O2 simulator question! - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Wrangler Forums > TJ Wrangler Technical Forum > O2 simulator question!

Great prices on seating!--Oconee Off-RoadTJ 5.25" Speaker Adapters - NalinMFGTJ, YJ & LJ Drop Down Tail Gate Conversion Kit

Reply
Unread 07-08-2010, 10:47 PM   #1
Brookg
Registered User
1997 TJ Wrangler 
 
Join Date: Feb 2010
Location: Michigan
Posts: 17
O2 simulator question!

First of all i have a 97 tj 6cyl. My cat. converter is shot! can hear junk rattling around. i was thinking of cutting it right out. now i will have a problem with the O2 sensor right? i was told i could do an O2 simulator to solve the problem. i have only one sensor downstream of the cat. converter. so could i use a simulator to bypass the check engine light? i think i can, but what type of simulator would i get? any links to where i could purchase one? how would i install it? cut off/ pull out the stock O2 and put in the simulator? or wire the simulator to the stock O2 sensor? i just want to straight pipe it back to the muffler.... any tips, ideas, links??

thanks for the help!!!

Brookg is offline   Reply With Quote
Unread 07-09-2010, 12:22 AM   #2
hartke20g
Registered User
1998 TJ Wrangler 
 
Join Date: Apr 2009
Location: miami
Posts: 139
let me just beat everyone to the punch: you can't discuss removing the cat on JF since it's illegal and there are federal laws prohibiting tampering with it.

now to solve your problem. i would not suggest going the O2 sim way. if your cat's clogged, just replace it. IIRC, using an O2 sim doesn't completely fool your computer. your computer is constantly getting readings from the O2 sensors and is therefore constantly changing the engine's air/fuel mix to get the best performance and economy. when you bypass those systems, it basically does the equivalent of putting the computer in a closed loop which will only give you 1 air/fuel ratio. this can cause you to either run lean or rich, depending on the resistance (in ohms) that the O2 sim is sending back to the computer. yes, removing the cat may gain you some horsepower, but who are you kidding? it's a Jeep- horsepower shouldn't be your main concern (unless you're doing the 1/4 mile, in which case i say dump the I6 and get a HEMI ). the I6 was designed for maximum torque, not HP, which is perfect for off-road situations (like rock crawling for example). putting in a high flow (or even stock) cat will net you better performance than having either not cat or a broken cat. while ditching your cat may get you 0.5 seconds on the straightaway, there's really no typical, everyday situation in which it would be beneficial.

not to mention if your state has vehicle inspections, you're F'd.
heck, i don't want to remove my cat and my state doesn't even have inspections!
__________________
1998 TJ 4.0 Sahara, D30/D35, 33x12.50x15 Mud Kings, HF 8k winch, snorkel. "Military Edition"
BLS33: "Granted in general I am all for kicking babies, but in such an instance it would seem unfair, I would kick the parents first."
hartke20g is offline   Reply With Quote
Unread 07-09-2010, 05:40 AM   #3
Sundowner
Part-Time Swami
 
Sundowner's Avatar
2003 TJ Wrangler 
 
Join Date: May 2009
Location: The Republic of Dave
Posts: 6,144
Thanks for saving me the trouble of writing all that stuff yet again. Wow, we made it all the way until Friday before an "I want to cut my cat out" thread showed up...

In addition to doing something illegal, you're also causing problems - as you suspected and has been explained - with the O2 sensors. It sounds like your plan is to remove one part you need, and then install another problematic part - the simulator - to fix the problem that you, yourself, created. No offense, but that's not too bright.

Also, cutting the cat will NOT gain you power or torque, and it's ecologically unsound. The stock exhaust system works great, so don't make yourself - and the rest of us - look bad by cutting your cat.
__________________
If it's worth doing, then it's worth overdoing.

The Republic of Dave: Bringing you the finest in simian testing supplies.

The build, the gear, and the mileage: The Wasteland Survival Guide
Sundowner is offline   Reply With Quote
Unread 07-09-2010, 07:37 AM   #4
Wheelin98TJ
JEEP FREAK
 
Wheelin98TJ's Avatar
1998 TJ Wrangler 
 
Join Date: Apr 2004
Location: , Southeast MI
Posts: 24,164
I would put a Magnaflow cat converter on it.

You can get a high flow converter with a new downpipe to connect to the header for about $140.

