How many nos of O2 sensor in 93 NSX?

[jt6117]

Hi guys,
I am wondering how many o2 sensors are there in 93 NSX as i was told it suppose to have 2 upstream o2 sensors only but i found out it was actually 4 nos and the 2 downstream sensor connectors are mounted in the boot. Is it original or been modified? Clueless...

Thanks
Jay

 

[Honcho]

A US-market 1993 NSX is OBD-I and should have two O2 sensors. One in the front exhaust manifold and one in the rear manifold. If your car has four sensors (two in the manifolds and two in the cats), then someone put OBD-II cats from a newer NSX on your car. Assuming you do not have an OBD-II engine swap as well, the two sensors in the cats are not functional and should be removed.

 

[NSX-Files]

It could be that the 2 downstream O2s were wideband sensors that someone installed after or into test pipes but then abandoned them.

 

[jt6117]

The cable are different from all the o2 sensors and 1 of it has 2 pin connector and the other 1 has 3 pin connector. I was told it is EGT sensor but does 93' car need this sensor for ECU to function properly?

 

[NSX-Files]

No, the stock NSX ECU does not use or need exhaust gas temperature sensors.

 

[jt6117]

My ECU is Spoon ECU. Do you have any idea if spoon ECU need EGT sensor input?