So I recently got my 02 S4 back from the shop 450 miles away from my house after losing the timing belt and blowing the engine on a road trip in california. The car was just about to break 100k miles during the trip and I had only owned it for about 4 months. I had to replace the entire engine and I told them to replace the turbos while they were at it since they are nearing the end of their life I imagined. So about 10k in repairs and parts later I finally get my car back and make the long drive home. Aside from a power steering fluid leak which I didnt notice until I got home and ill have to get fixed soon, the boost gauge seems to flutter when I get over 10psi. At about 10psi it seems to flutter back and forth about 1psi worth but when I get it up to 15psi or so (its chipped) it flutters about 4psi worth. I called the dealer and he told me that the new turbos would need some time to break in (a few thousand miles) and balance out that might be why its happening. This didnt happen on my old turbos and the only other thing that has change is that the vacuum line to the boost gauge got spliced and reconnected with a plastic coupling. The new turbos have about 6-700 miles on them now. Does anyone else have experience with new turbos? Does this happen? Any ideas as to what might be causing this? Is the dealer full of it? Do I have anything to worry about?

 

welll... how fast is the vibration back and forth. It could be that they didnt inlude a t-fitting wiht a brass reducer inside. if its just a normal t-fitting then your boost gauge will flutter rapidly back and forth.

 

Well I didnt look at the fitting itself, but I originally installed the boost gauge with the brass t-fitting and Im pretty sure they just used what I had originally when they swapped the engine. The flutter is VERY fast, fast enough that I can actually hear it through the gauge cause its moving so fast and its just kind of a blur.

 

You really should not be getting into full boost with such new turbo's.

The really only to see if there is anything wrong would be to have you VAG the car, and
get some logs from 03, and 115 to see what the actual & requested boost is.

If you are chipped it should be holding at 15psi, and spiking over that. What chip do you have?

 

agreed wtih sk s4.. but none the less... either there is a leak in that line or its a different t-fitting with no reducer... thats my best guess.. cause that is exactly what the reducer elinminates...

 

I've got the GIAC chip. I supped they could have possibly put the reducer back on wrong but these guys specialize in customizing audis and they are supposed to be one of the best Audi shops in the US working primarily on s4's so I would hope they know what they are doing, but i guess thats never really stopped anyone from being stupid before.

Edit: After taking a look at my engine I realized that they replaced the T-fitting with a different fitting so I called them and they are going to look for it. Once I get that hopefully the problem will be fixed.