Magnaflow 23227 - MAGNAFLOW Performance Direct Fit Catalytic Converter for 97-99 Jeepģ Wrangler TJ with 4.0L Engine - Quadratec
Wheelin98TJ is online now   Reply With Quote
Unread 07-09-2010, 08:37 AM   #5
fang_x
Registered User
1998 TJ Wrangler 
 
Join Date: Jun 2009
Location: Montreal, Canada
Posts: 1,259
I did a bit of research on this in the past and found this. I removed my CAT aswell

MAGNUM ADJUSTABLE O2 / OXYGEN SENSOR SIMULATOR - ELIMINATOR

its cheap and adjustable and the wires match up with the 4 wires coming out of your rear oxygen sensor, grey black white white.

if you go for this i would probly get some kind of sealant to make it water tight after it is on a jeep

hope this helps

"Its your jeep you can run it the way you want to! "
__________________
'98 TJ Manual -2.5" rcx long arm on 31
'99 Xj, Stock on 30"
'86 Monte Carlo 357 stroker. 450hp.
fang_x is offline   Reply With Quote
Unread 07-09-2010, 08:42 AM   #6
Wheelin98TJ
JEEP FREAK
 
Wheelin98TJ's Avatar
1998 TJ Wrangler 
 
Join Date: Apr 2004
Location: , Southeast MI
Posts: 24,164
Quote:
Originally Posted by fang_x View Post
I did a bit of research on this in the past and found this. I removed my CAT aswell

MAGNUM ADJUSTABLE O2 / OXYGEN SENSOR SIMULATOR - ELIMINATOR

its cheap and adjustable and the wires match up with the 4 wires coming out of your rear oxygen sensor, grey black white white.

if you go for this i would probly get some kind of sealant to make it water tight after it is on a jeep

hope this helps

"Its your jeep you can run it the way you want to! "

How cheap is it?

I clicked the buy it now link and they say priced from $69.99.
Wheelin98TJ is online now   Reply With Quote
Unread 07-09-2010, 10:08 AM   #7
extsp2
Registered User
2002 TJ Wrangler 
 
Join Date: Mar 2010
Location: brockton, mass
Posts: 512
extsp2 is offline   Reply With Quote
Unread 07-09-2010, 08:03 PM   #8
fang_x
Registered User
1998 TJ Wrangler 
 
Join Date: Jun 2009
Location: Montreal, Canada
Posts: 1,259
Quote:
Originally Posted by Wheelin98TJ View Post
How cheap is it?

I clicked the buy it now link and they say priced from $69.99.
ehh guess they updated their prices, when i was interested in it it was on sale for 34.99 or something like that. there were a few ebay auctions for it
oh and sorry the link i gave was for the one for motorcycles, this is the one for vehicles http://www.magnumtuning.com/en/detai...r_hho_systems1
not sure what the difference is though
__________________
'98 TJ Manual -2.5" rcx long arm on 31
'99 Xj, Stock on 30"
'86 Monte Carlo 357 stroker. 450hp.
fang_x is offline   Reply With Quote
Unread 07-09-2010, 08:16 PM   #9
viperbluelx
Registered User
2004 LJ Wrangler 
 
Join Date: Apr 2005
Location: Ringgold, GA, Georiga
Posts: 1,181
I don't agree with removing the cat, but there is so much misinformation in this thread I thought I'd reply.

The rear 02 sensor does nothing besides monitor catalytic converter function. The rear 02(the one you're trying to fool to keep the check engine light off) does not at all effect air fuel or engine performance, EVER. For that matter you could yank the cat, unplug the rear 02 and drive it with the check engine light on and you're still not going to see a performance decrease.
__________________
98 XJ 4-door, 6.5" lift, SYE, sliders, locked HP30, welded 29-spline 8.25, 35" buck shots.
viperbluelx is offline   Reply With Quote
Unread 07-09-2010, 11:32 PM   #10
Brookg
Registered User
1997 TJ Wrangler 
 
Join Date: Feb 2010
Location: Michigan
Posts: 17
thanks for all the replys.

i was considering the simulator, but i think i will go with a new cat. i also have to usual exhaust manifold leak/crack. so im just going to redo the whole thing at once!! not fun!! but if any one has a tip for a decent manifold but not to expensive that would be great!!

thanks again!!
Brookg is offline   Reply With Quote
Unread 07-10-2010, 05:39 AM   #11
Rammer500
Registered User
1999 TJ Wrangler 
 
Join Date: Jul 2009
Location: Avonmore,PA
Posts: 464
Quote:
Originally Posted by viperbluelx View Post
I don't agree with removing the cat, but there is so much misinformation in this thread I thought I'd reply.

The rear 02 sensor does nothing besides monitor catalytic converter function. The rear 02(the one you're trying to fool to keep the check engine light off) does not at all effect air fuel or engine performance, EVER. For that matter you could yank the cat, unplug the rear 02 and drive it with the check engine light on and you're still not going to see a performance decrease.
That's not how it works. Some makes, Yes, but for Jeep, no.
From the Factory Service Manual:

