Tom and Nelson, thanks for your speedy replies.

The gentleman at AutoZone tried looking for additional codes, but that's the
only one he got. The car is 6 years old, which is not exactly late model,
but I follow you on that one. It's got 99K miles on it. I ran in the mid
30's per gallon couple weeks back. Now it runs below 20. My understanding is
that cold air causes more gas to be burned due to more oxygen coming in
because of compression in cold weather conditions. The loss in gas economy
is usually 10% which is about 3-4miles per gallon, and I've lost 15 or so.
That's not normal.

If someone has any other suggestions, please speak up.

Thanks!

--Viktor

"w_tom" <w_tom1@hotmail.com> wrote in message
news:40281356.BF019CC2@hotmail.com...
> P0420 is typically associated with a Three Way Catalytic
> Converter failure or with some type of exhaust leak. First,
> was that the only error code? IOW did they also forget to
> look for other error codes?
>
> A late model vehicle should not be suffering such failures.
> IOW reasons for such failures should also be addressed. How
> was gas mileage before these failures were happening? Engine
> problem that was dumping too much gasoline into the exhaust
> system would then degrade the converter. After all, what does
> a converter do? Burn the gasoline that the engine did not.
> For example, if gas mileage has always been low (ie low 20s
> MPG), then that problem may be why a converter failed.
>
> This is why you have a good dealer. Service mechanics will
> have enough experience with these rare failures as to quickly
> identify the problem AND locate the reason why that failure
> occurred. Because the Autozone man could not tell you this
> simple information up front, then assume he is not good enough
> to perform any service.
>
> Assume there is something else wrong since a catalytic
> converter failure alone just should not occur. Something else
> should have contributed to that failure. Too much gasoline
> not burned in the engine is bad for converters.
>
> electricked wrote:
> > I posted earlier with some questions regarding the check enging
> > light that came on few days ago. I put about 5 gallons of gas on
> > my last stop and it drove about 90 miles which is terrible. Less
> > than 20 miles a gallon. Terrible! Anyway, today I went to AutoZone
> > to get the free scan code check and it turned up P0420. Does
> > anyone know what this code means? The guy at AutoZone said it
> > might be the O2 sensor. I'm thinking it's either the O2
> > sensor or the catalytic converter since the car has been running
> > rich for the past week, and especially noticable in the last
> > couple of days. The check engine light was reseted today when he
> > tested it, and it hasn't come on since then. After he checked it,
> > it's been running smooth. No hesitation, seems it's not running
> > rich anymore, but only time will tell. I'll keep observing for
> > the next few days and fix whatever needs to be fixed over the
> > weekend.
> >
> > Any and all help is welcome and strongly appreciated.

 

Tom and Nelson, thanks for your speedy replies.

The gentleman at AutoZone tried looking for additional codes, but that's the
only one he got. The car is 6 years old, which is not exactly late model,
but I follow you on that one. It's got 99K miles on it. I ran in the mid
30's per gallon couple weeks back. Now it runs below 20. My understanding is
that cold air causes more gas to be burned due to more oxygen coming in
because of compression in cold weather conditions. The loss in gas economy
is usually 10% which is about 3-4miles per gallon, and I've lost 15 or so.
That's not normal.

If someone has any other suggestions, please speak up.

Thanks!

