front O2 Sensor location?

[Paul Whyte]

Hi folks,

I can only find one sensor each side of the exhaust system, in the location by the yellow arrow, I have a 99 boxster 2.5.

Can someone please post a photo of the standard exhaust system on a 986. As I am pretty sure mine only has two O2 sensors on it.

Also, when facing the rear of the car, the sensor location is infront of the cat. (upstream - towards the engine) these are ther ones I have replaced.

My car has still failed on emissions, I ran a diagnostics check on the car, and the readout states voltage going to the sensor, is the readout on OBD2 showing the readout from the cat, or from the ECU? basically, how do I check to see if they are working,

If anyone can help me with any recommendations for emission failures I would be most grateful. the garage said I may have a hole in the exhaust, I saw what looks like a small hole in the large back box where the two exhaust pipes enter either side.... would this effect at all?

thanks,
Paul.

[Frodo]

As I have stated many times in the past, I'm no expert here. (Long-time forum members will attest to this fact! )

Having said that, however, I did take a look at the description for O2 sensors at both pelicanparts.com and in my Bentley Service Manual (MY 1997-2004). They seem to clearly indicate the presence of 4 sensors on all models, 2 pre-cat and 2 post-cat. Have you looked closely at the Pelican Parts picture above, and closely at the exhaust arrangement on your car?