Jon Brokaw

I just bought this car a couple of weeks ago non- running for 300 bucks. I got it running great (loose ground behind the coolant tank) but I've run into a snag. I'm not very familiar with Audi or turbos in general. I know that there are a lot of topics on boost problems, but I have not been able to find an answer to my particular problem by searching the forums or google or any other forum.

Car runs great but shows no boost at all. As a matter of fact I'm actually pulling a vacuum all the time. At idle, I'm pulling 28 in/Hg and at WOT its pulling around 6 in/hg of vacuum. My MAF readings peak out at about 135 grams per sec. I've pressure tested, smoke tested, leak tested this thing from every direction. I've pulled the n75, same results. The only codes I'm pulling are:
17526 - O2 sensor Bank 1 sensor 2 Heater open circuit
17522 - O2 sensor bank 1 sensor 2 Internal resistance high
16815 - Warm up cat efficiency below threshold on bank 2 (already checked and this is a bad cat. sensor 1 and sensor 2 follow each other)

My first question is would any of these codes cause my to stay in vac?
My second question is if its not code related is there an easy way to get to the turbos to pull the inlet piping for inspection?

My biggest worry right now is that I have a blown turbo (or pair of turbos)

Jon Brokaw

Couple of vid clips for sound.

PaperToast

check all the rubber turbo hoses for cracks
they like to blow out

Jon Brokaw

Would the hoses have leaked with a boost leak test or a smoke test through the turbos and through the intake manifold?

Jon Brokaw

Ok, so today at work while it was slow I went through all the lines. Everything looks like its been replace recently. All new rubber, no rot or cracking, and everything was dry and clean.

Something I forgot in the original post, and this is a big thing to forget, is that the people I bought it from claim to have put a new motor in it in August. So far I'm not impressed with what I've seen. It makes me question if the hoses are routed properly.

The first thing I found (as stated in the first post) was a bad ground. I've since found the bank 1 knock sensor unhooked, the ABS wiring connector not seated properly, and the fuel pressure regulator not hooked up to manifold vac.

Jon Brokaw

I've pressure tested and smoke tested every line/hose on this car. No leak what so ever. Still no boost. Buddy of mine has an a6 the same year that runs flawlessly that he let me borrow to experiment with. I've swapped diverters, n75, the n249, and still no boost. I temporarily did an n249 delete and put a manual boost controller in place of the n75 to take the computer out of the equation. Still no boost. No smoke, no noises, no nothing. I'm still really hoping its not a blown turbo, but if it was only 1 turbo bad wouldn't I still see some kind of boost, only reduced? Or am I missing something completely at this point?

PaperToast

seeing how you've done a great effort of troubleshooting all the usual suspects, might be time to take it to a shop to get looked at
only other thing that i can think of is double check all the vac lines and make sure they are all connected/routed properly
given that you found some things missed from the 'engine swap' . . .

also feel free to head here and post http://forums.quattroworld.com/allroad/
tons of folks that know these motors inside out