Various Topics on Subaru

.... ..urtrig..

runcyclexcski@gmail.com wrote:
>
> My '02 Impreza Outback got 121,000 miles, and my local subaru dealer
> has got a Cat converter check engine code reading.t. They quoted me
> $850 to replace the Cat ($650 part + $200 labor).

Hi,

A couple of thoughts after "interesting" experiences getting past
California smog tests:

Cats do go bad, but it's far more likely you've got an O2 sensor
failure. Not sure how many sensors you have, but it sounds like you have
one in the exhaust stream of the cat. My smog guy tells me this one
rarely goes out (if it's throwing a code, it's obviously working), but
can tell you one of two things:

First is the cat's dead. Think big bucks as you've heard. He says
"emissions wise" the cheap replacements do as well as OEM. HOWEVER, I've
seen nothing but grief down the road w/ OEMs, both on my cars and
others. It starts w/ the installation problems: they usually don't just
bolt in like OEM. From there you could have heating problems--the guys
I've seen put 'em in weren't always the brightest when it came to
figuring out WHY the factory spent all that money for heat shielding! I
was lucky--my carpet only got "warm." An acquaintance wasn't quite so
lucky--he burnt the carpet in his truck pretty badly. So... if you don't
care about driving the car much in the future, go "cheap" but if you
want to return the car to "constant" service, suck it up and buy OEM.
Doing so saved me money in the long run.

The other thing a cat code could mean is the upstream O2 sensor(s) is a
goner. The mixture going to the cat is too rich for it to handle
properly. Nothing wrong w/ the cat itself, it's just overloaded
(especially problematic as the systems age.) Not such big bucks to fix.

My current smog guy says the upstream O2 sensors are generally good for
about 60k miles (though some last longer, none I've had made it past
100k), and cats for about 150k. So you're due for O2 sensors "again"
according to him, but still have another 30k on your cat. Generally!

Were this my car, I'd start by replacing O2 sensors, resetting all
codes, and starting over.

Now, for "urban legend" and such: the entire emissions system HAS to be
up to operating temps to work right. Again, as the car ages, this
becomes more important. One of my smog guys always told me to drive the
car 5-10 miles to get things hot. Another always blocked the throttle
for a full minute to two minutes to make sure the cat in particular was
"hot." My current guy says both approaches should be combined.

He also suggests any time you're "not quite sure" to have a "pre-test"
done. This gives all the readings w/o upsetting the DMV computer w/ a
"failure" reading that stays on the vehicle record (ever do a CarFax
inquiry and see the "failures" on some cars?) He charges me half the
regular price of a test for the pre-test, and applies the charge to the
real test if I'm ok. In other words, if I fail, I pay half price, go fix
whatever it takes, then come back and try again. If it p***es the
pre-test, he'll run it again "for real" and only charge me the one full
fee.

You might ask your guy about doing this since you've already had
problems.

Good luck!

Rick

..cha..

Well it wouldnt. They dont do those here, depends on the year car i think.
They just hook mine up and look for codes and do a gas cap pressure test.



