Hey guys, I spent most of yesterday searching the web for a solution to this and I am out of options.
The car is a 02 WRX AP stage 2 with a catless DP. I bought the car used and added those mods myself. Everything was working fine until I took it to a HPDE. The car was running strong and then I started to notice that every session I went out the peak boost would be a little lower every time and now it's at the point were it will only reach 7 psi max, wastegate pressure. It's pulling good vaccum at idle. Accelerating feels strong as boost builds but then it just stops at 7 psi.
So here's what I've done so far. I've visually inspected the vacuum/boost lines and even replaced a few. The resistor pill is in the correct position and all lines are clamped/zip tied. I don't have access to an air compressor so I haven't done a boost leak test yet. I'm thinking this may not be a boost leak since it's pulling good vacuum and it stops right at 7 psi. I could be wrong though.
I tested the BCS as well. With the car in test mode, the BCS does not make any noise or cycle open and closed. I hooked it up to the battery and it does open and close with power applied to it. I also sprayed some brake cleaner in there to clean it out. I disconnected the line to the wastegate actuator and went for a careful drive and it still won't boost past 7 psi. So as far as I know this rules out a bad BCS.
Wastegate actuator arm? I haven't pulled the heat shield off yet, but this seems ok. Is it suppose to move if you just grab it and move it back and forth? It doesn't really move so I don't know if maybe it's stuck open. But then again, wouldn't this cause no boost?
I reset the ECU in case the car was in a limp mode or something. No luck.
Could a bad exhaust leak cause this?
Any ideas? Thanks