T_Rex

Got the DC 4-2-1 put on and placed one O2 sensor in it and extended the wire...what I'm wondering is, the stock manifold (B16A) had two O2 sensors on it. What do I do about the other wire? For now, I just left one off and taped up the other wire--so for the "check engine light" hasn't come on. Any suggestions on this? Thanks.

PhatOptimo

https://honda-tech.com/zerothread?id=273514
check it out.

spettinger

run your stock O2 wire (on top of the transmission) down to the O2 sensor on the header, then split the other end, at the ECU, to run both pins on the ECU.

Malgerus

*shudder* Do it right... then you don't need to worry about hacks like this.

T_Rex

OK, but what's the right way?

spettinger

ok, you could run 2 o2 sensors that get the SAME SIGNAL, or you could split one sensor and save a lot of headaches.

crxjdmsir

Yes they both send the same signal but only if 1 and 4 are running exactly the same as 2 and 3 ,unlikely and not recomended. Have the two o2 bungs welded in the proper runners or switch to obd. Do it right, it's like that for a reason.

T_Rex

Not sure what you mean by switch to OBD? I thought it already was OBD.

raene

They don't get the same signal. I have a toggle set up between the two O2s, and they're noticeably different both in response and range.

The correct way is to weld a bung in place for the 2nd O2. It's really not that big of a hassle.

PhatOptimo

PR3 & PW0 ECU (the ECUs thats runs 1st gen B16a) are both OBD 0 or Pre OBD. Do not run 2 wires from 1 02 sensor. It has been the cause of many swaps to run horribly. If your going for an aftermarket header the only way to do it and keep your pre OBD ECU is to have O2 bungs welded into the primaries of the header. If you don't do this your car will run shitty. Need more help let us know.

.ShawnD.

this is probably the reason my car runs like chit!! .. whats involved in welding the "bung" for the second o2 sensor.. do i have to take the header off and have soneone do it or what?? what about wiring?? i didnt do the swap so i dont know were the wires are??

FastFoot

if it runs shitty then why does mine run SMOOTTH and niceee...i connected both o2 wires together to run off one o2 sensor it it works finee...

Sgt_Ox

Are you running a chipped ecu? http://www.jdmhondaparts.com/ has a Mugen program that runs only one O2 sensor. Otherwise it just may seem to to be smooth to you until you rectify the problem then you'll notice a difference in performance.

SpeedMonkeyRacing

i have those programs too. E-mail me @ JEFF@STAGE2RACING.COM and i'll do it for ya cheap

Jeff-

SuperCivic

just to let you guys know how IMPORTANT this is..i had a stock b16 manifold, running 2 o2 sensors..and my car had hesitation issues when i had the o2 sensor's switched! car ran perfectly when i switched them to the correct position..cars w/ one o2 sending one signal to both o2 pins must run terribly.

T_Rex

Man, now I'm really confused! Which way is the best way? Actually, which way is the best and *cheapest* way???

crxjdmsir

Weld in the two bungs in there proper location. Check out Hondata's site as well.
http://www.hondata.com/techclosed.html

Brandon Chun

Weld in a bung for the other sensor or have a muffler shop do it for you. If you have a shop do it it should be pretty cheap.

HandCommand

Do it the right way and have 2 bungs welded into the primaries of your header. Remember, these are single wire non-heated O2 sensors that need to be placed closer to the head for quicker heat up. The PR3 and PWO ecus need to see a single for cylinders 1 and 4 and 2 and 3.

Personally, on many of my own B16 CRX's that I have had, I have always used the OEM exhaust manifold with the 2 sensors. The motor is running just the way it was intended when Honda built it.

On some swaps Ive encountered I had to switch the signals from the sensors around, but after that it runs perfect. I usually pull the pins at C8 and C16 on the ECU and switch them, rather than doing a cut and splice out at the engine bay near the sensors. Some cars need to be switched, some dont.

.ShawnD.

what about the wiring ... i havent looked for it but im about to put my new CAT on there and would probably have the second 02 put in but.. i dont know were the wiring is would it be in the harnest or would i have to run it from the ECU or something ..

sorry im not a wiring geneous so i know little about wiring

ps.. i also have this header where should i get the bung placed .. could anyone show a picture the one in there now is closer to the cat
also: what kinda O2 do i need single wire for what car


[Modified by .:s h a w n D:., 2:14 AM 9/10/2002]

T_Rex

I gave this some more thought and I have some more questions for you guys-

If I have a muffler shop weld the bungs for the two O2 sensors, I'll also need them to weld closed the hole on the header (near the cat), won't I? This seems like it will be pretty expensive ...what do you think?

Why do the O2 sensors need to be on the primaries and does it matter which one is closer to the top?

Is it possible to still use one O2 sensor, such as the 4-wire one?

I have the PW0 ECU. What does it take to convert to OBD? Is it very involved/expensive?

Man, I wish I knew all this BEFORE I decided to get a DC header


[Modified by hondanut, 7:34 AM 9/11/2002]

k4ff1n3

i had my muffler shop do it for 15 bucks (the guy did it on his lunch break 2!) it has to be on the primaries to get a proper reading of what is comming out of the engine..... if its further down it wont work as well....... i definatly noticed a differance when i put my JDM header back on.....

T_Rex

Thanks, man. Anyone else?

ricodemus

Did the muffler shop have all the parts necessary to do the job? I don't know if the o2 sensor screws in or what (so it would have to be tapped). Do I just walk in there and say, "I need 2 bungs welded in my header, and one (the one already one the aftermarket header) needs to be closed"? Sorry I'm polish.

k4ff1n3

yes the muffler shop will have every thing that you need to get the job done............and its cheap .. dont do what i did at first and try to rig it with heated o2 sensors youll never get an accurate reading...

and its ok to be polish, im sure youll grow out of it.............