<runcyclexcski@gmail.com> wrote in message
news:2bf99e69-b277-4c0a-8030-d81e8fd45269@p39g2000prm.googlegroups.com...
> On Jul 3, 8:32 am, "Michael Prosek" <upssu...@earthlink.net> wrote:
>> You can try installing a spacer on your rear o2 sensor. I have a catless
>> exhaust on my 03 WRX. The spacer pulls the o2 sensor out of the direct
>> flow
>> of the exhaust , no CEL and gets threw emissions. Costs about $2. You get
>> 2
>> spark plug spacers available at any autoparts store. I can dig up the
>> part
>> number if you need it. You will need to drill out the opening some on the
>> spacers too.
>
> I can see how that can clear the check engine light but how would that
> affect the smog check readings?
>
>
>> <runcyclexc...@gmail.com> wrote in message
>>
>> news:ac0a945c-0bf6-4ebe-8b76-bdf724fe3bf5@i36g2000prf.googlegroups.com...
>>
>> > My '02 Impreza Outback got 121,000 miles, and my local subaru dealer
>> > has got a Cat converter check engine code reading.t. They quoted me
>> > $850 to replace the Cat ($650 part + $200 labor).
>>
>> > All I need is to p*** the California smogs. I am not driving the car
>> > much anymore anyway (gas prices), just keep it in the driveway for an
>> > occasional camping trip (still cheaper than renting... provided no
>> > major repair costs) so giving out $800 just to register the thing just
>> > does not sound right.
>>
>> > Goggling produced a $150 (???) "Catco" converter. Does anyone have
>> > experience with this beast? Can I bolt it on myself to keep the
>> > smoggers happy?
>>
>> > Also, I am not sure if the sensor in the car gives a yes/no kind of
>> > answer, or actually produces a real number. Meaning that if I knew
>> > that the reading was on the borderline, can I make the car barely p***
>> > somehow (heard some urban legends on driving on a highway before the
>> > test).
>

..diy..

On Jul 2, 1:53*am, runcyclexc...@gmail.com wrote:
> My '02 Impreza Outback got 121,000 miles, and my local subaru dealer
> has got a Cat converter check engine code reading.t. They quoted me
> $850 to replace the Cat ($650 part + $200 labor).
>
> All I need is to p*** the California smogs. I am not driving the car
> much anymore anyway (gas prices), just keep it in the driveway for an
> occasional camping trip (still cheaper than renting... provided no
> major repair costs) so giving out $800 just to register the thing just
> does not sound right.
>
> Goggling produced a $150 (???) "Catco" converter. Does anyone have
> experience with this beast? Can I bolt it on myself to keep the
> smoggers happy?
>
> Also, I am not sure if the sensor in the car gives a yes/no kind of
> answer, or actually produces a real number. Meaning that if I knew
> that the reading was on the borderline, can I make the car barely p***
> somehow (heard some urban legends on driving on a highway before the
> test).

Hey there,

I had a similar problem with my 2001 Impreza Outback and I subscribed
to ALLDATAdiy.com and it has been very useful. I am handy and like to
do things myself and this subscription gives me diagnosis, repair,
TBSs, recalls and labor times.

Check it out - I copied the link below for you.

http://traffic.alldatadiy.com/cgi-bi...0-o4010-c66365

Andy Deil

..ncyclexcs.. ..ail.c..

On Jul 2, 1:53 am, runcyclexc...@gmail.com wrote:
> My '02 Impreza Outback got 121,000 miles, and my local subaru dealer
> has got a Cat converter check engine code reading.t. They quoted me
> $850 to replace the Cat ($650 part + $200 labor).
>
> All I need is to p*** the California smogs. I am not driving the car
> much anymore anyway (gas prices), just keep it in the driveway for an
> occasional camping trip (still cheaper than renting... provided no
> major repair costs) so giving out $800 just to register the thing just
> does not sound right.
>
> Goggling produced a $150 (???) "Catco" converter. Does anyone have
> experience with this beast? Can I bolt it on myself to keep the
> smoggers happy?
>
> Also, I am not sure if the sensor in the car gives a yes/no kind of
> answer, or actually produces a real number. Meaning that if I knew
> that the reading was on the borderline, can I make the car barely p***
> somehow (heard some urban legends on driving on a highway before the
> test).

Hi all,

I bugged you guys ~2 months ago about a cat converter error code on a
'02 Impreza, and I got some very good suggestions from you.

The problem was an check engine light on (code P0420 - "cat converter
below thershold efficiency"), and my dealer was trying to convince me
to spend $800 on a new CAT. I can't p*** the CA smog test with the
test engine light on.

Well, my registration is due in 2 weeks and I just took the car for a
smog test (the dealer protested, saying why bother - well, since the
retests are free, why not).

It p***ed the smog test ***easily***. At idle the numbers were:
14.6% CO2, 0.1% O2, 17 ppm HC, 0.03% CO, not anywhere close to the max
allowed numbers.

