Originally Posted by IA Performance
Here is another option, it is free and avoids the hassle of the hoses coming off in the future. This is how the JDM ver7/8 STi cars are setup. We have lots of customer cars running this configuration without any CELs or negative side affects.
Two times in the 67K miles I put on my STi I had very strange AFR (super rich) at idle and easy driving.. the first time I messed with the purge valve and got it working (the valve seemed to want to be in exactly vertical position?).. well.. it happened again today after some intense tuning.... I performed the mod IA Performance suggested and the problems went away... I think the stupid valve was allowing boost to leak into the turbo inlet.
The only thing I noticed was that my purge valve bottom (from connector) port was connected to the evaporator tank .... the top port was connected to the intake... (backwards from the schematic IA Performance provided)
I made a few pulls after performing the mod.. my MAS voltage dropped (at given RPM/load) and it went slightly lean... I adjusted the intake calibration to address this and all is well....so far...
Thanks again IA Performance... for the super tip