vaj

iTrader: (7)

Whelp, As the owner of a 04 STi with about 12k trouble free, cel free miles I decided to replace my perrin catless downpipe and stock STi exhaust with the Vishnu System (turboback). Installed it over the weekend and went for a drive. About 20 miles in I get a CEL. So I pulled over for a bit and did an ECU reset.

Drove another 20miles and got a cel $#!+ . Cruised slowly back home to write this up.

I'm wondering why the Vishnu pipe has the O2 sensor located behind the cat. Is this the O2 sensor the ecu looks at for A/F ratio? What is it seeing and how is it adjusting for it, I wonder...... I've pored over the EM forum and others searching for information on this one. Nothing I have found deals with this problem.

I'm going to my shop to have the CEl read and we may rebung the O2 sensor in the "stock " location just ahead of the cat.

I would love to hear some educated opinions on this one from all the wonderful engine tech-type folks here on this forum. My original post is on the Vishnu sponsored forum here at i-club but it seems quiet over there.

Thanks a ton (or is that a tonne)
vaj