Downstream O2 Sensor Q.

phenomeneon21 · Post by **phenomeneon21** » Thu Mar 15, 2007 4:24 am

I'm really getting tired of the CEL related to not having my downstream O2 sensor plugged in. The only problem is due to the the LTH, the cat is quite a ways down the exhaust tunnel. I tried taking my car to various places to see if they would extend my O2 sensor. None of them will touch it.

My question to you guys is can I do it my self with some basic wire? What gauge would you recommend (14,18, etc.)? I'm getting real crappy gas mileage, tired of seeing the CEL, and need to plug the hole in my cat with something...thanks...

00element10 · Post by **00element10** » Thu Mar 15, 2007 8:39 am

when we extended mine, we used wire from a spare honda engine harness and it worked fine. Just look for something of a similar gauge. I dont know what gauge the o2 sensor is to begin with otherwise i'd let you know.

turbodudey · Post by **turbodudey** » Thu Mar 15, 2007 12:55 pm

The power and ground wires going to the sensor are 18 gauge, and the signal wire is 20 gauge.

You could extend all of the wires with 18 gauge and it would just fine.

On a side note, the downstream 02 sensor doesn't have any effect on the gas milage you're getting. Its only purpose is to monitor the functionality of the cat. Not having it plugged in won't affect your fueling at all.

quicksilvr · Post by **quicksilvr** » Wed Mar 28, 2007 8:14 pm

turbodudey wrote: On a side note, the downstream 02 sensor doesn't have any effect on the gas milage you're getting. Its only purpose is to monitor the functionality of the cat. Not having it plugged in won't affect your fueling at all.

Agreed. I'm curious which code(s) you get that throws the CEL.

I get P 0140 (1/2 O2 Sensor Stays at Center, Neither rich or lean condition is detected from the oxygen sensor) all the time, and I just recently also got P 0172 (1/1 Fuel System Rich, A rich air/fuel mixture has been indicated by an abnormally lean correction factor). That said, I just took a 275 mile trip and averaged 31 mpg for that tank of gas. It included numorous WOT 6700 rpm stints as well.....

white2000neon · Post by **white2000neon** » Mon Apr 02, 2007 10:17 pm

I have a very similar setup as you and i did the sparkplug anti fouler mod and it works great been 4000 miles and no CEL. Search for it the is a how to or something floating around.

ragek23 · Post by **ragek23** » Mon Apr 02, 2007 11:08 pm

when you extend your 02 wire make sure the wire cannot touch the pipe at all even with the exhaust flexing because my wires melted, shorted and created lots of hell for me.

ewetho · Post by **ewetho** » Mon Apr 02, 2007 11:42 pm

Yeah we actual call it a catalyst monitor not even an O2. Just lengthen the wires by soldering in extra wire or stepped cut (just to help space out the butt splices so you do not have a big fat spot)and butt splices (If you can get the heatshrink with adheasive variety that is much better). Then tape up with electrical tape and if you can get some convoluted tubing and tape that on too to protect it.

Should be good to go. And like mentioned before watch routing.

Last thing use Oil Water Gas resistant wire.