Decat

[Cuthbert]

I'm having my decat pipe fitted tomorrow so i've unwrapped the pipes only to find there's no flange to fit the o2 sensor !!??
I take it as word that this is essential and needs to be fitted.
Any ideas anyone?
http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/sad.gif

[Martin F]

No it doesn't need to be re-fitted. This is a second O2 sensor and whilst ideally it should be re-fitted it won't affect the running of the car without it. My car just had this secondary one tied up out of the way and no problems at all.

[Cuthbert]

Yes, that was the answer I was hoping for. You're a gem of knowledge Martin. I was getting a slightly worried for a moment.
Just out of curiosity, why are there 2 sensors?

[Martin F]

AFAIK its to check the efficiency of the CAT. If they both read the same i think it can trip a fault code, but i stand to be corrected on that one. I think Nathan may know for sure.

[Cuthbert]

CAT? What CAT?
http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/laugh.gif

[Nathan]

Quote[/b] (Martin F @ Oct. 19 2004,19:56)]I think Nathan may know for sure.
We ALWAYS put the 2nd sensor back in on UK cars. This is somewhat of a pain as you know most frontpipes won't come with a boss which is why we go to the rather lengthy procedure of cutting out the mounting flange on the original frontpipe and welding it into the HKS one. It's grief but as far as we are concerned it's 'The Right Way' and we've never had a fault code come up because of it. Cat overheat sensors can be tied up though.

Can't be any more specific on what happens if the 02 is not fitted as the lads brains' are about to go pop working with the dyno at the mo so I'm keeping my distance... http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/biggrin.gif

[Chris Wilson]

Quote[/b] (Cuthbert @ Oct. 19 2004,17:22)]I'm having my decat pipe fitted tomorrow so i've unwrapped the pipes only to find there's no flange to fit the o2 sensor !!??
I take it as word that this is essential and needs to be fitted.
Any ideas anyone?
http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/sad.gif
I have a specific UK second cat replacement pipe I sell, with the second flange installed. I have had issues not fiting the second O2 sensor to UK models.

[Martin F]

Quote[/b] (Chris Wilson @ Oct. 20 2004,15:29)]I have had issues not fiting the second O2 sensor to UK models.
Can you elaborate on what those issues were Chris as you're the first person i've heard say they've witnessed a problem with not re-using the second O2 sensor.

[Chris Wilson]

Unstable closed loop mixture with excess fuel consumption on 2 cars. A third was unable to pass a BETS test (Basic Emissions Test).

[Cuthbert]

I've spent quite a bit recently & have a few things on order (wifey yet to find out) & so can't really afford to buy another pipe 'just in case' so i think i'll wait and see if any problems occur, then decide what to do. the B.E.T.s shouldn't be a problem as the cats will be going back in for the m.o.t.