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How to remove a stubborn O2 sensor

O2 Oxygen Sensor EA82

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22 replies to this topic

#1 __CJ__

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Posted 17 June 2014 - 08:08 PM

I have been chasing the cause of extreme surging with this car. It was a bad O2 sensor. So as a quick heads up, most people will tell you its not possible for that to be the cause, but trust me it was. With the new O2 sensor it was running much better (solved the extreme surging) but with some slight hesitation and almost a miss. Later in the day I am pretty sure I found the source of the hesitation/miss... Timing belt that decided to break on my way to show off the car to a buddy. Hopefully the new timing belt will take care of the last remaining problems. 

 

But let me digress, I had a fun time changing the O2 sensor on the newly purchased 1993 Subaru Loyale.

 

After many trips to the store to grab different tools and things I ended up getting the O2 sensor out. 

 

At first I spent some time attempting to use a harbor freight O2 sensor removal tool but just managed to figure out that its a bit tight to make that tool work and once you have figured out a way to make it work... its a 22mm O2 sensor and not a 7/8 like the harbor freight tool.

 

Ok run to the local autozone and rent there O2 tool kit (25.99). Throw on the 22mm O2 sensor tool and manage to fight the sensor for another 30+ minutes before saying screw it and removing the whole y-pipe. 

 

Once the y-pipe was out I managed to finish rounding off most the existing O2 sensor and was ready to take to my friends metal shop to just drill it out. 

 

Then I had one last idea, remove the heat shield and see if I could fit a box end on the O2 sensor that way. 

 

Magically it worked. I could fit a 22mm box wrench on the O2 sensor and with some help of a rubber mallet I was able to break free the O2 sensor from the exhaust. It was a bitch but I am pretty sure this was the only way I would have been able to remove the O2 sensor and also the most simple fool proof way to do it. 

 

tl;dr Remove the y-pipe. Once thats free remove the heat shield around the cat. Use a 22mm wrench and a rubber mallet to beat the O2 sensor out of the cat. 

 

Tools Needed: 12mm, 14mm, 22mm, rubber mallet, PB blaster (or something of the sort), rags. 

 

Hope my pain is another mans gain.



#2 spazomatic

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Posted 18 June 2014 - 05:57 AM

You can put some nickel anti-seize on the threads so its not a problem in the future, too.

#3 __CJ__

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Posted 18 June 2014 - 12:23 PM

You can put some nickel anti-seize on the threads so its not a problem in the future, too.

 

I was lucky enough that the Bosch replacement had some on it from the factory :)



#4 Subruise

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Posted 18 June 2014 - 05:02 PM

use a crowsfoot. thatll get it broke loose when a 02  sensor socket wont.  I kinda  wish Id bought a set ofthem  instead of the "special" socket i purchased



#5 scoobiedubie

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Posted 18 June 2014 - 09:09 PM

I just chopped enough of it off with a grinder, in order to get the socket on.



#6 Mr.Atlantis

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Posted 03 April 2015 - 09:37 AM

I just chopped enough of it off with a grinder, in order to get the socket on.

I once did that to a perfectly good sensor, replaced with an inferior over-seas part and will never forgive myself.   :(



#7 DaveT

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Posted 03 April 2015 - 10:06 AM

Heating it with a torch would likely help also.

#8 Subasaurus

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Posted 03 April 2015 - 10:12 AM

if the O2 sensor has 1 orange wire going to it on my 89 GL, howcome it does nothing when i unplug it? not even a check engine light? ive left it unplugged for a couple of days to see if there was any difference but all it did was nothing, could some one tell me whats going on? (i have recently removed the catalytic converter about 2weeks ago since its over 25years old and im exempt from emissions)
sorry about asking one of my questions here _CJ_ just dont want to make a whole thread if it can be solved by 1 answer..

#9 capmarvelous

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Posted 03 April 2015 - 12:10 PM

Subasaurus, I know you can check O2 sensors with a volt meter.  I think they should be fluctuating between 600 to 800 millivolts.  There is also a resistance check.  If you search online you can find the readings you should be getting.  When an O2 sensor fails the computer will go into a preset mode for the stoichiometry settings.  It may be that mode is perfectly fine for your car to run without any issues.


Edited by capmarvelous, 03 April 2015 - 12:11 PM.


