Help!!! Where Is The Main O2 Sensor At???

[mazdaspeedkid]

hey everyone i just got my gauges in and i buyed a air fuel ratio gauge and i need to tap it into the main o2 sensor wire that reads the o2 does anyone know where it is at i need to know asap thanks

 

[www.cp-e.com]

hey everyone i just got my gauges in and i buyed a air fuel ratio gauge and i need to tap it into the main o2 sensor wire that reads the o2 does anyone know where it is at i need to know asap thanks

The top O2 sensor is about six inxhes down-stream from the turbo outlet on the downpipe. If you're totally unfamiliar with this motor, it's in back of the engine bay between the firewall and the engine. You can gain clearance to it by removing the intercooler (but you don't have to), and you'll be able to see it if you stand on the passenger side of the engine bay.

Here is a picture of the oxygen sensor on one of our downpipes. The sensor is in almost the same location on the stock downpipe. And please ignore the red circle I drew, that was for another purpose. The top oxygen sensor is the sensor with the braided wire sheath and the gold bowl looking deal below it:

If you need more guidance, I'll see if I can snap a better picture for you. Hope this helps!


Jordan

 

[Maxx Mazda]

Don't bother. Go buy a wideband or it's pointless. "Woo! Blinky lights!"

 

[Nutari]

the O2 sensors on the speed 3 is a wideband btw.

 

[Maxx Mazda]

the O2 sensors on the speed 3 is a wideband btw.

Ya but you needa wideband gauge to read it. You need a 0-5V gauge, not a 0-1V

 

[funktownp5]

Ya but you needa wideband gauge to read it. You need a 0-5V gauge, not a 0-1V

(yes)

 

[mazdaspeedkid]

The top O2 sensor is about six inxhes down-stream from the turbo outlet on the downpipe. If you're totally unfamiliar with this motor, it's in back of the engine bay between the firewall and the engine. You can gain clearance to it by removing the intercooler (but you don't have to), and you'll be able to see it if you stand on the passenger side of the engine bay.

Here is a picture of the oxygen sensor on one of our downpipes. The sensor is in almost the same location on the stock downpipe. And please ignore the red circle I drew, that was for another purpose. The top oxygen sensor is the sensor with the braided wire sheath and the gold bowl looking deal below it:

If you need more guidance, I'll see if I can snap a better picture for you. Hope this helps!


Jordan

thanks but what wire would i need to tap onto to get signal to the gauge
these is alot of help thanks

 

[ssinstaller]

you can't pull a useable reading for the stock O2.. You will damage the O2 controller if you tap into the sensor...

 

[redms3gt]

Likely the extra load will change what the ECU sees. Could be a problem but had no issues with my 2g talon? Anyone know for sure? Could just use a dashhawk to moniter what the ecu is seeing? I think it has the ability to see cat temps also?

 

[mazdaspeedkid]

you can't pull a useable reading for the stock O2.. You will damage the O2 controller if you tap into the sensor...

sooo how am i going to be able to hock up my gauge then is there somewhere is i can tap it into???

 

[Rotus8]

sooo how am i going to be able to hock up my gauge then is there somewhere is i can tap it into???

The only realistic way to hook it up is to add a bung to the exhaust and put in another sensor. If you tap into an existing sensor, the engine computer will explain why you shouldn't by either messing up your engine or throwing a CEL, or both.

 

[www.cp-e.com]

thanks but what wire would i need to tap onto to get signal to the gauge
these is alot of help thanks

I really don't know off hand which wire you'd tap into as I've never installed the device you're working with. And like the other members are saying, the MS3 oxygen sensor isn't a typical narrow band sensor like you'd find on most other cars in the past, so I don't even know if it will work with the top O2 sensor. It sounds like SSinstaller knows for sure though. Did this gauge come with any documentation at all?

If you're concerned at all about your air/fuel ratio I wouldn't put too much faith in that gauge's readings anyway. If you want a decent indication of your air/fuel ratio you should spend some money and invest in another wideband sensor and install it in your downpipe.

And before anyone suggests it you cannot just tap into the wideband and make any sense of the signal. In order to do so, you'd need to sense the current (not voltage) going to the ion pump. But by tapping into the ion pump, you're effectively creating another circuit which will skew the output. Even worse, the ion pump is undoubtedly attached to a feedback loop. So if you did skew the circuit by probing it, you'd effectively be altering the feedback loop, which could be dangerous for the engine. And even if you could effectively sense the current to the ion pump without causing any issues, you'd need to make sense of the signal since I'm sure it isn't scaled linearly, and is likely a PWM signal.

I'm sorry that this thread turned into bad news for you, but its probably better that you learn this now instead of spending money on another gauge that may not work for you.


Jordan

 

[mazdaspeedkid]

ok ppl thanks for everything well i guess im buying a wideband now lol so what is a good wideband out there that is not that costally

 

[Rotus8]

ok ppl thanks for everything well i guess im buying a wideband now lol so what is a good wideband out there that is not that costally

I got one from here:
http://www.plxdevices.com/products.htm
It works well for me.