Ok, but are they BOTH in the header? Or is one in the header and the other is in the cat?

I know the LX has the cat built right into the header, that's why DC doesn't make a header for the LX... :dunno:

 

One should be before the cat (or straight pipe) and the other behind. The computer needs to see the temp differance after the cat or else "Check Engine"

Its actually better to have it up close for a bit more accurate readings but since they are headers your better off having it near where the 2 - 1 come together. The diameter of each runner (pipe) is so small it would actually be in the way, clog, restrict flow.. On cast irons this isnt a problem as they come together within 6 inches of the head. I had to hook up a lambder meter when I was fine tuning an Apexi AFC to get real ontime accurate readings on headers.. Then I plugged it back up.. But an O2 there is simply to tight to fit for you. .. Just lengthen the wires to suit the distance.. It will not fault the way your engine runs.

O2 sensors run around a ripoff price of 220.00 for Bosch so you might want to be careful you dont bust it..

I got a turbo now and its bitchen for a stable o2 reading now All because the o2 is now busted due to an idiot not being patient!

 

the 96-00 dx civics has only 1 O2 sensor on the header itself you would have to extend the wiring to accomodate the bung in the back. the second O2 sensor is for the cat, on the stock header there is 2 O2 sensors one before the cat and one on the cat.

hope that helps.

 

oh one last thing.. If you ever want to have a Hondata program to your car.. You'll only need one o2 sensor (in front of the cat) and disconnect the one in the back.. The hondata replaces your ODBII ECu which uses 2 O2's with an ODBI and your shit will haul ass! Way better than installing an APexi V-AFC.. Also AEM has a ECU out as well but costs more.. So if your thinking of doing that.. dont waste your time with the O2s just get the computer now.

 

Hey guys, thanks for all the input. I'm still a little lost, but I'll read things over again and ask my friends. Yeah, my car is really weird... it's 96 Civic EX, but I haven't seen any other EX's with 2 O2 sensors where mine are... I've been thinking it was swapped before I bought it used? (at the time I was clueless about cars). The sensors on the stock header are on the top of the manifold and one vertically under that where the pipe bends 90 degrees. I can't remember if there was one before, after, or in the cat... maybe in the cat? I don't know because I'm up at a university right now and I left my car behind at home, haven't fiddled with it in a while. Hopefully that'll help someone out figure out this problem?

 

hondata= $170+
AEM= $1100 +

he didn't tell you that

 

hondata 170+ Wow
s200 hondata kit with boost / full throttle shift otption.:
it costs 150 for the computer, 100.00 for the harness conversion kit from ODBII to ODBI, then a basket, Eprom another 150.00+.
alone..

Mechanic to tune (not many out there with hondata experience)
for instance http://www.rpmnyc.com/ . charge you a 3-4 hundred to install and program at the same time run it on the dyno for 2 hours. Total average cost 900.00

AEM : 1,300 without including programming and installation! lol

My hondata shit just got finished last week from Performance racing in Methuen MA.. My car was just Dyno'ed at 302 at the crank! stock pistons and rods!.. Full throttle shift goes in tomorrow. It makes the rpms drop a bit when i pull the clutch while leaving my right foot to the floor. then when the clutch is back out for the next gear ALL that boost is ready to snap my neck.

 

didn't know all that, thanks