whos running no cat

[Goatman]

NotMatt, mine is an '88, and obviously not OBDII. My comments were just about it running fine without the cat, and the noise, and that his seemed to run fine before he dunked it, so likely the problem is the dunk.

Not getting into the discussion about the importance of the cat, except for a small comment. I haven't experienced bad running problems with OBDII vehicles that have bad cats, just that the cat has to be replaced to get the check engine light to go off. I run a shop, and we do smogs, in CA so I have some experience. No comment on the rest of the stuff, because I don't know much more than what I've already said.

NotMatt, your are 100% wrong

How to win friends and influence people.

 

[MudDawg]

The emissions thing depends on where you live in Florida...some counties or municipalities have testing.

AZ....come on down one of these days....I can take you places where you can get so stuck it takes a bulldozer to pull you out....can you say "Gator hole?"

OK....my MJ is fully hooked up....the XJ Heep has no cat...or any other emissions device beyond a pcv valve.

As for the modded trucks...any convenience store at 6 am looks like a monster truck show. (big and bad is the norm for a lot of construction workers in this area) and home construction is INSANE right now...44's abound...

 

[black93xj]

My 93 and my girlfriends 94 both do not have cats. It makes your exaust louder by far. We still have plenty of toqure (she can roast 31's) and she gets better gas mileage than I do with a larger tire. If your area doesn't reqire it and you don't have two o2 sensers I say remove it. Oh and someone asked how to put a o2 senser into a new pipe? Simple buy spark plug anti foulers and trim al little off and weld into the pipe. Spark plugs and o2 sensers have the same tread.

 

[stupidfast]

man do i hate electronic technology. the only electronics that should be on a truck are lights, ignition, and fuel injection. like my 87 mj. screw o2 sensors and abs and traction control and keyless entry and cruise control and automatic transmisions. all garbage. should have bought a renix

 

[aplatz]

I have a '96 and replaced all the OX Sensors, but the rear one in the cat had the cables ripped out from the drive shaft when the plastic bracket broke. Now I'm running it w/ the sensor in the cat, but no wires going to the sensor. It does not "limp" at all. Aside fro the CEL being on, you can't tell. I'm going to replace it and hopefully get some gas miledge back, but when I replace my old rattling cat and cracked manifold.

 

[KSXJ]

I run with no cat. I am trying to get whats called a MIL elininator to work for me. I think I need to take it back off and sauder the ends instead of crimping. But since the MIL isn't working I get the engine light, but autozone has a reader that you can checkout or use at the store that can read and clear the codes. So I do that once a month to make sure nothing else is wrong.

 

[tealcherokee]

the upsteam sensor puts out a sign wave from -1 to 1

downstream puts out a steady (but not constant) line from .05v-1.2v (usually), an open (0v) sets a MIL, to get rid of the MIL simply take the 5v in, and use a resistor to make it about .6v and hook it up to the sensor wire for the computer

 

[black93xj]

limp mode is short for limp home mode. The jeep will get bad gas mileage and not run as effcent. I do not think it is a good idea to know whats wrong and leave it that way.

 

[2001XJeep]

1. The second O2 sensor is just measuring catalyst efficiency, has no impact on air/fuel map. However, it will throw a trouble code if you do not have it hooked up or have gutted/removed the cat.

2. On large displacement V8's it is possible that a free flowing cat will make little difference in exhaust sound, but on small 4 & 6 cylinders it makes a dramatic difference. Very little, if any, performance enhancement on engines like the 4.0 I6, maybe +/-1%.

3. The cats do not "burn" exhaust gases, the exhaust gases are chemically transformed by passing through the catalyst.

4. Anyone that thinks taking the cat off is a good idea is either too young to know any better or too stupid, doesn't matter which. Test = take a vehicle with a functional cat and park it in a garage, take a second vehicle without a cat and park in another garage. Let each run about 30 seconds and then tell me which is cleaner (answer = you will be running out of the garage with the vehicle with no cat because the fumes will be so noxious! The cat equipped vehicle's garage will not be bad at all). Now expand that concept to our environment and multiple by a couple billion vehicles, I think I've made my point. Cat = good, no cat = bad.

 

[XgeekstarX]

The emissions thing depends on where you live in Florida...some counties or municipalities have testing.

AZ....come on down one of these days....I can take you places where you can get so stuck it takes a bulldozer to pull you out....can you say "Gator hole?"

