I have got a fully de-cat exhaust system on m MY95 WRX but was unable to remove the lambda sensor from the origanal downpipe.

What I need to know is wheather or not I need to put another sensor in the new downpipe or is it ok as is?

The reason being that I have been offered one for a good price but don't want to spend the cash if I don't really need it!

Thanks in advance, Martin

 

I won't run very well on cruise. As you may or may not know the ECU runs in effectively one of two modes, open loop or closed loop.

Closed loop is used when cruising around off boost, the fueling is set to give a lambda of 1 so that your car will pass an MoT, meet emissions regulations etc. The ECU uses signals from the lambda probe, MAF, and MAP sensors along with RPM , engine load etc. etc. to do this.

Open loop is used when on boost. The lambda probe isn't used as they tend to under read when they get hot anyway. The ECU determines fuelling based on MAF and MAP sensor readings, along with all the other stuff, and aims for a nice rich mixture to prevent det. This is obviously not emissions friendly and if read the lambda value would be much lower than 1 indicating a rich mixture and high CO content in the exhaust gases.

 

I think you do need to fit one if you are in any doubt after reading the above.
With the right ring spanner it will come free out of the old down-pipe.

Take it to a garage and it will cost you 'a pint' I think.

Besides, if you leave it out you will need a threaded plug to blank off the hole, cost is about 3 pints (literally)

Graham.

 

Thanks for your input guys, I think I will take up the offer. I guess ,after all, Subaru put one in for a reason.

 

Shall I need to do an ecu reset when I fit it or will it be ok?