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01 jeep wrangler 4.0 auto - Gutting the cat

Rich1

I looked--I listened--I changed
Joined
Dec 10, 2006
Messages
2,986
Location
northwest
I don't have emissions here, my motor doesn't smoke...

Can I gut the cat?

Is there a 02 sensor ?

*trying to get a better flow thru and small gains in HP
:corn:
 
I don't have emissions here, my motor doesn't smoke...

Can I gut the cat?

Is there a 02 sensor ?

*trying to get a better flow thru and small gains in HP
:corn:

I will trip the computer and make it run different.I know summit catalog sells dumby o2 sensors and that will make it run normal again.
 
I don't have emissions here, my motor doesn't smoke...

Can I gut the cat? Can you? Yes. Is it illegal? Yes.

Is there a 02 sensor ? Yes and without the cat, you'll set codes.

*trying to get a better flow thru and small gains in HP
:corn:

Just gutting the cat on a stock system will give you little to no gain. Don't bother.
 
There's no reason to gut the cat for more flow/ HP; won't happen if the rig's stock; The only thing it'll do is make it louder, and trip the "check Engine" light w/ a PO420 " Catalyst Efficiency " code; The OBD system uses the post-cat O2 only as a way of monitoring the catalyst's efficiency, and won't have any effect on performance....leave it alone, or if you must, buy an aftermarket "Hi-Flow" cat, although the gains you probably won't notice w/ a stock engine....and it STILL might trip a PO420 code....depends on how sensitive the catalyst monitoring strategy is in your rig's PCM....
 
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ok... Figured there was a 02 sensor somewheres...

So I might as well just leave it... Eventually I'll get the complete system intake header flow thru cat muffler

Just seems like the cat, is restricting / clogged. Most likely the owner before me, never got the rpm's over 2g's. :haha:
 
sometimes the cat can be "Saved"; Go and run the livin' dog$#!t out of it (high RPMs for long periods-10-20 seconds at a time) cruise around normal for a few minutes to let it cool some, then repeat. Might help clean it out some(burn off any carbon build-up)...no guarantees, though....Hard to Diag a cat issue over the WEB!!!:redneck: :fawkdancesmiley:
 
ok... Figured there was a 02 sensor somewheres...

So I might as well just leave it... Eventually I'll get the complete system intake header flow thru cat muffler

Just seems like the cat, is restricting / clogged. Most likely the owner before me, never got the rpm's over 2g's. :haha:

Get a new exhaust, bump up the size. I'm running 2.5" exhaust with a cat. The inline 6's need the cat to run properly. They need the back pressure.If you cat is clogged you will reach a certain speed and wont be able to go any faster, like 50mph or less.
 
ok... Figured there was a 02 sensor somewheres...

So I might as well just leave it... Eventually I'll get the complete system intake header flow thru cat muffler

Just seems like the cat, is restricting / clogged. Most likely the owner before me, never got the rpm's over 2g's. :haha:

If you feel the cat is clogged pull the front o2 sensor and drive it to see if the power is better. More than likely it is not the problem.

More likely the fuel pump is weak, or the fuel filter (built into the regulator on top of the tank) is restricted causing low fuel flow.

If you have more than 80k, drop the tank and replace it, before it takes the pump out.
 
If you feel the cat is clogged pull the front o2 sensor and drive it to see if the power is better. More than likely it is not the problem.

More likely the fuel pump is weak, or the fuel filter (built into the regulator on top of the tank) is restricted causing low fuel flow.

If you have more than 80k, drop the tank and replace it, before it takes the pump out.

x2 on pulling the o2 sensor or most exhaust shops have back pressure gauges to test for plugged cats. I dont know what other shops charge for it but it is a free service at mine.

"Warning" following is epa illegal and can involve heavy fines if caught (not likely). Federal emission laws apply even to non-tested vehicles.
If you decide to hollow the cat out, run a pipe through it to keep from getting a resonance from the open chamber. You will also need a rear o2 simulator or have the comp reflashed to work without the cat.
 
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If you feel the cat is clogged pull the front o2 sensor and drive it to see if the power is better. More than likely it is not the problem.

More likely the fuel pump is weak, or the fuel filter (built into the regulator on top of the tank) is restricted causing low fuel flow.