--Viktor

"w_tom" <w_tom1@hotmail.com> wrote in message
news:40281356.BF019CC2@hotmail.com...
> P0420 is typically associated with a Three Way Catalytic
> Converter failure or with some type of exhaust leak. First,
> was that the only error code? IOW did they also forget to
> look for other error codes?
>
> A late model vehicle should not be suffering such failures.
> IOW reasons for such failures should also be addressed. How
> was gas mileage before these failures were happening? Engine
> problem that was dumping too much gasoline into the exhaust
> system would then degrade the converter. After all, what does
> a converter do? Burn the gasoline that the engine did not.
> For example, if gas mileage has always been low (ie low 20s
> MPG), then that problem may be why a converter failed.
>
> This is why you have a good dealer. Service mechanics will
> have enough experience with these rare failures as to quickly
> identify the problem AND locate the reason why that failure
> occurred. Because the Autozone man could not tell you this
> simple information up front, then assume he is not good enough
> to perform any service.
>
> Assume there is something else wrong since a catalytic
> converter failure alone just should not occur. Something else
> should have contributed to that failure. Too much gasoline
> not burned in the engine is bad for converters.
>
> electricked wrote:
> > I posted earlier with some questions regarding the check enging
> > light that came on few days ago. I put about 5 gallons of gas on
> > my last stop and it drove about 90 miles which is terrible. Less
> > than 20 miles a gallon. Terrible! Anyway, today I went to AutoZone
> > to get the free scan code check and it turned up P0420. Does
> > anyone know what this code means? The guy at AutoZone said it
> > might be the O2 sensor. I'm thinking it's either the O2
> > sensor or the catalytic converter since the car has been running
> > rich for the past week, and especially noticable in the last
> > couple of days. The check engine light was reseted today when he
> > tested it, and it hasn't come on since then. After he checked it,
> > it's been running smooth. No hesitation, seems it's not running
> > rich anymore, but only time will tell. I'll keep observing for
> > the next few days and fix whatever needs to be fixed over the
> > weekend.
> >
> > Any and all help is welcome and strongly appreciated.

 

Yea, right on the money

However, don't dispair.... I personally think that your problem lies with
the cat, but thats just me.
HOWEVER, thats goodnews, regardless of what you may think. Only the 1st O2
sensor's data is used for the fuel/air mixture adjustement, the 2nd one only
monitors the efficiency of the catalytic converter. The dumb thing is, if
either of the sensors set a code, the engine might still be running in
open-loop mode (that is, lotsa gaz.... bad mileage).

It is techincally not dangerous (unless you're a green peace freak) to run
with a failing converter or a malfunctioning 2nd 02 sensor, as long as the
1st one (the one on top of the cat is working fine).

Here's the deal : there's a way to trick the ECU into thinking that the 2nd
02 sensor is working normally, even if it's busted or not even there. You
need to basically have the 02 output voltage in the right range (around 0.45
volts), and trick the heating circuit into thinking there's "something to
heat" - by shorting the terminal 3 and 4 of the connector with a resistor.
I'm a bit busy right now with school and whatnot, but this weekend when I
got some time, i'll design this thing for ya (its very basic, nothing but
resistors and capacitors) so you can try to plug it in, instead of the o2
sensor - for peace of mind Again, this would only work for the 2nd
sensor, the primary sensor is essential to good vehicle operation.



