i have a civic dx manifold with the o2 hole in the top, and i have a dsm o2 housing on the turbo, which should i plug and which should i put my stock (primary?) sensor in? before or after the turbo? before the turbo the wires a streched kinda hard.

and the one by the cat - does this have to be pluged in ? i have a obd2 to obd 1 harness, did ob1 civics have the 2nd sensor even? this is on a d16y8

 

heres a pic of the same ----

 

I would use the one in the O2 housing for ease of use. Then I would plug the other 2. OBDI ecu's use only one. The plug size is like 18x1.25 if I remember correctly. Just go to Vatozone and go through the oul drain plugs in the back and match it up.

 

y ai got oil drain plugs from the store - they work perfect. so using the o2 housing one after the turbo is ok?

 

Yep.