02subieguy

I have a 2007 STI bone stock with 76k. It is unable to build boost. I've noticed that over the last month it wouldn't build full boost and would take a long time to reach peak boost. It's slowly tapered off over the last few weeks and now it won't go past 0.3 bar. I checked all of the vacuum hoses around the turbo and checked the intercooler lines. They all seem tight and clean. I didn't do a boost leak test but will do one during the week. It's weird that I am not able to even build boost off wastegate pressure. Either my turbo is shot or I have a huge leak which I don't think because I've checked everything (you never know though until you test). Will a bad boost control solenoid cause no boost? I did the test to hear it click when the key is on and I can't hear anything clicking. There is a sensor of some sort that is connected to the intake manifold that clicks and has two larger vacuum lines connected but from what I read that is not the BCS. I am stuck right now and am so frustrated, so if anyone can give me any ideas I would greatly appreciate any input. I've also searched up and down every WRX forum for similar symptoms and most threads are fail with no results or fixes.

Update - There are no check engine lights. The car idles perfect, no smoke coming from the tail on start or driving, no smoke coming from the oil filler cap.

Jimboi

iTrader: (2)

Up pipe gasket leak maybe?

02subieguy

Possibly, but it would have to be a serious leak to cause .3 max boost. I do hear a rattle which did not happen before when in gear slowing down. It's dark right now so I haven't had a chance to check it out. My car doesn't seem louder than normal and would be obvious from the sound I would think.

vietpunk916

iTrader: (7)

Happened to me at 30k on a stock 06 wrx. It was the stock downpipe that clogged up. The car would not go into boost at all and a check engine light came on. It drove like it was on limp mode. Is your downpipe stock?

02subieguy

Downpipe is stock and I have no check engine light. What could possibly clog the downpipe?

wrx4memp

iTrader: (3)

leaded fuel or additive, running rich for prolonged time, fowled pluggs, antilag the extreme ignition retard kind... basically unburnt or wrong fuel in exhaust...

bad news:

same thing here... mine wasn't clogged i melted mine... it was abuse driven 3 times a month for 2 years to LA and back and the goal was to get there as fast as possible... you fill in the blanks... catalitics have a max operating temp and constant abuse will start melting and killing it a little at a time... and it got so bad that that i barely made it uphill while it was on its last limb... and also killed the turbo along with it... the clog in exhaust was creating stress in turbo somehow and it gave out...

good news:

easy to test out... change downpipe and/or tuebo with someone on the forum... it if fixes it buy aftermarket and be happy... or take it to the dealer if it is truly stock as you say... there is a federal law that warranties catalitics and CO2 emission control up to 100,000miles the dealer will most likely try to deny it so be prepared to have something in writing it should be in the warranty manual if i remember.

02subieguy

Just incase anyone was wondering, my cats in the downpipe broke up and clogged the exhaust. Swapped it out and it runs good again.