So I runs back to the dealer and ask them just to replace the front O2
sensor. But they *insist* on replacing the cat converter, saying that
if the system says it fails, it fails.

So the question is - how can the cat converter be faulty if the
emissions are fine? Or do the emission people and the cat converter
sensor measure different things?

I can insist on replacing just the O2 sensor ($250 as opposed to $800)
though, but at this point I don't know if I can trust them at all -
unless I misunderstand something.

..ncyclexcs.. ..ail.c..

On Jul 5, 11:44 am, Rick Courtright <rcourtri...@iname.com> wrote:
> runcyclexc...@gmail.com wrote:
>
> > My '02 Impreza Outback got 121,000 miles, and my local subaru dealer
> > has got a Cat converter check engine code reading.t. They quoted me
> > $850 to replace the Cat ($650 part + $200 labor).
>
> Hi,
>
> A couple of thoughts after "interesting" experiences getting past
> California smog tests:
>
> Cats do go bad, but it's far more likely you've got an O2 sensor
> failure. Not sure how many sensors you have, but it sounds like you have
> one in the exhaust stream of the cat. My smog guy tells me this one
> rarely goes out (if it's throwing a code, it's obviously working), but
> can tell you one of two things:
>
> First is the cat's dead. Think big bucks as you've heard. He says
> "emissions wise" the cheap replacements do as well as OEM. HOWEVER, I've
> seen nothing but grief down the road w/ OEMs, both on my cars and
> others. It starts w/ the installation problems: they usually don't just
> bolt in like OEM. From there you could have heating problems--the guys
> I've seen put 'em in weren't always the brightest when it came to
> figuring out WHY the factory spent all that money for heat shielding! I
> was lucky--my carpet only got "warm." An acquaintance wasn't quite so
> lucky--he burnt the carpet in his truck pretty badly. So... if you don't
> care about driving the car much in the future, go "cheap" but if you
> want to return the car to "constant" service, suck it up and buy OEM.
> Doing so saved me money in the long run.
>
> The other thing a cat code could mean is the upstream O2 sensor(s) is a
> goner. The mixture going to the cat is too rich for it to handle
> properly. Nothing wrong w/ the cat itself, it's just overloaded
> (especially problematic as the systems age.) Not such big bucks to fix.
>
> My current smog guy says the upstream O2 sensors are generally good for
> about 60k miles (though some last longer, none I've had made it past
> 100k), and cats for about 150k. So you're due for O2 sensors "again"
> according to him, but still have another 30k on your cat. Generally!
>
> Were this my car, I'd start by replacing O2 sensors, resetting all
> codes, and starting over.
>
> Now, for "urban legend" and such: the entire emissions system HAS to be
> up to operating temps to work right. Again, as the car ages, this
> becomes more important. One of my smog guys always told me to drive the
> car 5-10 miles to get things hot. Another always blocked the throttle
> for a full minute to two minutes to make sure the cat in particular was
> "hot." My current guy says both approaches should be combined.
>
> He also suggests any time you're "not quite sure" to have a "pre-test"
> done. This gives all the readings w/o upsetting the DMV computer w/ a
> "failure" reading that stays on the vehicle record (ever do a CarFax
> inquiry and see the "failures" on some cars?) He charges me half the
> regular price of a test for the pre-test, and applies the charge to the
> real test if I'm ok. In other words, if I fail, I pay half price, go fix
> whatever it takes, then come back and try again. If it p***es the
> pre-test, he'll run it again "for real" and only charge me the one full
> fee.
>
> You might ask your guy about doing this since you've already had
> problems.
>
> Good luck!
>
> Rick

I got a second opinion from another mechanic and he suggested
replacing the upstream sensor. But how can an upstream sensor throw an
error about a downstream component (i.e. cat)? Weird. Funny how you
can spend $250 to replace a sensor, and still don't know for sure if
it's going to fix the check engine light on.

