No Boost, No Power. Some Boost Initially Then Taper Down
 

when i floor it the gauge starts to go up then if i hold it it slowly goes down 1987 turbo i have no power like the turbo isent working

Assuming your exhaust is not clogged, you probably have a bad turbo.

Pull the TID and then try to turn the compressor wheel with your fingers, as well as push it back and forth. If it's hard to turn and you get a lot of side to side and front to back play, the turbo is hosed.

what about the blowoff valve?? because when i hit it it jumps up quick like up to the first little lines not trying to be a know it all just that somebody told me that.i had just put this used motor in and it was working from the get go and i only put on 50 miles and it semed to happen quick??

I don't know about a BOV taking out all your boost...it really sounds like a dead turbo, but do what AC said, and check for play.

turbo is froze up /why?? this is an s4 will s5 turbo fit i know that the housing is different is the turbo the same i have an s5 turbo

So the turbo doesn't move at all? That sucks...It's going to need to be rebuilt or replaced.

Because it's a used engine you have really know way of knowing how it was abused in the past. If it's J-spec, it could have been sitting for years.

Don't downgrade the S5 with an S4 turbo. If you do, you loose about 20HP and need to replace the manifold and oil feed line as well.

Unless I am too tired to read correctly, I think he wants to put S5 Turbo in an S4 car.

pulled the coil wires to see if it was getting oil it only does when pressing on the accelerator. put a diifent turbo on it and it seems to be fine