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-   -   cat removal options ,02 sensor 2 code removal (https://www.jk-forum.com/forums/modified-jk-tech-2/cat-removal-options-02-sensor-2-code-removal-80776/)

mEthOdsOMahAn 04-07-2009 01:32 PM

cat removal options ,02 sensor 2 code removal
 
i rolled my jk . when i was replacing the frame i noticed 2 of my cats were damaged due to contact with the bent frame . a new y pipe with all 4 cats is definatly out of my price range . is there any way to remove the sensor 2 02 codes from the pcm ? OR does anyone have any other options ? there are no emission testing currently in my area, so that is noy a problem for me .

RedneckJeep 04-07-2009 01:36 PM

Yeah. Borla makes some long tube headers that comes with a new Y pipe that has no cats.

mEthOdsOMahAn 04-07-2009 01:51 PM


Originally Posted by RedneckJeep (Post 1048490)
Yeah. Borla makes some long tube headers that comes with a new Y pipe that has no cats.

removing the cats is not the problem . getting the check engine light off is my main concern

JPop 04-07-2009 02:01 PM

Are the O2 sensors currently attached?

mEthOdsOMahAn 04-07-2009 02:08 PM


Originally Posted by JPop (Post 1048533)
Are the O2 sensors currently attached?

currently i removed the bank 1 cat 1 &2 . i put cat 2 in cat 1s place and a straight pipe where 2 was . this has worked fine for about 3k miles . now i believe that bank 2 cat 1 is also damaged . exhaust was rattling and now it has a raspy exhaust note . so i am wanting just to remove all 4 and be done with it . i also notice there are no 02 sensors after the rear 2 cats like most other vehicles have . and to answer your question is YES all 4 02 sensors are in the stock locations . i would like to remove the rear 2 as its my belief that they only monitor cat condition BUT i do not want the CEL on .

d0wnShifT 04-07-2009 02:57 PM

There were ways to defeat the O2 sensor CEL in my Volkswagen GTI that other people were doing that I fortunately didn't have to do because of my aftermarket programming. What they did was get spark arrestors and thread them into where the rear o2 sensor goes on the header... then put the sensor on the end of it. Logic for this was that it still would heat the sensor, but put it far enough back in the exhaust stream to keep it from getting a CEL. Results were mixed with this solution. Here's a pic of the arrestors and 2 links for more information...
http://synthesistechnologies.com/ass...e/DSC01405.jpg

http://forums.vwvortex.com/zerothread?id=3850970
http://forums.vwvortex.com/zerothread?id=2363498

mEthOdsOMahAn 04-07-2009 03:04 PM

ya , i was going to try the little tube that raises the rear sensor out of the exhaust path . i just dont see this working very well but everyone says it does . i know on gM vehicles trouble codes can be removed completely . this is what i would like to do .

RedneckJeep 04-07-2009 03:41 PM


Originally Posted by mEthOdsOMahAn (Post 1048516)
removing the cats is not the problem . getting the check engine light off is my main concern

Then buy some O2 sensor simulators. Pretty simple really.

mEthOdsOMahAn 04-07-2009 03:46 PM


Originally Posted by redneckjeep (Post 1048726)
then buy some o2 sensor simulators. Pretty simple really.

in theory !

whpony96 04-07-2009 03:56 PM

1 Attachment(s)
I have them on my mustang and they are called MIL Eliminators... (Malfunction Indicator Light)

It's a simple 2 component circuit really..



MIL Eliminator
If you are one of the people with '94 and up MN12, and thinking of making a straight exhaust with no catalic converters, you may run into problems since your model car has OBDII sensors behind each cat. If you remove the sensor computer may be getting wrong readings.
But don't worry.
There is a special device called a MIL Eliminator that you can get at www.dallasmustang.com ($60 + S&H), that will reroute the signal correctly to the computer without having the OBDII sensors in.

The device just plugs into the back of the rear O2 sensors and they send a signal that tells the computer that everything is ok, just as the O2 sensors would if the cats were there.

* - Also, if you are going to remove all the cats be careful that you have enough backpressure or you will lose low-end torque. I have heard this is a common occurence when you gut or remove the cats. You can put one 3" in/out Flowmaster or a Resonator where the third cat used to be to fix this.


There is also a way to build a circuit that will work just like the MIL Eliminator.

Here is a link to the diagram that you can build it on your own if you are good with electronics.
Make a circuit that reads the voltage of the first o2 then injects a corresponding voltage into the harness connection for the second o2. A couple of diodes and resistors is all that is needed.


Q: Knowing that the O2 sensor has a limited life and loses its sensitivity over time, could you swap the positions of the before CAT and after CAT sensors to put a less "used" one in the before position? I am assuming the after CAT one gets less corrosive elements.

A: The sensor's output is driven by the O2 content. Steady state below about .40volts means there is excess oxygen from stoichiometric levels and steady state above about .8 volts means less oxygen than the stoich level.
I am just guessing now, but if the catalytic converters are scrubbing excess oxygen ions from the various oxides produced in combustion, then the voltage should always be higher in the post-CAT sensor than in the pre-CAT sensor indicating to the PCM that the CATS are working properly.
I would venture to say from that guess that if you could drive 1.0 volts into the second O2 sensor harness you would fool the PCM.