.... .. ..c.. ..x..

runcyclexcski@gmail.com wrote:
> On Jul 2, 1:53 am, runcyclexc...@gmail.com wrote:
>
>>My '02 Impreza Outback got 121,000 miles, and my local subaru dealer
>>has got a Cat converter check engine code reading.t. They quoted me
>>$850 to replace the Cat ($650 part + $200 labor).
>>
>>All I need is to p*** the California smogs. I am not driving the car
>>much anymore anyway (gas prices), just keep it in the driveway for an
>>occasional camping trip (still cheaper than renting... provided no
>>major repair costs) so giving out $800 just to register the thing just
>>does not sound right.
>>
>>Goggling produced a $150 (???) "Catco" converter. Does anyone have
>>experience with this beast? Can I bolt it on myself to keep the
>>smoggers happy?
>>
>>Also, I am not sure if the sensor in the car gives a yes/no kind of
>>answer, or actually produces a real number. Meaning that if I knew
>>that the reading was on the borderline, can I make the car barely p***
>>somehow (heard some urban legends on driving on a highway before the
>>test).
>
>
> Hi all,
>
> I bugged you guys ~2 months ago about a cat converter error code on a
> '02 Impreza, and I got some very good suggestions from you.
>
> The problem was an check engine light on (code P0420 - "cat converter
> below thershold efficiency"), and my dealer was trying to convince me
> to spend $800 on a new CAT. I can't p*** the CA smog test with the
> test engine light on.
>
> Well, my registration is due in 2 weeks and I just took the car for a
> smog test (the dealer protested, saying why bother - well, since the
> retests are free, why not).
>
> It p***ed the smog test ***easily***. At idle the numbers were:
> 14.6% CO2, 0.1% O2, 17 ppm HC, 0.03% CO, not anywhere close to the max
> allowed numbers.
>
> So I runs back to the dealer and ask them just to replace the front O2
> sensor. But they *insist* on replacing the cat converter, saying that
> if the system says it fails, it fails.
>
> So the question is - how can the cat converter be faulty if the
> emissions are fine? Or do the emission people and the cat converter
> sensor measure different things?
>
> I can insist on replacing just the O2 sensor ($250 as opposed to $800)
> though, but at this point I don't know if I can trust them at all -
> unless I misunderstand something.

There is no direct way for the OBDII to measure cat performance other
than comparing the upstream and downstream sensor values with ideal
numbers in memory.(basically) So, for most cars, it would be like trying
to measure one old component using 2 other old components. But a GOOD
shop should be able to perform tests on the sensors that would show slow
switching or a failed heater circuit, etc. They should also be able to
do a tailpipe emissions test. Basically, your dealer is either corrupt
or incompetent (hard to see a 3rd option here).

This not say its impossible to have more than one bad component. Or,
indeed, replace one now, and need a second component replaced in a few
days/weeks w'ever.

try reading a couple of articles here;
http://www.troublecodes.net/articles/

OBDII..simply explained
Cat. Eff. Failures


Carl


--
to reply, change ( .not) to ( .net)

..ncyclexcs.. ..ail.c..