#10 Subasaurus

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Posted 03 April 2015 - 12:58 PM

Subasaurus, I know you can check O2 sensors with a volt meter.  I think they should be fluctuating between 600 to 800 millivolts.  There is also a resistance check.  If you search online you can find the readings you should be getting.  When an O2 sensor fails the computer will go into a preset mode for the stoichiometry settings.  It may be that mode is perfectly fine for your car to run without any issues.

so lets say its not working at the moment, i cant check currently since its raining but if its not working and i got it to work.. i could get a check engine light right?

#11 DaveT

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Posted 03 April 2015 - 02:26 PM

If the sensor 8s open or shorted, I would expect a trouble code. I have not tested to be sure, however. I do know from a past experience, the sensor can fail in a way that does not generate a code, but does burn out the catalytic converter.

#12 naru

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Posted 03 April 2015 - 02:35 PM

You should get a check engine light w/the O2 unplugged.

 

Does your check engine light work?

 

Pehaps the ECU is ignoring the O2 sensor because the CTS is telling it the engine is still cold.



#13 Subasaurus

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Posted 03 April 2015 - 03:21 PM

You should get a check engine light w/the O2 unplugged.
 
Does your check engine light work?
 
Pehaps the ECU is ignoring the O2 sensor because the CTS is telling it the engine is still cold.

yeah it works since it always turns on when i unplug the mass airflow sensor. and ive driven the car for days with it unplugged and plugged and it does nothing or affect driving or power or gas or anything. i also have 2 extra computer boxes from other cars and ive swapped it with one (silver box model is the one my car takes) and still nothing, also when i put it in 4WD, no dash light comes on? but it does work since i cant do a burnout when the button is pushed but it does a burnout easily when its in FWD

#14 Subasaurus

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Posted 03 April 2015 - 03:24 PM

If the sensor 8s open or shorted, I would expect a trouble code. I have not tested to be sure, however. I do know from a past experience, the sensor can fail in a way that does not generate a code, but does burn out the catalytic converter.

that is probably why i had to remove the catalytic converter since it was making so much noise and when i went to gut it a couple weeks ago, it was all in pieces, i have so much power now that its gone, and better MPG ofcourse

#15 jono

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Posted 03 April 2015 - 04:45 PM

Done the same and ended up with Y pipe removal for access of my EA82 Y pipe on EA81 Brumby.

 

No ECU in mine, just making use of the O2 sensor with the single orange wire in the pipe to read to an LED reader display.

I discovered just yesterday , that for my particular case the reader needs to be earthed to the engine block and not just a simple earth within the vehicles earth grounding system ! The instructions did not go out of their way to explain why the unit has eng block on its wiring label. The gauge worked, just nowhere near accurate when I installed it in the last 6 to 12 months - until yesterday when i ran a wire from displays earth terminal , out the door, under the bonnet and cleaned up an earth pointon the AC bracket. BINGO ! Gauge works just fine !

 

The moral of the story seems to be for single wire O2 sensors at least - make sure the O2 sensor has a clean metal to metal contact on the exhaust apart from the threads that you may have some rust or sensor safe anti sieze grease on it and that the reader whether a gauge or the ECU has a good engine ground connection. I was just trying to power and earth my reader up via a cig ligter socket.


Edited by jono, 03 April 2015 - 04:47 PM.


#16 Subasaurus

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Posted 03 April 2015 - 08:52 PM

Done the same and ended up with Y pipe removal for access of my EA82 Y pipe on EA81 Brumby.
 
No ECU in mine, just making use of the O2 sensor with the single orange wire in the pipe to read to an LED reader display.
I discovered just yesterday , that for my particular case the reader needs to be earthed to the engine block and not just a simple earth within the vehicles earth grounding system ! The instructions did not go out of their way to explain why the unit has eng block on its wiring label. The gauge worked, just nowhere near accurate when I installed it in the last 6 to 12 months - until yesterday when i ran a wire from displays earth terminal , out the door, under the bonnet and cleaned up an earth pointon the AC bracket. BINGO ! Gauge works just fine !
 
The moral of the story seems to be for single wire O2 sensors at least - make sure the O2 sensor has a clean metal to metal contact on the exhaust apart from the threads that you may have some rust or sensor safe anti sieze grease on it and that the reader whether a gauge or the ECU has a good engine ground connection. I was just trying to power and earth my reader up via a cig ligter socket.

will anything improve if i fix it?? i think the computer knows its broken so it just went to default i guess?? i have no idea, but would fixing it improve anything or will everything stay the same?

