Symptoms of bad cat converter?

2000 Mazda Protege ES with 151k miles on it

What are the symptoms of a bad catalytic converter?

The CEL keeps coming on but the error code is "vague"
and sounds to me like it could be the catcon or even O2
sensors!

Money is tight for me and I can't replace BOTH the O2
sensors and catcon at this time and want to replace
only what is bad.

There are two O2 sensors total cost abt $200...and of
course the catcon is abt $225.... not including labor
for all this.

My CEL keeps coming on and my gas mileage is poor.

I always thought a catcon was good for life of the car.
Is 151k too soon for catcon to be bad?

If you were gonna choose between the catcon or the two
O2 sensors.... which one would you have replaced given
my symptoms above?

wrote:
> 2000 Mazda Protege ES with 151k miles on it
>
> What are the symptoms of a bad catalytic converter?
>
> The CEL keeps coming on but the error code is "vague"
> and sounds to me like it could be the catcon or even O2
> sensors!
>
> Money is tight for me and I can't replace BOTH the O2
> sensors and catcon at this time and want to replace
> only what is bad.
>
> There are two O2 sensors total cost abt $200...and of
> course the catcon is abt $225.... not including labor
> for all this.
>
> My CEL keeps coming on and my gas mileage is poor.
>
> I always thought a catcon was good for life of the car.
> Is 151k too soon for catcon to be bad?
>
> If you were gonna choose between the catcon or the two
> O2 sensors.... which one would you have replaced given
> my symptoms above?

Well what is the code? or codes?
If you have more than one O2 sensor they will each have codes associated
with them if they fail.

To check the converter you could have the exhaust tested with an
analyzer. The O2 sensor is easy to test as well. You just need to
measure the voltage coming off of it and compare it to the specifications.

150K is well past what many of the manufacturers consider the "life" of
a vehicle.

--
Steve W.

"Steve W." > wrote:

>Well what is the code? or codes?

Not sure exact code as the mechanic did the scan.

I will call and ask them for exact number

> wrote: (2000 Mazda Protege ES 151k miles)

My CEL keeps coming on and my gas mileage is poor.
The error code is "vague" and sounds like it could be
the catcon or the O2 sensors.
Isn't the catcon supposed to be good for life of the car?
Would you replace the catcon or the two O2 sensors
given my symptoms above?
_______________________________________________

I would not replace either based on the sole symptom
you cited (poor gas mileage). Please give more info:

How poor is the gas mileage?

What is the actual error code you read?

What is vague about that code?

Rodan.

Poor gas mileage will destroy a catalytic converter. It could be caused by
the O2 sensor but you need the codes to determine that. Guessing at parts to
replace is expensive and futile. The car needs to be diagnosed with an OBDII
tester and then the correct parts can be determined. If you have been
driving for a while with poor mileage the CAT is probably gone but the only
symptom that will cause is pollution. It will have no effect on the
drivability of the car


> wrote in message
...
> 2000 Mazda Protege ES with 151k miles on it
>
> What are the symptoms of a bad catalytic converter?
>
> The CEL keeps coming on but the error code is "vague"
> and sounds to me like it could be the catcon or even O2
> sensors!
>
> Money is tight for me and I can't replace BOTH the O2
> sensors and catcon at this time and want to replace
> only what is bad.
>
> There are two O2 sensors total cost abt $200...and of
> course the catcon is abt $225.... not including labor
> for all this.
>
> My CEL keeps coming on and my gas mileage is poor.
>
> I always thought a catcon was good for life of the car.
> Is 151k too soon for catcon to be bad?
>
> If you were gonna choose between the catcon or the two
> O2 sensors.... which one would you have replaced given
> my symptoms above?

> wrote in message
...
> 2000 Mazda Protege ES with 151k miles on it
>
> What are the symptoms of a bad catalytic converter?
>
> The CEL keeps coming on but the error code is "vague"
> and sounds to me like it could be the catcon or even O2
> sensors!

Does it use a male or female voice when it tells you?

: )

What ARE the codes you're getting?

wrote:

> 2000 Mazda Protege ES with 151k miles on it
>
> What are the symptoms of a bad catalytic converter?

It's as cold as the exhaust pipe going into it? Can you borrow one of
those infrared thermometers to take its temperature?

> The CEL keeps coming on but the error code is "vague"
> and sounds to me like it could be the catcon or even O2 sensors!

I've found that mechanics vary a lot in their diagnostic skills, and
some don't seem to know how to interpret the OBDII codes, except
literally. The O2 sensor before the cat should give out about 0.6V DC
(measure only with a high impedance meter, like a digital voltage
meter) or 1Vpeak-peak on a oscilloscope, while the O2 sensor after the
cat should put out only a feeble signal if the cat is working, or a
strong signal if the cat is bad.

www.PDFtown.com has factory manuals for 1996 and 2002 Proteges, as
well as lots of other factory manuals for various makes of vehicles.
A factory manual will cover the fuel/emissions systems in a lot more
detail than any Chilton or Haynes manual will and in terms that are
easier to understand. The next best reference is a Mitchell manual
from a library, preferrably the paper version.

> If you were gonna choose between the catcon or the two
> O2 sensors.... which one would you have replaced given
> my symptoms above?

If I was tight on money, I wouldn't "have" them replaced but would
replace them myself, but only after proper diagnosis proved that they
were bad. The only thing I might "have" done by someone else would be
a detailed diagnosis (i.e., specifies everything that has to be done
and everything that has to be replaced) by a _good_ mechanic who knows
all about Mazda fuel/emissions and doesn't make hit-or-miss guesses.

Have you tried the FAQs and forums at places like MazdaForum.com and
MsProtege.com ?

In article >,
> wrote:
>2000 Mazda Protege ES with 151k miles on it
>
>What are the symptoms of a bad catalytic converter?
>
>The CEL keeps coming on but the error code is "vague"
>and sounds to me like it could be the catcon or even O2
>sensors!
>
>Money is tight for me and I can't replace BOTH the O2
>sensors and catcon at this time and want to replace
>only what is bad.
>
>There are two O2 sensors total cost abt $200...and of
>course the catcon is abt $225.... not including labor
>for all this.
>
>My CEL keeps coming on and my gas mileage is poor.
>
>I always thought a catcon was good for life of the car.
>Is 151k too soon for catcon to be bad?
>
>If you were gonna choose between the catcon or the two
>O2 sensors.... which one would you have replaced given
>my symptoms above?

But we have no idea what your symptoms are. You don't even tell us
what the actual error code is, and you have made no measurements of
any sort. What is the error code and what does the exhaust look and
smell like?
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

can't a muffler shop put some sort of pressure tester prior to the
catalytic convertor to see if there is excessive back pressure? That
would make the most sense. If they can't, then here is an opportunity
to make millions.

> wrote in message
...
> can't a muffler shop put some sort of pressure tester prior to the
> catalytic convertor to see if there is excessive back pressure? That
> would make the most sense. If they can't, then here is an opportunity
> to make millions.

Of course, that can be done...but I dont think it is usually done.

It is too easy to throw parts at the problem, and minimize diagnosis.

Sound cynical?

Had a charge problem with FIL's pickup a short while ago. They replaced the
alternator and brought it home. CEL came on.

I took it back.

They replaced the ECM.. Engine light came on and truck ran rough.

Took it back..

They replaced the oxygen sensors and brought it home. CEL is still on.

$604 later, this piece of GM ****, serviced at the local GM dealership,
is still shining the CEL.

At least, here in Texas we have one of the strongest Deceptive Trade
Practices
Acts in the nation. Im ****ed.