor is probably on its way out.

3. Spark plugs, if you are over 30K miles since the last change.

4. Run 2 bottles of high quality fuel injector cleaner through your gas tank (eg Redline or Techron).

K and N is a reusable filter. The MAF fouling is usually caused by using too much oil

 

i heard it kicks in around 3000 rpm (dont know if its true)..but the way i see it the car uses less or the same amount of gas when the turbo kicks in because the engine works the same amount...but the turbo gets its power from the exhaust and intake so it is getting you more power but using the same amount of gas..if that makes sense...

 

i dont have a 1.8T rather a 2.8, but was faced with the same problem. You should check these things in this oder:
1. Air Filter (if its K&N there is a kit you can clean filter and reuse it)
2. spark plugs, cables
3. MAF Sensor
4. o2 sensor

Hopefully you find the problem. good luck
d3

 

log its output with a vag-com

 

Mine starts to kick in before 2000 rpms (with testpipe).

When the turbo forces extra air into the engine, the car compensates this by adding extra fuel, thus increasing fuel consumption.