#17 jono

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Posted 03 April 2015 - 10:01 PM

well, you'd like to think if you ' fixed it'  the ECU would have some input to keep fuel air mix in check instead of its probable default richer mode which might have consequences further down the track fouling plugs, sooting up other stuff internal ...

 

No extra black sooty smoke out the tailpipe from a supposed richer default mix ?r



#18 capmarvelous

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Posted 03 April 2015 - 11:11 PM

Hey Jono why did you hook up your O2 sensor to a display, I know you said you dont have an ECU. A little confused, I thought any car with an oxygen sensor must have some form of ECU to adjust the air fuel ratio.



#19 DaveT

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Posted 03 April 2015 - 11:23 PM

Pehaps the ECU is ignoring the O2 sensor because the CTS is telling it the engine is still cold.

I have seen this.  I had a CTS failing intermittent, it caused a lot of odd random problems, but never triggered an error code.  It didn't fail shorted or open, it just was lying about the engine temperature inside the valid range.  If the ECU thinks the engine is cold, it doesn't use the O2 sensor to adjust the mixture.

 

Fixing what ever is wrong should get you better mileage, since the ECU will control the mix properly, instead of running in a fail safe / rich mode.



#20 jono

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Posted 04 April 2015 - 04:35 AM

Hey Jono why did you hook up your O2 sensor to a display, I know you said you dont have an ECU. A little confused, I thought any car with an oxygen sensor must have some form of ECU to adjust the air fuel ratio.

 

I run a DP200 as seen in here

 

http://www.peelinstr....au/page12.html

 

The duty cycle gauge could be handy for some efi enthusiasts ??

 

The Y pipe is on a non O2 equipped model -something our authorities allowed on 4WDs, it is off an efi EA82 so conveniently came with an O2 sensor

 

I use O2 sensor just to read from, so it does not control any of my mixtures, though IMPCO do make a mixture controller that uses O2 sensor readings to adjust things ever so slightly - no idea why it is required on some later models as the fresh air non interfered with systems run very accurately controlled mixtures as it is according to the tail pipe analyser on the road under all conditions I have tested. The controllers tend to be forgottn, not maintained and after some time of neglect can then be cause of backfires from the controllers conditions causing a lean out

 

not sure why I didn't just buy a digital readout gauge that I guess would read whatever it received, whereas this LED bar graph jobbie sort of appears to read only very close to the stoich of propane burning at 15.5:1 air fuel ratio. Yet to note just what the tail pipe reading is as bars go each extreme. Something to do over the break maybe.

 

I guess anyone running a standard car burettor could get an O2 sensor bung welded on or fit an O2 sensored Y pipe and get a running reading as to how well their mix is burning. I run one of these made while you wait gauges in my turbo EA82T set up and can see it drop towards lean at the end of long mountain hauls as it gets hotter the IMPCO converter tends to lean things out a bit about 95C - just like to monitor what is available :)


Edited by jono, 04 April 2015 - 04:42 AM.


#21 Subasaurus

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Posted 04 April 2015 - 07:28 AM

well, you'd like to think if you ' fixed it' the ECU would have some input to keep fuel air mix in check instead of its probable default richer mode which might have consequences further down the track fouling plugs, sooting up other stuff internal ...

No extra black sooty smoke out the tailpipe from a supposed richer default mix ?r

does 25-28mpg on city driving and 33-34mpg highway sound right? i do have like 60 pounds of tools in the back lol, but remember i did gut the catalytic converter, seems that the O2 sensor was in the first catalytic, but its inbetween the Y pipe, so im not sure if its reading the before, or after catalytic converter. also my engine starts right up in the first crank (.5-1second) if i overcrank it (1-2seconds) it floods the engine and i have to crank on it for about 4-8seconds with my pedal halfway down and it'll start up again. and no black smoke or any of that, engine is very happy for all i know.

Edited by Subasaurus, 04 April 2015 - 07:29 AM.


#22 BoostedBoxer421

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Posted 04 April 2015 - 08:52 PM

A good mixture/formula I've found for getting O2 sensors, exhaust bolts, turbo flange bolts, and driveline bolts is a 50% ATF (automatic tranny fluid) and 50% Acetone... works amazing, trust me haha I've destroyed 2 O2 sensors that were good before I found out about this mixture for breaking things loose

#23 jono

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Posted 04 April 2015 - 09:35 PM

Subasaurus looks like nice fuel figures and starts, stops, no smoke, no problems - maybe don't go try fix something that is broke this time around :)







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