On Aug 25, 5:57 pm, Carl 1 Lucky Texan <alcky...@swbell.not> wrote:
> runcyclexc...@gmail.com wrote:
> > On Jul 2, 1:53 am, runcyclexc...@gmail.com wrote:
>
> >>My '02 Impreza Outback got 121,000 miles, and my local subaru dealer
> >>has got a Cat converter check engine code reading.t. They quoted me
> >>$850 to replace the Cat ($650 part + $200 labor).
>
> >>All I need is to p*** the California smogs. I am not driving the car
> >>much anymore anyway (gas prices), just keep it in the driveway for an
> >>occasional camping trip (still cheaper than renting... provided no
> >>major repair costs) so giving out $800 just to register the thing just
> >>does not sound right.
>
> >>Goggling produced a $150 (???) "Catco" converter. Does anyone have
> >>experience with this beast? Can I bolt it on myself to keep the
> >>smoggers happy?
>
> >>Also, I am not sure if the sensor in the car gives a yes/no kind of
> >>answer, or actually produces a real number. Meaning that if I knew
> >>that the reading was on the borderline, can I make the car barely p***
> >>somehow (heard some urban legends on driving on a highway before the
> >>test).
>
> > Hi all,
>
> > I bugged you guys ~2 months ago about a cat converter error code on a
> > '02 Impreza, and I got some very good suggestions from you.
>
> > The problem was an check engine light on (code P0420 - "cat converter
> > below thershold efficiency"), and my dealer was trying to convince me
> > to spend $800 on a new CAT. I can't p*** the CA smog test with the
> > test engine light on.
>
> > Well, my registration is due in 2 weeks and I just took the car for a
> > smog test (the dealer protested, saying why bother - well, since the
> > retests are free, why not).
>
> > It p***ed the smog test ***easily***. At idle the numbers were:
> > 14.6% CO2, 0.1% O2, 17 ppm HC, 0.03% CO, not anywhere close to the max
> > allowed numbers.
>
> > So I runs back to the dealer and ask them just to replace the front O2
> > sensor. But they *insist* on replacing the cat converter, saying that
> > if the system says it fails, it fails.
>
> > So the question is - how can the cat converter be faulty if the
> > emissions are fine? Or do the emission people and the cat converter
> > sensor measure different things?
>
> > I can insist on replacing just the O2 sensor ($250 as opposed to $800)
> > though, but at this point I don't know if I can trust them at all -
> > unless I misunderstand something.
>
> There is no direct way for the OBDII to measure cat performance other
> than comparing the upstream and downstream sensor values with ideal
> numbers in memory.(basically) So, for most cars, it would be like trying
> to measure one old component using 2 other old components. But a GOOD
> shop should be able to perform tests on the sensors that would show slow
> switching or a failed heater circuit, etc. They should also be able to
> do a tailpipe emissions test. Basically, your dealer is either corrupt
> or incompetent (hard to see a 3rd option here).
>
> This not say its impossible to have more than one bad component. Or,
> indeed, replace one now, and need a second component replaced in a few
> days/weeks w'ever.
>
> try reading a couple of articles here;http://www.troublecodes.net/articles/
>
> OBDII..simply explained
> Cat. Eff. Failures
>
> Carl
>

Carl - so, would a good emission test argue against a bad converter?

My other mechanic says that the upstream sensor fails statistically
more frequently because it experiences more stress (the sensor
generates voltage, right). I kind of buy that.

.... ..

runcyclexcski@gmail.com writes:

> The problem was an check engine light on (code P0420 - "cat converter
> below thershold efficiency"), and my dealer was trying to convince me
> to spend $800 on a new CAT. I can't p*** the CA smog test with the
> test engine light on.


Since your original post, my 01 has thrown this very same code. And
supposedly, I have a brand new aftermarket cat that's under a year
old.

FWIW, I reset the code with the scanner I own ($100 at Wal Mart made
by Innova.) The code didn't come back for another month or so,
which gave me 3 weeks of no-CEL driving during which the counters were
also clear (i.e. would p*** emissions). I think it took about a week
of driving to build up enough engine time to reset/p*** the rest of
the stuff that makes for a happy emissions odbii check. It isn't
considered "clean" right after you reset everything.

Anyway, if you are blowing clean emissions, and it does just look like
a sensor issue, you can have a buddy with a code scanner reset your
code, wait a week and have them recheck to make sure all the
counters/such have gotten to their happy place, then immediately go in
and have those emission checked, and you may make it another year.

Just one option anyway.


