Just helped my kid buy his first car.

2012 Audi A4 quattro with the "premium plus" and "s line" packages. 115k on the odometer.

On the way home, noticed that it smokes white when cold, and even when warmed up it gives a little bit of white smoke when you accelerate from a stop light. It has a smell to it like it is running rich. Also notice a light squeal from the engine under hard acceleration- sounds like maybe a belt or an air leak.

It runs great, though. Lots of power, got a 34mpg average on the 140 mile trip home according to the dash.

Some other clues:

Its loud. At a steady speed, it's nice and quiet- but under acceleration, it sounds like a serious sports car exhaust. It isn't a problem in and of itself, but it's much louder under acceleration than I'd expect from a luxury car. Looking underneath, I dont see any holes or missing components to the exhaust.

Second- I found what looks to me like an O2 sensor zip tied to ha hose under the hood. Full sensor with the wiring and connector- not installed or connected to anything, just zip ties there.

It also has a cold air intake installed


No CEL.

I'm theorizing that a previous owner did a cat delete and gutted the cat and muffler, then removed the O2 sensor to stop the CEL.


Would that cause the smoke?

 

White smoke sounds like moister in the system. Possible with the O2 removal the car is running rich and at start up the exhaust system is still cold allowing more to "burn off" closer to the tail pipe. Just a guess an that.