If you have more than 80k, drop the tank and replace it, before it takes the pump out.

Where the hell did you come up with that? Just pulled that out of your ass did ya?

If his fuel pump was weak it wouldn't run worth a **** even at idle. From my experience, fuel pumps either work or dont. Some will work for a minute or two after they cool down, but when they get warm they shut off.= Bad pump.


Rich what size tires are you running and is it on stock gears?? Oversized tires with stock gears will feel like a weak motor or lack of power. Get the proper gears and you'll have power again.
 
I don't have emissions here, my motor doesn't smoke...

Can I gut the cat?

Is there a 02 sensor ?

*trying to get a better flow thru and small gains in HP
:corn:

Why dont you just sell it and buy one that doesnt have a cat!!!!Times up on ownership anyway....way up ........two weeks was along time ago!!!!!:haha: :haha:
 
Where the hell did you come up with that? Just pulled that out of your ass did ya?

If his fuel pump was weak it wouldn't run worth a **** even at idle. From my experience, fuel pumps either work or dont. Some will work for a minute or two after they cool down, but when they get warm they shut off.= Bad pump.


Rich what size tires are you running and is it on stock gears?? Oversized tires with stock gears will feel like a weak motor or lack of power. Get the proper gears and you'll have power again.

While most fuel pump failures are complete, once in a while they fail to produce enough pressure, open a service manual and it will tell you how to test for a failing internal pressure release valve. I have done 2 cherokee pumps in the last few months that failed this test. Real mind fawk to diagnose when you don't do alot of driveability in your day to day
 
Why dont you just sell it and buy one that doesnt have a cat!!!!Times up on ownership anyway....way up ........two weeks was along time ago!!!!!:haha: :haha:



:fawkdancesmiley:

Awe........ loosing money on me this time huh....

:fawkdancesmiley:

Let's see, :corn: Just how long have "I" actually had this rig? :eeek:

============

It's going to be a keeper Brian, Do i miss the last Zuk? yeah... but, i made a choice and it had all the right reasons behind it. Don't be a Jeep hater... :D

*(when you coming to get that D44 to weld up for me?) :awesomework:

Thats really the only thing stopping me from running trails. at least the weak d35 would be out and in w/ the d44 welded. :;

===========================================

AS for the cat, alot of good answers. it makes no difference unless it's constantly filling with mud and drying it in there. i don't do mud, i'm sick of changing bearings / etc from the mud abuse. been avoiding the deep water / mud for awhile now. my rig is running rich, and i'm sure a little old man previously owned it, and never ran it over 2000 rpms. :haha:

i have no problem letting it know i have a heavy right foot. :haha: maybe it's carbon build up from running rich. a few more high rpm start offs after it's been warmed up and it should BURN off the build up. fuel pumps are tricky little bastards, THERES NICE PRESSURE GUAGES that can be used. but joops pretty dead on. my rigs running great. under 80k and perfect, just thought about yanking the cat or gutting it. *seems like a little gain could be accomplished there. after a air header muffler was installed down the line.

but for now, that cat can remain. i'll just continue to heat it up really good and check out the fuel setting to make sure it's adjusted properly for running a little leaner. :D

thx, guys. :beer:
 
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Where the hell did you come up with that? Just pulled that out of your ass did ya?

If his fuel pump was weak it wouldn't run worth a **** even at idle. From my experience, fuel pumps either work or dont. Some will work for a minute or two after they cool down, but when they get warm they shut off.= Bad pump.


That was uncalled for and you need more experience in a shop. It is a very common problem on the wranglers. Fuel pressure drops off after warming up. Will idle fine but no power on hills.
 
That was uncalled for and you need more experience in a shop. It is a very common problem on the wranglers. Fuel pressure drops off after warming up. Will idle fine but no power on hills.

awe don't let the poop get ta ya...

on hills i'am fine, no drop in idle after warm ups. i think it just has alot to do with 3.07's and 32's - and the fact this jeep was babied by a non-redliner. She's doing a little better today, i've been giving her what she needs and i know is good for her. a good hard push here and there on her peddle and a stomping every now and then. this 4.0 is begging for MOD's to let it BREATH.

and EXHALE too. :haha:
 

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