"What if" I found a 2000 JGC for sale, but the Seller told me that he
had "modified" the catalytic converter, by welding in a piece of straight
pipe in its place ?


I am not a mechanic, but I seem to recall that there are one or two oxygen
sensors before and after the catalytic converter that feed information to
the car's computer, adjusting the carb, etc etc. Are there steps that can
be taken to get around this potential problem ?

If this would be a significant problem, should I either avoid buying the
car, or just plan to have a new catalytic converter installed ?


What are the pros and cons ?

Thanks for any tips or advice !!


James

If you really want to buy it, tell the seller if he doesn't sell it to you
at your named price, with a new cat installed per factory specs you'll take
the VIN and report it to the DMV and EPA, and he'll be fined through the
nose.

:-)

Seriously, though, if you live in a state that requires smog inspection
that's an automatic fail. And if he did that, you have to wonder what else
this genius has done to it. Did he tell you why he installed a "test pipe?"
If you are going to buy it, you should really have him pay to install the
cat, as it's illegal to operate it without one.

As far as the O2 sensors go, you're right, it senses the exhaust gas mix and
adjusts the fuel delivery parameters (no carb on this one, it's fuel
injected) and the lack of a cat would give false readings and probably screw
up your fuel economy.

"James" <jnipperxxx (AT) nospamfdn (DOT) com> wrote

The modificatioin is illegal in most states. You could be saddled with a
repair bill of around $500 to correct the illegal conditiion. I would run,
not walk, to the nearest exit.





"James" <jnipperxxx (AT) nospamfdn (DOT) com> wrote

"James" <jnipperxxx (AT) nospamfdn (DOT) com> wrote

Call your aftermarket exhaust shops and price a cat installed. Whatever the
price is, negotiate the difference with the seller off of his asking price.
If you think the Jeep is what you want. It needs to be on there so it'll
pass inspection. The O2 sensors are precat, so the engine computer doesn't
really know it's back there. It is there to insure the unwanted pollutive
gases are more completely burned before exiting the exhaust. Most cats made
in the last ten years or so aren't as restrictive as the early ones, but
people still take them out, thinking they are "freeing up more horsepower".

Spdloader

"Spdloader" <askforit (AT) nospam (DOT) triad.rr.com> wrote

On a 2000 model, the odds are very good that there is an after-CAT O2 Sensor
to detect and report an ineffeciency with the CAT's performance.

I agree with you, the OP needs to get the CAT installed before he makes the
purchase, but I think the CAT should be installed entirely on the seller's
dime. I would not buy a vehicle with the CAT missing because this tells me
that the seller may have cut off other important parts that I'm going to be
wanting.

As a general rule of thumb, there is no benefit to removing the CAT from
modern cars and trucks. There is an arguable benefit to removing them from
older vehicles, but unless the CAT is destroyed internally (clogged), it
will not have an adverse affect on airflow through the exhaust system. The
CAT does more good than harm, so it should remain unaltered.

To be sure, there are people that engage in street racing, or other forms of
racing, and they may benefit by having the CAT altered or removed, but a
Jeep Cherokee is not among the class of vehicles that will be raced in a
fashion that would make it beneficial to alter or remove the CAT. And, the
Cherokee was raced, then it would be a poor candidate to add to my
collection of cars and trucks.

My suggestion stands, run do not walk to the nearest exit and do not look
back.

To tell a secret, I replaced my cat with straight pipe when I upgraded
my exhaust - the cat was dead, and I didn't feel like buying a new one.
I wish I had just gotten a new cat, though, aside from the fact that I
feel bad emitting more pollutants than usual, it's incredibly loud.
The cat acts as a resonator before your muffler, which smooths out
engine noise a lot more than one would suspect - you definitely notice
it when it's gone, though.
I love the rumble my 4banger has at idle, but at high speeds, it's
little better than a ricer. I shouldn't say that, it sounds like I have
no muffler at all. One of these days, when I have the time/money/tools
to put a cat in, it'll get put back in.

Jeff Strickland wrote:

Oh yeah, where I live inspection only takes place upon registration of
the vehicle - after that, unless a cop catches you, everything pretty
much becomes fair game.

The Merg wrote:

It is strange that he removed the CAT in the first place. I believe he
wrongly assumed he would get more HP. Having said that, the biggest concern
I would have is not with the EPA. My biggest concern would be if your state
requires an emission test to register the vehicle. If so, your screwed
because it will never pass without CAT. If you live in a sate that has no
emission tests, then go ahead and buy the Jeep. You have nothing to worry
about.


"Jeff Strickland" <crwlr (AT) verizon (DOT) net> wrote

There is likely to be an 02 sensor after the cat, even my '97 has an 02
sensor mounted into the cat at the tail-end of it. That 02 sensor's job
is to check for proper 02 sensor function so I'm surprised there's no
Check Engine light.

--
Jerry Bransford
PP-ASEL N6TAY
See the Geezer Jeep at
http://members.cox.net/jerrypb/

Thanks for all the input, guys !!


James