i have a MY93 WRX and can only get about 6psi of boost. I reset the ecu using the connectors under the dash and after that i get 11ish psi for a few miles then it goes back to 6psi. If i then do another reset i'm back to 11ish psi of boost. It doesn't display any error codes.
what could be causing it? Car is standard apart for downpipe and all the cats are off.

 

bttt

 

I would say your car is detting and ECU goes into "limp home mode", limiting boost to just 0,4/0,5bar. Have you hit fuel cut in the past? Do you have knocklink installed? Are you using octane booster?

There could also be your fuel pump failing, car could det also because of quicker spool up due to exhaust changes (better flow= leaner mixture=det) and many other reasons...

Kristijan

 

Check for loose / split hoses to / from turbo, boost control solenoid etc.

 

would det not cause me to get error codes?

i don't have a knock sensor apart from the one that's standard to the car, does that go faultly? I found one of the cables tapping it so tied it back so nothings touching it anymore but didn't stop me losing boost.

Never use Octane Booster but always use Optimax, do you think if i do another ecu reset and use Octane booster i wouldn't get det and i was having the problem with the standard downpipe.

No idea what fuel cut is so not sure if i've ever hit it. What does it look or sound like?

 

With det you don't get error codes just timing correction which you can see with Delta Dash. If timing correction isn't enough ECU goes into limp home mode and reduces boost.

Standard knock sensors are Ok but many people get konocklink just to be on the safe side (recommended). Added octane booster to the fuel for jap import (as it is WRX i assume) is a must. You can try adding booster then drive for a few miles and then reset ECU and see what happens.

When you hit a fuel cut it's like hitting a brick wall when on full throtlle.

Kristijan