OK....my MJ is fully hooked up....the XJ Heep has no cat...or any other emissions device beyond a pcv valve.

As for the modded trucks...any convenience store at 6 am looks like a monster truck show. (big and bad is the norm for a lot of construction workers in this area) and home construction is INSANE right now...44's abound...

i love florida so much. i think one in four vehicles around here is a lifted truck with atleast 35's.

 

[87manche]

The catalytic convertor plays no part in the way the exhaust sounds. From what I understand, there is no emmisions in Florida, so your not breaking any laws. But it does no harm, and in fact does good....so why not have one on there?

I believe that the catalytic converter is required by Federal law. It is unlawful to run a vehicle on public roads without a cat.

 

[rstarch345]

From what I understand, there is no emmisions in Florida, so your not breaking any laws. But it does no harm, and in fact does good....so why not have one on there?

I believe that the catalytic converter is required by Federal law. It is unlawful to run a vehicle on public roads without a cat.

FYI

“The installation of non-complying converters by a named party will be considered a violation of section 203(a)(3) of the Clean Air Act, and the violator may be subject to a civil penalty of up to $25,000 for each improper installation.”



The text of the act also implies the removal.

 

[Goatman]

You guys need to get real. Who cares about the legality of having or not having a cat.....if there are no inspections to check it.

Tell me you don't exagerate on your taxes, and tell me you never drive over the speed limit. Give me a break.

 

[Wezil]

You can buy a O2 sensor eliminators but they usually come in pairs, so you would have an extra. Having the check engine light on is no good on a 96 It will retard timing and defuel the engine, get it off some how. I dont get how it was never on before, But some 96 XJ's still didnt have rear O2's I worked for Jeep 96-02 and I remember getting the wrong cat a few times and having to weld in a plug.

 

[AZ XJ]

i love florida so much. i think one in four vehicles around here is a lifted truck with atleast 35's.

I'd say that the ratio is the same here, but with the majority of those trucks being 1/2 ton 2wd chevy's on 40's with 22" rims and wranglers that look like they drove through 4 wheel parts and the whole store stuck to them, but have never seen dirt.... Arizona is the new California.

 

[sjx40250]

OK I would like to make an observation of noise with and without a CAT.

I think it does make a difference and at the same time does not. Here is my experience.
I put a new high flow CAT and flowmaster on my 97 GC with the 4.0L. Huge difference in sound. I bought the longer (21") muffler 'cause I thought it would be quiter than a shorter one. It also is SS.

So I thought great! I need a new muffler on my 92 XJ. I bought another flowmaster but not SS and shorter (14") at nearly half the price. Didn't change the CAT 'cause it passed emissions test and didn't rattle. Sound is almost the same as with the stock muffler.

Conclusion for me is that the sound will vary depending on which CAT you have. I looked through both before installation and the stock one looked far more restrictive than the high flow.

 

[outlander]

I can't believe you guy's admit to having no cat.....don't you know they're watching everthing we say on here.....oh no I have to go....someone's at the door.....
shhhhhh...be quiet! I'm not here....

 

[vetteboy]

When I flooded my XJ, the water backed up far enough down the tailpipe to get the O2 sensor wet. This ruined it and made it run like crap until I replaced it.

I ran my '94 with no cat for about a year, then put one back on for emissions testing and it felt like I just got a nice performance upgrade.

 

[emr1101]

96 4.0ho im running a open cone filter intake.i dont want a cat lol

you should run a cat anyway, just get highflow. if you dont have on a shit load of hydrocarbons get realeased into the air. At least make an attempt to keep our sport alive...

 

[WB9YZU]

There should be a difference in sound without a Catalytic Converter as the exhaust travels though a honey combed medium to reach the muffler, though I'm not sure it would be a positive improvement. That's personal taste, I like a quiet exhaust with a bit of low resonance when you gun it. None of that raspy noise I hear with those ricer mufflers, or resonance in the cabin.

Catalytic Convertors are mandated by the Federal under the Clean Air Act. Someone actually posted up the section earlier. I am old enough to remember the "good old days", when TEL was in fuel, air quality in town was less than it is now, and Lake Erie would actually burn occasionally (no joke). Somethings you just have to do because they make sense to do. Deleting your Cat is not one of them IMO.

I hate to say this, but we have been around this merry-go-round once before and it was decided that only allows posts about LEGAL modifications. So, where is the Moderator in all of this? Oh, that's right, Goatman's admitted to being a criminal too. What's that about the Fox guarding the Henhouse?