Catalytic Converter

jeepmedic46 · **Posted:** Fri Feb 26, 2010 7:40 pm

My check engine light came on and its displaying the code that says I need new catalytic converters. The stealership wants 1500 dollars for the setup and I was told that I need to replace my o2 sensors at the same time. Total bill will be a little uner 2000 dollars. Is this about the right price? I went to a local auto parts store and he told me to go with the factory cats as the aftermarket ones send to set off codes.

tjkj2002 · **Posted:** Fri Feb 26, 2010 7:59 pm

jeepmedic46 wrote:

My check engine light came on and its displaying the code that says I need new catalytic converters. The stealership wants 1500 dollars for the setup and I was told that I need to replace my o2 sensors at the same time. Total bill will be a little uner 2000 dollars. Is this about the right price? I went to a local auto parts store and he told me to go with the factory cats as the aftermarket ones send to set off codes.

Yeah they would be correct,aftermarket cats tend to keep throwing the same codes you got right now.

What year and how many miles on your KJ?

jeepmedic46 · **Posted:** Fri Feb 26, 2010 8:01 pm

Its a 2004 with just under 120,000 miles.

tjkj2002 · **Posted:** Fri Feb 26, 2010 8:04 pm

jeepmedic46 wrote:

Its a 2004 with just under 120,000 miles.

Yeah so your well over the federal cat warranty of 8/80,000.

JeepinJarhead03 · **Posted:** Fri Feb 26, 2010 8:39 pm

when I had to price them for mine (3 cat exhaust, 2 small 1 main) the 2 small ones were cheep, the main was like 800 bucks

X3 on the aftermarket 'universal' cat's causing problems, they'll burn up the upstream cats too

Daksport · **Posted:** Sat Feb 27, 2010 10:16 am

Alright, I'm gonna need an for an explanation on this.

I've always been a fan of replacing the stock cat with a magnaflow cat on any other vehicle I've ever had and never had any issue so what is different about the Liberty???

I've never had any problems running aftermarket cats and they have always passed emissions with flying colours. The only difference I can see so far is that the Liberty has 3 cats whereas all my other vehicles have only had 1 cat.

JeepinJarhead03 · **Posted:** Sat Feb 27, 2010 3:07 pm

the 2 smaller cats have a tendancy of burning out due to too much, or not enough backpressure and then it'll start throwin codes and eating o2's

jeepmedic46 · **Posted:** Sat Feb 27, 2010 5:04 pm

Thats what the auto parts store told me. Now all I have to do is come up with the money. :JEEPIN:

Daksport · **Posted:** Sat Feb 27, 2010 6:32 pm

Interesting.

Is there any replacement options for the two pre-cats???

JeepinJarhead03 · **Posted:** Sat Feb 27, 2010 8:55 pm

if im not mistaken, the 2 precat's are around 100 bucks a piece OEM

Daksport · **Posted:** Sun Feb 28, 2010 11:28 am

Found my answer to the replacement pre cats. Magnaflow does offer replacement pre-cats as well as a full Y-Pipe w/ cats replacement:

http://www.autoanything.com/exhausts-mu ... 0423c27407

You can add a universal main cat onto that for ~$100 more.

I've checked over at rockauto.com as well and they sell Walker Catalytic parts. The d/s, p/s and main cat would cost ~$620 + shipping.

Personally speaking, I would opt for the magnaflow system and save some serious coin. With the savings, I would also get a hi-flow muffler and complete the package and get maximum benefit out of the exhaust. You could probably complete the whole package for about $1000.

Just my :2cents:

jeepmedic46 · **Posted:** Sun Feb 28, 2010 12:53 pm

I do like that price, Do I need to get the third cat and will it trip my codes? :JEEPIN:

Daksport · **Posted:** Sun Feb 28, 2010 1:02 pm

Yes you will need the 3rd cat.

