bung hole

ok so where would it be better to put my o2 sensor in my header. the orginal spot on the 4th cylinder's exhaust pipe or down right before the cat? my reasoning for wondering is if you put it in front of the cat then the o2 sensor will read off all four cylinders instead of just one

My DC header 02 hole is down by the cat. Kind of a bitch to change out though...

hahaha this title made me laugh out loud.

anyways, honda put it where it is for a reason, and the computer is going to be expecting to be getting readings from that spot, so any changes could make the car run different or throw a code. The header I had on my 89 had the o2 sensor down by the cat and it seemed to throw a cel every once in a while for the o2.

So i say keep it OEM.

what if u didnt have it on there would it cause the ecu to run rich since it wouldnt sense any exhaust?

what if u didnt have it on there would it cause the ecu to run rich since it wouldnt sense any exhaust?

I'd expect so.

I would get a code from my O2 and I always thought it was the header but it turned out to be a poorly connected wire. I mean I thought that bitch was tight but there can be absolutely no space at all... none, zip, nada! My wires are wrapped and secured with no butt connectors or any shit like that and it works. Soldering would be the best way to go when extending an 02 sensor wire. Also, the actual 02 sensor wire is white with a rubber coating over it.

Another thing to consider.... If you have the bung on a single tube coming right off the head, it will only sense what that cylinder is emitting. If you put it down the header farther where they all come together, you will get a better overall reading of the exh. gases.

that is kinda my basis of this forum 91civichatch. i makes sense? no? to put it where they all come together and hopefully one person will know how the computer will reate to me moving the sensor to in front of the cat

that is kinda my basis of this forum 91civichatch. i makes sense? no? to put it where they all come together and hopefully one person will know how the computer will reate to me moving the sensor to in front of the cat
To be absolutely honest, that^^ doesn't really make all that much sense. After reading your first post again I do see that you and I basically said the same thing. Sorry about that. For some reason I replied to the reply's in this thread instead of your original question, as if i just skipped right over it or didnt read it.

yeah i think we did kinda of say the same thing... any ways it can some times be easy to get side tracked in forums... can some one please answer the original post though? maybe some suggestions?

you already know my suggestion.... in front of the cat

alright i will put it in front of the cat and test see how the computer likes it. i'll reply later with results ( i dont expect much of anything)

i still think that you should put it in the oem spot.

like with dc headers for b series with 2 o2 sensors, they recomend you still put the bungs on the #4 and #2 cylinder runners on the header. if the o2 sensor is too far down stream it also might not heat up to correct operating temperature and the extra gases from the other 3 cylinders may cause it to read more of a lean or rich condition, causing either poor gas mileage or spark knock.

or you could always get a nice 4 wire O2 sensor so the heat isn't a problem...

i still think that you should put it in the oem spot.

like with dc headers for b series with 2 o2 sensors, they recomend you still put the bungs on the #4 and #2 cylinder runners on the header. if the o2 sensor is too far down stream it also might not heat up to correct operating temperature and the extra gases from the other 3 cylinders may cause it to read more of a lean or rich condition, causing either poor gas mileage or spark knock.

What do you mean by "spark knock"? Do you mean this only with a B series or D as well? I'm just curious. I average 30mpg (sometimes way more if I actually take it easy).

dude spark knock is spark knock it can happen on any motor, it happens from a lean mixture and the car can't retard the timing any further.


4 wire o2 is better idea, but then you have to wire it in, how would you go about doing that?

dude spark knock is spark knock it can happen on any motor, it happens from a lean mixture and the car can't retard the timing any further.


4 wire o2 is better idea, but then you have to wire it in, how would you go about doing that?

der... I should've realized you were referring to detonation. My ignition timing is factory for fuel economy...

its cool we all have brain farts lol