Hi, I have audi 1.8t A4 1995 quattro. I had boost problems and my car went to something like LIMP mode and made no boost(slow and couldn`t hear turbo at all).

So I bought boost gauge. I installed T piece just before engine intake, small line that goes between DV and engine. I notice that line is really hard(not elastic) and it cracked just before DV. I changed whole line. After I did reset by removing negative wire from battery, and it started boosting again.

Now, the problem is that I think it still doesn`t boost like it should. I have stock ecu. I tested all gears from 2000 rpm and this is what happens.

-In second gear pulls strong (linear) from 2000 rpm till 3000 rpm, then there`s flat/slower acceleration till 4000 rpm. Then strong again till red line.
Boost at around 2500rpm reaches 9psi, then at 3000 rpm drops to 6-7psi and holds 6-7psi till 4000 rpm, then pulls great again and holds 9-10psi till 5000 rpm and slowly fades till redline like it should.

It is the same with higher gears but less noticeable and the range where boost drops for ~2psi is smaller, in fifth gear only between 3000-3400 rpm boost is 7-8psi, and after that it holds 10psi like normal, and slowly fades after 5000 and something...

In first gear it is the most noticeable, and that flat/slower acceleration is from 3000-4500rpm almost, so it depends on load I guess...

I`m going to chip the car, so want to make sure everything is fine before raising the boost with chip.

So is this normal or should the boost after it reaches max(9-10psi) at about 2500, hold it till ~5000 rpm?
Just to mention, n75 is new, and DV is 710N 40k miles old. So what do symptoms suggest, leak, DV?

Thanks ahead.

 

Anyone? I`m not sure where to start, to find new DV or look for a leak or something third.

What are symptoms for bad DV, because my boost drops on the low engine load and always start at about 3000 rpm, and returns normal after ~4000(depending on gear)...