--
Todd H.
2001 Legacy Outback Wagon, 2.5L H-4
Chicago, Illinois USA

.... .. ..c.. ..x..

runcyclexcski@gmail.com wrote:
> On Aug 25, 5:57 pm, Carl 1 Lucky Texan <alcky...@swbell.not> wrote:
>
>>runcyclexc...@gmail.com wrote:
>>
>>>On Jul 2, 1:53 am, runcyclexc...@gmail.com wrote:
>>
>>>>My '02 Impreza Outback got 121,000 miles, and my local subaru dealer
>>>>has got a Cat converter check engine code reading.t. They quoted me
>>>>$850 to replace the Cat ($650 part + $200 labor).
>>
>>>>All I need is to p*** the California smogs. I am not driving the car
>>>>much anymore anyway (gas prices), just keep it in the driveway for an
>>>>occasional camping trip (still cheaper than renting... provided no
>>>>major repair costs) so giving out $800 just to register the thing just
>>>>does not sound right.
>>
>>>>Goggling produced a $150 (???) "Catco" converter. Does anyone have
>>>>experience with this beast? Can I bolt it on myself to keep the
>>>>smoggers happy?
>>
>>>>Also, I am not sure if the sensor in the car gives a yes/no kind of
>>>>answer, or actually produces a real number. Meaning that if I knew
>>>>that the reading was on the borderline, can I make the car barely p***
>>>>somehow (heard some urban legends on driving on a highway before the
>>>>test).
>>
>>>Hi all,
>>
>>>I bugged you guys ~2 months ago about a cat converter error code on a
>>>'02 Impreza, and I got some very good suggestions from you.
>>
>>>The problem was an check engine light on (code P0420 - "cat converter
>>>below thershold efficiency"), and my dealer was trying to convince me
>>>to spend $800 on a new CAT. I can't p*** the CA smog test with the
>>>test engine light on.
>>
>>>Well, my registration is due in 2 weeks and I just took the car for a
>>>smog test (the dealer protested, saying why bother - well, since the
>>>retests are free, why not).
>>
>>>It p***ed the smog test ***easily***. At idle the numbers were:
>>>14.6% CO2, 0.1% O2, 17 ppm HC, 0.03% CO, not anywhere close to the max
>>>allowed numbers.
>>
>>>So I runs back to the dealer and ask them just to replace the front O2
>>>sensor. But they *insist* on replacing the cat converter, saying that
>>>if the system says it fails, it fails.
>>
>>>So the question is - how can the cat converter be faulty if the
>>>emissions are fine? Or do the emission people and the cat converter
>>>sensor measure different things?
>>
>>>I can insist on replacing just the O2 sensor ($250 as opposed to $800)
>>>though, but at this point I don't know if I can trust them at all -
>>>unless I misunderstand something.
>>
>>There is no direct way for the OBDII to measure cat performance other
>>than comparing the upstream and downstream sensor values with ideal
>>numbers in memory.(basically) So, for most cars, it would be like trying
>>to measure one old component using 2 other old components. But a GOOD
>>shop should be able to perform tests on the sensors that would show slow
>>switching or a failed heater circuit, etc. They should also be able to
>>do a tailpipe emissions test. Basically, your dealer is either corrupt
>>or incompetent (hard to see a 3rd option here).
>>
>>This not say its impossible to have more than one bad component. Or,
>>indeed, replace one now, and need a second component replaced in a few
>>days/weeks w'ever.
>>
>>try reading a couple of articles here;http://www.troublecodes.net/articles/
>>
>>OBDII..simply explained
>>Cat. Eff. Failures
>>
>>Carl
>>
>
>
> Carl - so, would a good emission test argue against a bad converter?
>
> My other mechanic says that the upstream sensor fails statistically
> more frequently because it experiences more stress (the sensor
> generates voltage, right). I kind of buy that.

I have read MANY reports of upstream sensors failing WAY before the
downstream unit. There are probably 2-3 reasons for this in various
combination(heat, more corrosive g***es,etc.). Not impossible to have a
bad converter or bad downstream converter - just difficult for the
upstream sensor to last much over 80,000 miles or so. Could some last to
130K? probably. Some also fail at 60K or less. Especially if they have
been exposed to coolant from a leaking HG or other stresses. And it is
often a 'slow' failure. Sometimes the code can be cleared and may not
return for weeks.