"electricked" <welcomehowcome@hotmail.com> wrote in message
news:a8ednV2TQv1E1LXd4p2dnA@comcast.com...
> Hello Yuri,
>
> Thanks for the informative reply.
>
> So basically, if the O2 sensor is damaged, even if the engine and the rest
> of the emission system is OK, it would still run rich because there's no
> appropriate feedback from the O2 sensor, am I getting this right? So if
the
> second O2 sensor is the problem, then replacing it will get the car back
to
> running normal, right?
>
> I pray to God it's not the catalytic converter because I'm a little low on
> the money right now. The second O2 sensor is $83 and the first one is $109
> at AutoZone. That's not too bad compared to a new catalytic converter, as
> you said running in the few hundreds' range.
>
> If anyone has more information they'd like to offer, I'm listening.
>
> Thanks!
>
> --Viktor
>
> "Yuri Nebogatov" <alexneb@videotron.ca> wrote in message
> news_WVb.59351$km5.1214477@wagner.videotron.net. ..
> > yea, it means the 02 sensor after the cat indicates that the mixture is
> too
> > fuel-rich.... either the 2nd heater 02 circuit is malfunctioning, or (as
> it
> > has been mentionned here), the catalytic converter is failing... in wich
> > case it sucks to be you cuz thats one expensive replacement.
> >
> > Get a real mechanic to check it out, if it's just the sensor, those
should
> > go for under 80$ (i'm talking about the 2nd O2 sensor, not the first one
> > located on top of the cat).
> > It takes about 2 mins to install one, but you need to warm up the engine
> > first a bit, since the catalytic converter expands when warm and makes
> > installation easier.
> >
> > If you need to replace the converter, thats anywhere from 170 - 400 $
> right
> > there, depending on the model ....
> >
> > These are, of course, prices for OEM or good brands ....
> > Bosch, etc...
> >
> > ANd you're right, if the code is lit - this indicates to the ECU that
> there
> > is a malfunciton with the censor, which in turn disables the real-time
> fuel
> > control... which is made to allow for optimum fuel /air ratio (something
> > that the 02 sensor monitors).
> >
> > In case of trouble, the car runs in open-loop mode, i.e. it reads data
> from
> > fuel injection tables... regardless of weither it makes for a healthy
> > fuel/air mixture... thus your car is "running rich".
> >
> > Hope any of this was helpful
> >
> > peace out
> >
> >
> >
> >
> >
> > "T. Nelson" <tnelson@nospam.com> wrote in message
> > news:tnelson-0902041644390001@pm1-broad-102.snlo.dialup.fix.net...
> > > In article <eaSdna0OT-5qlrXdRVn-hg@comcast.com>, "electricked"
> > > <welcomehowcome@hotmail.com> wrote:
> > >
> > > > Hello all,
> > > >
> > > > I posted earlier with some questions regarding the check enging
light
> > that
> > > > came on few days ago. I put about 5 gallons of gas on my last stop
and
> > it
> > > > drove about 90 miles which is terrible. Less than 20 miles a gallon.
> > > > Terrible! Anyway, today I went to AutoZone to get the free scan code
> > check
> > > > and it turned up P0420. Does anyone know what this code means? The
guy
> > at
> > > > AutoZone said it might be the O2 sensor. I'm thinking it's either
the
> O2
> > > > sensor or the catalytic converter since the car has been running
rich
> > for
> > > > the past week, and especially noticable in the last couple of days.
> The
> > > > check engine light was reseted today when he tested it, and it
hasn't
> > come
> > > > on since then. After he checked it, it's been running smooth. No
> > hesitation,
> > > > seems it's not running rich anymore, but only time will tell. I'll
> keep
> > > > observing for the next few days and fix whatever needs to be fixed
> over
> > the
> > > > weekend.
> > > >
> > > > Any and all help is welcome and strongly appreciated.
> > > >
> > > > Thank you!
> > > >
> > > > --Viktor
> > >
> > > According to my manual--PO420-- shows up as
> > > "Catalyst system efficiency below threshold."
> > > I don't know what this means--can anybody else interpret what this
> means?
> >
> >
>
>

 

Yea, right on the money

However, don't dispair.... I personally think that your problem lies with
the cat, but thats just me.
HOWEVER, thats goodnews, regardless of what you may think. Only the 1st O2
sensor's data is used for the fuel/air mixture adjustement, the 2nd one only
monitors the efficiency of the catalytic converter. The dumb thing is, if
either of the sensors set a code, the engine might still be running in
open-loop mode (that is, lotsa gaz.... bad mileage).

It is techincally not dangerous (unless you're a green peace freak) to run
with a failing converter or a malfunctioning 2nd 02 sensor, as long as the
1st one (the one on top of the cat is working fine).

Here's the deal : there's a way to trick the ECU into thinking that the 2nd
02 sensor is working normally, even if it's busted or not even there. You
need to basically have the 02 output voltage in the right range (around 0.45
volts), and trick the heating circuit into thinking there's "something to
heat" - by shorting the terminal 3 and 4 of the connector with a resistor.
I'm a bit busy right now with school and whatnot, but this weekend when I
got some time, i'll design this thing for ya (its very basic, nothing but
resistors and capacitors) so you can try to plug it in, instead of the o2
sensor - for peace of mind Again, this would only work for the 2nd
sensor, the primary sensor is essential to good vehicle operation.



