When i brought my rx7 not 2 long ago the guy i brought if from said that it needed a o2 sensor cuz it runs really rich with out it. So i brought one and put it in but i cant find the other end that plugs into the engine i dont think it there but the guy said it is. Where would this plug on the engine be?

 

What year?

S4 is near the rear of the motor on the passenger side .

 

same thing on the 3rd gen.

look for a black plug hanging around back there.

 

S4's is like a greenish plug. Single wire connection.

 

Profile lists an '87 TII, so I'd assume S4 is the right guess. As mentioned, it's a green plug with a single black wire. It comes off the harness near the primary injectors, and loops behind the intake manifold on the passenger side.

 

acually i went and looked its a brownish plug.. i got my uim off

 

Yeah, sometimes they're brown/tan. I've seen that on some engines too.

 

man i been lookin all over i really cant find this **** i gotta find a pic of where it would be cuz i dont even think its there

 

all i can offer is this: http://www.rx7city.com/89-91manual.htm maybe you can get the 86-88 manual at the same place? im not even sure if they are different?

 

if u had to unplug the one u took out, how can u not find it now?

 

^ It sounds like the previous owner sold the car without an 02 sensor installed.

It's likely someone broke/cut the plug off, or it's hidden under the UIM now. If all else fails, you can run a new wire directly from the ECU, through the firewall & to the 02 sensor.

 

well i think if i unpluged it i would know where its at thanks,, but i found out that he cut it so i ran it to the ecu