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Guest Message by DevFuse

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EJ Swap O2 Sensor

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3 replies to this topic

#1 herb


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Posted 14 May 2013 - 02:04 PM

So my EJ swap is on the road (thanks to the tireless efforts of dr.suberdave), but with no o2 sensor at the moment.  I got subie101's headers and got the rest of the exhaust done at proexhaust, but they didnt put a bung in for the o2 sensor, and obviously im getting a CEL.  My question is would it be better/smarter/more economical to get the bung and sensor put in, or leave it sensor-less and potentially correct it via a retune? Thanks in advance, I appreciate it guys.

#2 tractor pole

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Posted 14 May 2013 - 04:44 PM

I also have a header from subie101, when I built my mid pipe assembly I used a universal catalytic converter with a integral o2 sensor bung and then an additional one after the cat.


I just drilled a 3/4" hole and welded the o2 bung on the pipe. I was able to pick up a weld in bung with a plug from amazon for $10 link [the thread pitch and diameter is the same as OE replacement sensors for a 97 Legacy]


it would probably be easier/better/smarter to just run the o2 sensor. plus no CEL would be awesome... (my CEL is not attributed to the oxygen sensors)



#3 Numbchux


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Posted 14 May 2013 - 04:46 PM

Well, no N/A EJ ECU is re-tuneable.....so unless you're running a standalone, that's not an option.



Assuming this is an up-stream 02 Sensor (it helps to know what year, model, size, etc. EJ you have  :rolleyes: ), it is used to constantly adjust fuel trims. Yes, install it.

#4 presslab


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Posted 14 May 2013 - 11:37 PM

Well, no N/A EJ ECU is re-tuneable.....so unless you're running a standalone, that's not an option.


Well, I beg to differ.  B)


Anyway, yes weld a bung on and put a sensor in.  For anything other than a pure race car it makes a whole lot of sense.

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