1996 Nsx de cat pipes no O2 sensors

[snow patrol]

Hi everyone, i have a 1996 NA1 NSX with three bolt cat flanges, I have aquired some de cat pipes with no O2 sensor provision, can anyone confirm are the O2 sensors on the cats or manifolds?

Thanks

[AR]

If it is OBDII then it will have the sensors on the cats too.

Best way, get underneath and have a look at the cats!

Cheers,

AR

[Hagasan]

Hi everyone, i have a 1996 NA1 NSX with three bolt cat flanges, I have aquired some de cat pipes with no O2 sensor provision, can anyone confirm are the O2 sensors on the cats or manifolds?

Thanks

Three bolt flange cats shouldn't have the post-cat O2 sensors just the pre-cat sensors located in the manifolds. That's what my 96 car had anyway....

[AR]

Not always the case, as my 1994 NSX-R had them and some Japanese imports do too. Easiest way is a peekaboo.

[Hagasan]

Not always the case, as my 1994 NSX-R had them and some Japanese imports do too. Easiest way is a peekaboo.

OK fair enough, I was referring (in my mind at least) to UK models which should hold true to what I said...

[Kaz-kzukNA1]

Hi, snow patrol and all.

The secondary oxygen sensors (at the Cat) were introduced at the different timing depending on the world region.

For Acura, it was from 95-96 models. For Europe, it was from 97 model. For Japan, it was only applied from Sep/99 model.
Snow patrol, I don't know the specific region code of your NSX but I hope following diagrams will help you...

When you look at the Cat, be careful not to confuse yourself with oxygen and other sensors.
Especially on JDM, regardless of 2 holes or 3 holes Cat, there was a Temperature sensor inserted into each Cat up until Aug/99. Because it is JDM specific, it looks as if it is an oxygen sensor. So, just to clarify, there were no secondary oxygen sensors on ’94 Type-R or any JDM NSX prior to Sep/99.

Followings are the diagram of 2 holes/3 holes cat on JDM model prior to Sep/99.
5557 5558
On both diagram, #16 & 17 are the temperature sensors inserted to the Cats.
These were required by the Japan local regulation but then the regulation was changed and thus, no longer required.

On UK model, there were no such temperature sensors from the beginning.
UK 96 model on the left and 97 model on the right. On 97 model, #21 & 22 are the secondary oxygen sensors.
5559 5560

Regards,
Kaz

[AR]

Many thanks Kaz, that clears that one out!!!

[duncan]

Interesting and very helpful, thanks Kaz.
A further question, if for UK cars the secondary O2 sensors came in 1997 i.e the 3.2l engine. Were all the UK cars up to then, including the fly by wire [FBW] / 16"&17" wheeled cars [1995-1996], OBD1?
I ask because 1995 is given as the change over date, OBD1 to OBD2, for US cars.
My own, a UK 1995 FBW car appears to conform to OBD1.
Thanks