can anyone tell me where exactly is the o2 sensor on an 87 carbureted civic,or if there is one? i checked the exhaust manifold and pipe but i don't see one anywhere.on my other car a mazda mx3,and every other car i've seen the o2 sensors are in plain sight somewhere on the manifold or exhaust pipe,and since i've never owned a car with a carb before i'm wondering is the sensor placed somewhere else or look different?

i don't think the carb has one and if it did i'm not sure what it would do...

On a carbureted HF it's directly on top of the exhaust manifold.

what does it do?

it just stands there doing nothing...the only thing its good for is for conecting an air fuel ratio gauge...other than that i dont know...think the manual said somthing about emitions.../

well i guess this isn't an hf,whatever that means lol.

It regulates the carb to reduce emissions.