So as some of you know, my foots fractured, and apparently for 3 years lol. My roommate takes my subie out some times to get the fluids going. Well i happened to be sitting with him and we were on the freeway and he went to pass a car, and boost spiked to 15 PSI. My MBC is all the way in ("lowest boost setting") and i have noticed my boost kept spiking during WOT. Any one got ideas? the MBC has been there since i owned the car. Turbos are not my strong suit lol.

 

factory leggy turbo? does it spike then surge down and up or just spike and stay at 15?

 

Yea factory 92 SS, but the times i saw it spike it stayed there till he let off, it was only maybe a second or two if that.... but its worry some because I HAVE NO INTERCOOLER lol....

 

So i noticed my Boost solenoid had a naked nippled with a hose that went to nothing, so i capped it and still having spike :/ should i order another MBC like the GS one?

 

Do you have a two or three port solenoid? Post pics.

2 port: hose to intake and hose to t (turbo compressor and wastegate actuator)

3 port: hose to intake, hose to compressor, and hose to wastegate actuator

 

or take apart the MBC and see if the spring is rusted to all hell

 

I have a 3 port solenoid. Now i believe the nipple i capped went to the intake then. But with having a custom intake, i have no hookup for the hose :/

 

It's more like the turbo inlet hose area. Then again I dunno what your cars engine bay looks like. Just going off my car

 

I shall snap a pix today and show you all what i got going on lol..... EJ22T no intercooler! Say it isn't so! lol

 

if you haven't already make sure your wastegate isn't rusted shut either.

 

Wastegate moves freely.....

 

If your wastegate/flapper is completely shut, your car will continue to build boost until fuel-cut and bad juju follows.

Check the following:

1. Restrictor pill and boost lines for cracks

2. Which way did you turn your MBC? Not sure which brand MBC you have but majority is right (tightening/closing) raises your boost. Turn the other way and see if it changes.

3. Test your wastegate: connect a hose from compressor directly to wastegate and you should see somewhere around 4-6psi of boost. I believe your car boosts 8.7psi from factory and have fuel-cut is at 13psi. If your wastegate is working properly, your boost solenoid might be crapping out. I'll see if I can find my stock one for you to test. For now, you can adjust your wastegate actuator arm. 1/2 turn increments (make the arm longer) to lower boost. Make sure you take notes on how many turns you make so you can set it back once you fix your solenoid.