There probably are some rare mechanical ways a Cat converter could be
partially clogged but still p*** an emissions test - dunno - but the car
would probably have driveability isues at high speeds or under load.


Carl


--
to reply, change ( .not) to ( .net)

.... .. ..c.. ..x..

runcyclexcski@gmail.com wrote:

> On Aug 25, 5:57 pm, Carl 1 Lucky Texan <alcky...@swbell.not> wrote:
>
>>runcyclexc...@gmail.com wrote:
>>
>>>On Jul 2, 1:53 am, runcyclexc...@gmail.com wrote:
>>
>>>>My '02 Impreza Outback got 121,000 miles, and my local subaru dealer
>>>>has got a Cat converter check engine code reading.t. They quoted me
>>>>$850 to replace the Cat ($650 part + $200 labor).
>>
>>>>All I need is to p*** the California smogs. I am not driving the car
>>>>much anymore anyway (gas prices), just keep it in the driveway for an
>>>>occasional camping trip (still cheaper than renting... provided no
>>>>major repair costs) so giving out $800 just to register the thing just
>>>>does not sound right.
>>
>>>>Goggling produced a $150 (???) "Catco" converter. Does anyone have
>>>>experience with this beast? Can I bolt it on myself to keep the
>>>>smoggers happy?
>>
>>>>Also, I am not sure if the sensor in the car gives a yes/no kind of
>>>>answer, or actually produces a real number. Meaning that if I knew
>>>>that the reading was on the borderline, can I make the car barely p***
>>>>somehow (heard some urban legends on driving on a highway before the
>>>>test).
>>
>>>Hi all,
>>
>>>I bugged you guys ~2 months ago about a cat converter error code on a
>>>'02 Impreza, and I got some very good suggestions from you.
>>
>>>The problem was an check engine light on (code P0420 - "cat converter
>>>below thershold efficiency"), and my dealer was trying to convince me
>>>to spend $800 on a new CAT. I can't p*** the CA smog test with the
>>>test engine light on.
>>
>>>Well, my registration is due in 2 weeks and I just took the car for a
>>>smog test (the dealer protested, saying why bother - well, since the
>>>retests are free, why not).
>>
>>>It p***ed the smog test ***easily***. At idle the numbers were:
>>>14.6% CO2, 0.1% O2, 17 ppm HC, 0.03% CO, not anywhere close to the max
>>>allowed numbers.
>>
>>>So I runs back to the dealer and ask them just to replace the front O2
>>>sensor. But they *insist* on replacing the cat converter, saying that
>>>if the system says it fails, it fails.
>>
>>>So the question is - how can the cat converter be faulty if the
>>>emissions are fine? Or do the emission people and the cat converter
>>>sensor measure different things?
>>
>>>I can insist on replacing just the O2 sensor ($250 as opposed to $800)
>>>though, but at this point I don't know if I can trust them at all -
>>>unless I misunderstand something.
>>
>>There is no direct way for the OBDII to measure cat performance other
>>than comparing the upstream and downstream sensor values with ideal
>>numbers in memory.(basically) So, for most cars, it would be like trying
>>to measure one old component using 2 other old components. But a GOOD
>>shop should be able to perform tests on the sensors that would show slow
>>switching or a failed heater circuit, etc. They should also be able to
>>do a tailpipe emissions test. Basically, your dealer is either corrupt
>>or incompetent (hard to see a 3rd option here).
>>
>>This not say its impossible to have more than one bad component. Or,
>>indeed, replace one now, and need a second component replaced in a few
>>days/weeks w'ever.
>>
>>try reading a couple of articles here;http://www.troublecodes.net/articles/
>>
>>OBDII..simply explained
>>Cat. Eff. Failures
>>
>>Carl
>>
>
>
> Carl - so, would a good emission test argue against a bad converter?
>
> My other mechanic says that the upstream sensor fails statistically
> more frequently because it experiences more stress (the sensor
> generates voltage, right). I kind of buy that.

Also, read here;
http://www.troublecodes.net/articles/catfailure/


Carl


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