RichM

CATALYTIC CONVERTER: OBD-II monitors the operation of the catalytic converters by a double set of heated exhaust gas oxygen sensors (HEGOS or O2). Comparing the oxygen content of the exhaust gas entering the converter with the oxygen content of the exhaust gas exiting the converter. OBD-II reports and stores catalytic conversion activity.

If you remove the catalytic converters, the oxygen content will be the same between the 02 sensors. Shortly after OBD-II will intercede and the CHECK ENGINE light (MIL) will illuminate. If you ignore the CHECK ENGINE light long enough, OBD-II will enter LOS (limited operation strategy) or "limp home mode".

RedneckJeep 04-07-2009 03:58 PM


Originally Posted by mEthOdsOMahAn (Post 1048738)
in theory !

No, in reality. People use them all the time.

john smack 04-07-2009 04:00 PM

Well a little easier option would be an O2 trick box I bought them for my 97 Chev when I took out the cats..... You unclip the O2 sensor from the wiring harness(There was a connector on my truck) and plug this little black box into instead of the O2 and it would sent the appropriate signals to the computer. These worked great for me and I never had a code or check engine light again. I do not remember what they are called but I got them from a performance shop and they were around 80 Canadian Cedar Chips per unit. so I think in total it was a little under 200 bucks. I will see if I can find out what or who makes them and such details.

john smack 04-07-2009 04:03 PM

Redneck knows what I am talking about

nangulator 04-07-2009 04:20 PM


Originally Posted by d0wnShifT (Post 1048631)
There were ways to defeat the O2 sensor CEL in my Volkswagen GTI that other people were doing that I fortunately didn't have to do because of my aftermarket programming. What they did was get spark arrestors and thread them into where the rear o2 sensor goes on the header... then put the sensor on the end of it. Logic for this was that it still would heat the sensor, but put it far enough back in the exhaust stream to keep it from getting a CEL. Results were mixed with this solution. Here's a pic of the arrestors and 2 links for more information...
http://synthesistechnologies.com/ass...e/DSC01405.jpg

http://forums.vwvortex.com/zerothread?id=3850970
http://forums.vwvortex.com/zerothread?id=2363498

this works great on the O2 sensors after the cat, I have never tried it on the upstream ones:thinking:

mEthOdsOMahAn 04-07-2009 04:23 PM


Originally Posted by nangulator (Post 1048821)
this works great on the O2 sensors after the cat, I have never tried it on the upstream ones:thinking:

upstream sensors do not require this due to the cats do not effect sensor 1

nangulator 04-07-2009 06:22 PM


Originally Posted by mEthOdsOMahAn (Post 1048830)
upstream sensors do not require this due to the cats do not effect sensor 1

It all depends on the vehicle that you are working on, alot of the German car (05 and up) upstream sensors actually do look at the downstream sensors:yup:

d0wnShifT 04-07-2009 07:11 PM

I know with my old car, an 04, the front sensor is for the AFR and rear is cat efficency. One doesn't care about the other.

officer_vince 04-07-2009 07:37 PM

Is it worth the performance/mileage gains to eliminate the cats in the JK?

JC JK 04-08-2009 02:51 AM

Is it worth the performance/mileage gains to eliminate the cats in the JK? I would say not enough ot cut up a good Y-Pipe with cats. I was looking in to this but to hollow them out and put it all back looking stock was not worth the Time or money. God luck on your 02 Eliminator.

RedneckJeep 04-08-2009 03:26 AM


Originally Posted by officer_vince (Post 1049301)
Is it worth the performance/mileage gains to eliminate the cats in the JK?

Probably not, but tellin some folks that is like talking to a damn rock.

JPop 04-08-2009 04:12 AM

Redneck, I think your solution of the Borla long tubes was a good one. The bungs are there for all 4 O2 sensors. It also would be a fair pre-sales support question to ask them if this set up would throw any DTCs or the check engine light. It also looks as if there is enough space after the collector and before the second set of O2 sensors to weld in after market cats.

It won't be the cheapest solution, but probably the best. If you don't want to do that, then generating a stable O2 sensor reading using an O2 simulator is your best bet.

mEthOdsOMahAn 04-08-2009 04:49 AM


Originally Posted by nangulator (Post 1049089)
It all depends on the vehicle that you are working on, alot of the German car (05 and up) upstream sensors actually do look at the downstream sensors:yup:

i do not think the caravan engine is german ? or is it:eek2:

mEthOdsOMahAn 04-08-2009 08:10 PM

well i just got back from removing the last 3 cats and 2 ended up being bad . i did the non fouler trick . i have not erased the codes yet to see if they come back ( fingers crossed ) one cat was already completely hollow and the other was half empty . i would never remove these for a performance gain . the only reason for removal was because of the damage from the crash . i installed a long glaspack before the factory muffler so it still sounds stock . it sounded like a honda wit a fart pipe after the cats were removed LOL:wink:

nangulator 04-10-2009 07:35 PM


Originally Posted by mEthOdsOMahAn (Post 1049638)
i do not think the caravan engine is german ? or is it:eek2:

You never know, chrysler and mercedes were laying in the same bed for a few years:thinking:

Wildhorse66 03-12-2019 10:08 AM

Magnum makes an O2 eliminator that covers all 4. I have an 09 the cat is burnt and the error codes are throwing my Jeep into limp mode.


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