DOWNSTREAM HEATED OXYGEN SENSOR
The downstream heated oxygen sensor is located
near the outlet end of the catalytic convertor (Fig. 6).
The downstream heated oxygen sensor input is used
to detect catalytic convertor deterioration and provide
fuel adjustment information.
As the convertor deteriorates, the input from the
downstream sensor begins to match the upstream
sensor input except for a slight time delay. By comparing
the downstream heated oxygen sensor input
to the input from the upstream sensor, the PCM calculates
catalytic convertor efficiency.
When the catalytic converter efficiency drops below
emission standards, the PCM stores a diagnostic
trouble code and illuminates the Malfunction Indicator
(MIL) (or Check Engine) lamp. For more information,
refer to Group 25, Emission Control Systems.
The downstream sensor input is also used to adjust
the upstream O2S goal voltage. This allows a better
control of the exhaust gases as the catalytic convertor
ages.The upstream and downstream sensors may look
exactly alike, but are not interchangeable.
__________________
99 TJ 4.0 5 Speed Sport, 2.5" Rough Country Lift, 1.25 Body Lift, 1" MML, SYE and CV shaft,JKS Quicker Disconnects, 33x10.50 BFG Mud Terrains,4.56 gears, Super35 w/ Ected Locker, Warn 8274 and some other stuff.
2014 Rubicon Stock
Rammer500 is offline   Reply With Quote
Unread 07-10-2010, 05:47 AM   #12
Dryseals
Registered User
2000 TJ Wrangler 
 
Join Date: Apr 2010
Location: Texas
Posts: 628
Quote:
Originally Posted by Rammer500 View Post
That's not how it works. Some makes, Yes, but for Jeep, no.
From the Factory Service Manual:

DOWNSTREAM HEATED OXYGEN SENSOR
The downstream heated oxygen sensor is located
near the outlet end of the catalytic convertor (Fig. 6).
The downstream heated oxygen sensor input is used
to detect catalytic convertor deterioration and provide
fuel adjustment information.
As the convertor deteriorates, the input from the
downstream sensor begins to match the upstream
sensor input except for a slight time delay. By comparing
the downstream heated oxygen sensor input
to the input from the upstream sensor, the PCM calculates
catalytic convertor efficiency.
When the catalytic converter efficiency drops below
emission standards, the PCM stores a diagnostic
trouble code and illuminates the Malfunction Indicator
(MIL) (or Check Engine) lamp. For more information,
refer to Group 25, Emission Control Systems.
The downstream sensor input is also used to adjust
the upstream O2S goal voltage. This allows a better
control of the exhaust gases as the catalytic convertor
ages.The upstream and downstream sensors may look
exactly alike, but are not interchangeable.
Hey! Don't confuse facts with folklore. The down stream O2 does nothing, the UAW said it had to be there so some one could have a job installing it.
Dryseals is offline   Reply With Quote
Unread 10-17-2012, 01:33 AM   #13
dankscstchevy
Registered User
1996 ZJ 
 
Join Date: Oct 2012
Location: lake elsinore, ca
Posts: 117
don't do it....... I baught my Jeep for penny's because some kid got his parents jeep cut the cat out installed a fancy magnaflow muffler and it threw insufficient cat code plus wouldn't pass visual inspection which is needed to pass smog... installed new cat and now purrs like a Kitty $180 for a CA only cat from Napa auto
dankscstchevy is offline   Reply With Quote
Unread 10-17-2012, 06:01 AM   #14
c69ss396
Just me...
 
c69ss396's Avatar
2001 TJ Wrangler 
 
Join Date: Jan 2011
Location: Jacksonville, Fl
Posts: 687
Don't believe everything that you read, as stated before the rear o2 does nothing except monitor the converter. I have over 8yrs working for Chrysler. I have been to more schools then I care to remember. Removing the cat will not do anything to improve performance, the only thing it will do is piss off the tree huggers, I'm down for that but there are better ways to do that too.
c69ss396 is offline   Reply With Quote
Unread 10-23-2013, 11:10 AM   #15
frank1823
Registered User
 
Join Date: Oct 2013
Location: Sugar Land, Texas
Posts: 1
Riddle me this Batman

Quote:
Originally Posted by c69ss396 View Post
Don't believe everything that you read, as stated before the rear o2 does nothing except monitor the converter. I have over 8yrs working for Chrysler. I have been to more schools then I care to remember. Removing the cat will not do anything to improve performance, the only thing it will do is piss off the tree huggers, I'm down for that but there are better ways to do that too.
I realize this is an old post, but I ran across it and just had a comment. I am not a Chrysler tech, but used to be in Chrysler/Jeep parts for many years and a Chrysler/Jeep service advisor for for many as well. Riddle me this Batman. The cat creates resistance in the exhaust airflow does it not? How is it possible that removing the cat is not going to improve exhaust airflow and performance? It is simple physics. I understand the line about blah, blah, blah about now the O2 does not tell the PCM the correct info and the engine is not running correctly. I know someone very, very well that is running a TJ with hollowed out precats and main cat. It runs stronger than it ever did before that. Hes done it with other makes of cars with similar results in performance. Yeah, that will sure get the tree huggers upset out there because of the hole he is putting in the ozone layer. Just consider this - a volcanic eruption spews more ozone harmful stuff in a matter of seconds that we could produce in decades. I think we should be working on stopping volcanic eruptions instead.
frank1823 is offline   Reply With Quote
Reply

Tags
tj , wrangler , catalytic , converter , o2 , sensor , bypass , simulator
Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.