Hi all,
I am after some info regarding the 2 oxygen sensors on the exhaust system on my 1994 wrx.I require a new oxygen sensor on my car,but the question is which one.My wife stopped in at the ex subaru dealer which services my car,and apparently there are 2 sensors,one being in the downpipe area,and the other in the mid section.The exhaust is standard apart from a scoobysport backbox.
The problem with the car is that the emissions are too high at idle but o.k at higher revs(presumably running rich).
Any help appreciated.
Cheers
Dean

 

I had to replace the oxygen sensor on my wrx (MY95). It is located in the header as standard, not in the downpipe. The later cars have them in the downpipe. If it is in the downpipe then it has been moved. If you have a standard downpipe then the thingy with the braided wire on is a preheater for the cat, only the jap spec cars have these. You don't actually need this. I don't think there is any sensor in the mid section, there wasn't on mine when I changed it from the standard one anyway.

Hope this helps.

 

If the sensor is buggered, which the older cars usually are then the default setting is to run rich when the signal from the lambda sensor is suspect.

This will give you attrocious emissions.

get yourself a bosch LSM11 lambda sesnor and stick it in the downpipe and not the headers, it will last much longer.

As for this second sensor, I am not sure. The new cars run a wideband and a normal and use the difference in the frequency of oscillation at cruise to determine the efficiency of the cat and nox traps. This does not affect you, so dont worry about it.

 

Dean

It seems to me the dealer was talking about a later MY car than yours, in your case the sensor is in the header (also known as exhaust manifold), its not in the downpipe, and also your car won't have any type of sensor in the mid-section. Its best to move the sensor to the downpipe, although since yours is 94WRX OE there isn't a location for it. If you ever change your downpipe get a later MY one if OE or any decat dp, then you can move the sensor. At present you'll have to replace the faulty one in its existing location.

Justin

 

I also need to replace my Lambda sensor! I have a MY94 WRX & the sensor is in the manifold!

I also have the preheater in the downpipe, which is de-catted. SO I'm thinking if putting the lambda in the downpipe & the preheater in the manifold or just leaving the old lambda there in the manifold as I know it's going to be hard to get it out.

Does anyone have any recommendations?

Regards

Johny.

 

Thanks for all the replies,this will help alot.
Cheers
Dean