Here it goes im having a problem, my evo wont give more than 5psi at WOT! The exhaust note gets funny at higher rpms like there is a restriction in the exhaust.
The turbo builds boost till it gets to 5psi and there it stops for the rest of the power band.
I want help finding a solution for this, i had done some testing here and there.

1. Checked for vacc leaks (none found)
2. Tightend all clamps on the intake side.
3. Re-installed IC piping again.
4. Tightend bolts on downpipe & O2 housing.

The exhaust shop says my downpipe gasket is leaking, could that be the issue? Im not convinced that an after turbo leak would not help building boost.

I think the last problem is that my wastegate is stuck open but i still didnt make sure, i need help with that on how to check it up! Can i figure it out from the arm coming out of the actuator ?

Plz your thoughts on this.

 

When I had this problem it turned out to be a leaking waste gate flapper. I replaced the hot side and all was fine.

You're correct in the downpipe gasket not being the cause of your troubles.

 

Why does it say, "untuned 17 PSI" down at the bottom of your modlist? Were you running 17# peak boost, but now, suddenly boost has dropped all the way down to 5 PSI?

Is your car actually untuned? You are running around on the original factory tune?

Is the 5 PSI with the MBC tightened all the way in? So the MBC adjustment knob has no effect on boost level whatsoever across its complete range of adjustability. That is, presently you get 5# with the knob rotated all the way in clockwise and you get the same 5# with the knob rotated all the way out counterclockwise?

 

Well thats some old info i didnt change.
The car is tuned at 20psi now.

Yes all of a sudden my car lost all that boost! I get that damn 5psi rotated all the way clockwise and counterclockwise! I even removed the MBC and its still giving the same!

Im checking the exhaust manifold and hotside today.

 

Found a small leak from the gasket between the o2 housing and the hotside but this is not my issue i guess!

I need help figuering out where does the actuator arm pushed to? Mine is pushed to the passenger side, i think that means the wastegate is open?

 

Bump! Any help on that actuater arm position?

 

that means your flapper is all the way open

actuator arm should be pulling the flapper arm to the drivers side
when the boost overcomes its spring pressure the arm pushes the flapper to the passenger side and opens the wastegate