I fitted a decat downpipe to my 96 wrx import and the original sensor broke. Problem is it was really weird looking, it was very skinny and had two wires one inside a wee tube and the other outside the tube..so as to seperate them...strange. Anyway all the replacement ones i have looked up look completely different to the original, there is only 2 wires on the connecting plug and all the ones online have 3 or 4 wires?? Can anyone help im at a loss with it...

 

Might the old one that broke be the cat on fire sensor?

 

See im not sure..it was positioned in the cat housing right at the bottom of it towards the back box?? There are no other holes for the sensor to go in? were are they normally placed on the downpipe??

 

Mine is the same, its in the downpipe but nearer the middle section rather than at the top by the turbo. I have after market downpipe had holes for both. Mine is a 1995 wrx import.

 

So what did u do then? Mine has holes for both aswel.

I just assumed that the sensor i took out of the cat was the lambda sensor, maybe it wasn't?? But then were was it meant to be because there was no other holes for it on the original subaru downpipe??

 

as above, likely to be the cat on fire sensor, have a look in the exhaust manifold for the o2 sensor

 

I put it back in and blanked off the top one with an old lamda sensor i had. But as p1drifter say there is one in the manifold.

 

Yea there is one in the exhaust manifold..does that mean i dont need one for the downpipe??

Lads im so confused here..

 

not sure if it will cause the engine check light to come on if it is not connected. It would be worth keeping/replacing if you ever decided to change the downpipe back for a standard one tho.

 

Iv had her started and no warning lights are on??

 

if no lights are on then perhaps it wont matter. just keep it in mind if it does then. But i suppose if its not reading the cat is on fire it wouldnt come on. So it would think everything is ok.

 

Id really like to know were the original lamda sensor is in these cars? Is it in the downpipe or the manifold or maybe both??

 

The early classics the lambda is in the headers then the later cars its in the downpipe. Not sure what year it changed though. Just look under the car on the left, you will see the lambda if its there

 

Per post above, the Lambda sensor on cars 93-96 was located in the collector of the headers before the uppipe. On cars 97 to 00 it is located just after the turbo in the downpipe and cars 01 forwards located in the collector before the downpipe close to the driver's side front wheel.
It is easy to relocate the Lambda sensor from the collector to the downpipe just by cutting back in to the wiring loom insulation to free adequate length to reach the downpipe.
The sensor you describe is the CAT on fire sensor which is not required and you can get an ECU fix or CEL fix to put out the warning light.

 

Would there be any benifit to moving it to the downpipe? On the 200sx its in the downpipe just after the turbo.

 

The only benefit moving it to the downpipe would be if you wanted to use the hole in the collector where the Lambda sensor is already located for an alternative purpose such as EGT but putting sensors pre turbo does have a risk if they break up.
It is no hassle to leave the existing Lambda in position in the collector, unplug it and put the new Lambda in the downpipe, assuming it is an aftermarket with a Lambda boss which most downpipes are (mine have two Lambda bosses, one for OE narrow band and a second for mapping with a wide band or for a permanent wide band guage.)
The advantage of putting it in the downpipe is it is much easier to get to.

 

I have Just bought a jdm decat down pipe for my UK 00MY classic , am i right in saying it wont work on my car ?, it only has this fire sensor and no other holes for the lambda.

I thought it would have had both holes but I guess not .

 

I suppose the 2 options you have is to sell the downpipe or get the earlier manifold. Not sure how much you would get charged to make the lambda hole in the downpipe you have

 

Thanks Shane mark gave me your number but i think you have answered my question now lol

 

Any aftermarket downpipe I have seen has a Lambda sensor hole. The ones we hand make have two, one for the narrow band sensor and a second one for mapping with the wide band or for a permanent wide band display on the dashboard.