I don't believe it would trip codes as all 3 cats would be functioning properly.

jeepmedic46 · **Posted:** Sun Feb 28, 2010 1:19 pm

Thank you, That will save me a lot of money. jeep needs to be inspected in May and needs the Exhaust, also need to replace my front fender after some moron cut me off. :JEEPIN:

Daksport · **Posted:** Mon Mar 01, 2010 1:10 am

I've been doing some poking around and I'm hoping that someone can confirm my findings for me.

From what I have found, the 2003 KJ's had a 3 cat exhaust system. The 2004 and later KJ's only had a 2 cat exhaust system. This is based on the following:

http://colorado4wheel.com/manuals/Jeep/ ... _FICHE.pdf
http://colorado4wheel.com/manuals/Jeep/ ... _FICHE.pdf

Can someone confirm that my findings are correct???

If so, then jeepmedic46 won't be in need of the main cat. He will only require the Y Pipe assembly.

JeepinJarhead03 · **Posted:** Mon Mar 01, 2010 3:26 am

03's with a 45RFE seemed to have came with the 3 cat system, 42RLE 03's seemed to have came with the 2 cat system

now, the iffy tricky deal

the 3 cat system, i honestly don't feel that the high-flow universal magnaflow type MAIN cat would burn up the 2 smaller cats because mine was ran without a cat there at all for quite some time as the place i got it from stole the cat before i bought it

it threw no codes, the 2 smaller cats were fine, however running it that way after you know about it, is just as illegal as it was take a sawzaw to the pipe and steal the cat and put a pipe back in place

however, on the 3 cat system, the main cat is more of a resonator than it is a cat, it does very little for the exhaust quality, and it is blind - blind meaning there's on sensor after it

on the 2 cat system is where the verified problems seem to have occurred (correct me if you personally know of a high flow burning out the 2 small cats on a 3 cat system) but, we seem to know for sure that the high flow 2nd large cat will burn up the oem first cat

replace them both with highflow universals and it should be fine??maybe??

also, be careful with the universals, as some are not legal for use on california emission vehicles and some aren't legal for use at all

don't blame me for that one, blame CARB lol

liquidxit2 · **Posted:** Mon Mar 01, 2010 1:04 pm

I never had any issues with magnaflow highflow cats, but I will say I hate their mufflers. If you have 3 cats designed to be together you should be fine. Those y pipes are tempting especially after adding the roof rack.

JeepinJarhead03 · **Posted:** Mon Mar 01, 2010 2:38 pm

friend of mine has a shop, and has had car after car after car with 2 and some 3 cat systems come back time and after time due to codes and the other cats gettin fried

so i think you're right on the designed together part

replace all, or go OEM

liquidxit2 · **Posted:** Mon Mar 01, 2010 4:40 pm

JeepinJarhead03 wrote:

friend of mine has a shop, and has had car after car after car with 2 and some 3 cat systems come back time and after time due to codes and the other cats gettin fried

so i think you're right on the designed together part

replace all, or go OEM

Agreed. Those multicat systems are a PITA.

JeepinJarhead03 · **Posted:** Mon Mar 01, 2010 5:06 pm

Yessirrr!

back when i was still workin in a shop, i ran a few on the sniffer, one that had 2 mini cats and the pipe cut off - was fixin to put an exhaust on it for a guy

and one with a 2 cat with the high flows

and resniffed the 3 cat a few weeks later, didn't see hardly any difference at all with the larger cat on and they were roughly equal, and way cleaner than the requirements

then NC went to different machines that required recert and i never recerted

so my initial feeling, as long as the 2 minis are working correctly, and it's properly tuned with all the emissions equiptment working properly including the computer and o2 sensors, the 3rd cat never really does much at all, as long as it's a blind cat

the 3rd cat off a non-blind cat will throw codes and run rich as **** due to o2 sensor readings which can be fixed with o2 emulators, but.. not legal, what-so-ever

in ours, there's very little gain to be had by removing cats even with emulators, simply a pain in the buttocks if you have to replace a large cat

Catalytic Converter

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