End all question to Sensors & Cats!!!!

[tholyoak]

If you are talking about north american cars, the early cars have 2 cats and 4 O2 sensors,with the cats in the midpipes. The later cars put the primary cats in the headers and a second set of cats where the primaries used to be. These still have 4 sensors, up and downstream of the primary cat. There are no O2 sensors after the second set of cats in the midpipe of the later cars. That is why you can eliminate the cats in the midpipes of these cars without CEL issues as the levels are not measured after the secondary cats.

todd

[porsche986spyder]

Originally Posted by tholyoak

There are no O2 sensors after the second set of cats in the midpipe of the later cars.

todd

That makes sense, but please be specific about the year model(later cars) you are referring to. I have an 01. Are you referring to 02-04??? If you look at the diagram of the 01 Boxster I have posted you can see there are sensors there. I even circled them in red.

[porsche986spyder]

If you look at this set of downpipes with cat deletes you can see they left the bung holes for the sensors close to the top where you would bolt them up to the headers. But there are no holes for the ones the were deleted from the cats themselves. What do you do with the wiring after you remove the cats and install the by-pasd pipes? You would still be left with the wiring hanging.