Hi, I recently bought a 99 civic lx with i/h/e and noticed it was running pretty fat when I saw black residue around the exhaust on my back bumper. Also, friends driving behind me say my car smells like sh*t so maybe that is another effect of this. So I went to look for the O2 sensors (I believe there are supposed to be two) and only find one! It is down just past the header on the exhaust and looking on the header where there is supposed to be one there is just a bolt in its place. Normal? I didn't think so. I know I can buy one for around 60 bucks, but I was looking where the existing sensor hooks up and there is no where for another one! It appears the wires are spliced on so I think something is a little bit fishy. If you need I can post a pic. Could the O2 sensor be causing the engine to run crappy (it has) and how do I go about hooking it up? Many thanks!!!

 

bump good question

 

LOL...

D16Y7s have 2 02 sensors. Not having the primary one will cause the engine to run rich, run like **** and should set off a CEL.

Good luck with the wiring, sounds like someone hacked it.

 

Okay that definitely seems the case, the CEL light is on and it's running rich. My main question now is how can I figure out where to hook up the main O2 sensor. Is there a wiring diagram or anything because I can't find any and I am not very familiar with how it works. Thanks

 

Sorry, I don't know. If NOFX wasn't banned by somebody she could have probably helped.

TTT

 

Both Sensors are right in the front of the engine.. one before the cat and one after the cat. You might be missing the one on the top of the header. Save yourself some time and buy two from a autoparts store and have a garage do it... only cost me 50 bucks to have a garage put them in. If you need to do it. Go to a parts store online and look up cats on your car... pictures usually show two holes. Thos are both 02 sensors. The wires are really short.

 

Location of the sensors is not in question, it's the wiring. His harness was hacked and he needs a diagram - or something.

^TTT^

 

Would it help if I took a picture of my engine bay.. I have the same engine.