"electricked" <welcomehowcome@hotmail.com> wrote in message
news:a8ednV2TQv1E1LXd4p2dnA@comcast.com...
> Hello Yuri,
>
> Thanks for the informative reply.
>
> So basically, if the O2 sensor is damaged, even if the engine and the rest
> of the emission system is OK, it would still run rich because there's no
> appropriate feedback from the O2 sensor, am I getting this right? So if
the
> second O2 sensor is the problem, then replacing it will get the car back
to
> running normal, right?
>
> I pray to God it's not the catalytic converter because I'm a little low on
> the money right now. The second O2 sensor is $83 and the first one is $109
> at AutoZone. That's not too bad compared to a new catalytic converter, as
> you said running in the few hundreds' range.
>
> If anyone has more information they'd like to offer, I'm listening.
>
> Thanks!
>
> --Viktor
>
> "Yuri Nebogatov" <alexneb@videotron.ca> wrote in message
> news_WVb.59351$km5.1214477@wagner.videotron.net. ..
> > yea, it means the 02 sensor after the cat indicates that the mixture is
> too
> > fuel-rich.... either the 2nd heater 02 circuit is malfunctioning, or (as
> it
> > has been mentionned here), the catalytic converter is failing... in wich
> > case it sucks to be you cuz thats one expensive replacement.
> >
> > Get a real mechanic to check it out, if it's just the sensor, those
should
> > go for under 80$ (i'm talking about the 2nd O2 sensor, not the first one
> > located on top of the cat).
> > It takes about 2 mins to install one, but you need to warm up the engine
> > first a bit, since the catalytic converter expands when warm and makes
> > installation easier.
> >
> > If you need to replace the converter, thats anywhere from 170 - 400 $
> right
> > there, depending on the model ....
> >
> > These are, of course, prices for OEM or good brands ....
> > Bosch, etc...
> >
> > ANd you're right, if the code is lit - this indicates to the ECU that
> there
> > is a malfunciton with the censor, which in turn disables the real-time
> fuel
> > control... which is made to allow for optimum fuel /air ratio (something
> > that the 02 sensor monitors).
> >
> > In case of trouble, the car runs in open-loop mode, i.e. it reads data
> from
> > fuel injection tables... regardless of weither it makes for a healthy
> > fuel/air mixture... thus your car is "running rich".
> >
> > Hope any of this was helpful
> >
> > peace out
> >
> >
> >
> >
> >
> > "T. Nelson" <tnelson@nospam.com> wrote in message
> > news:tnelson-0902041644390001@pm1-broad-102.snlo.dialup.fix.net...
> > > In article <eaSdna0OT-5qlrXdRVn-hg@comcast.com>, "electricked"
> > > <welcomehowcome@hotmail.com> wrote:
> > >
> > > > Hello all,
> > > >
> > > > I posted earlier with some questions regarding the check enging
light
> > that
> > > > came on few days ago. I put about 5 gallons of gas on my last stop
and
> > it
> > > > drove about 90 miles which is terrible. Less than 20 miles a gallon.
> > > > Terrible! Anyway, today I went to AutoZone to get the free scan code
> > check
> > > > and it turned up P0420. Does anyone know what this code means? The
guy
> > at
> > > > AutoZone said it might be the O2 sensor. I'm thinking it's either
the
> O2
> > > > sensor or the catalytic converter since the car has been running
rich
> > for
> > > > the past week, and especially noticable in the last couple of days.
> The
> > > > check engine light was reseted today when he tested it, and it
hasn't
> > come
> > > > on since then. After he checked it, it's been running smooth. No
> > hesitation,
> > > > seems it's not running rich anymore, but only time will tell. I'll
> keep
> > > > observing for the next few days and fix whatever needs to be fixed
> over
> > the
> > > > weekend.
> > > >
> > > > Any and all help is welcome and strongly appreciated.
> > > >
> > > > Thank you!
> > > >
> > > > --Viktor
> > >
> > > According to my manual--PO420-- shows up as
> > > "Catalyst system efficiency below threshold."
> > > I don't know what this means--can anybody else interpret what this
> means?
> >
> >
>
>

 

Yea, right on the money

However, don't dispair.... I personally think that your problem lies with
the cat, but thats just me.
HOWEVER, thats goodnews, regardless of what you may think. Only the 1st O2
sensor's data is used for the fuel/air mixture adjustement, the 2nd one only
monitors the efficiency of the catalytic converter. The dumb thing is, if
either of the sensors set a code, the engine might still be running in
open-loop mode (that is, lotsa gaz.... bad mileage).

It is techincally not dangerous (unless you're a green peace freak) to run
with a failing converter or a malfunctioning 2nd 02 sensor, as long as the
1st one (the one on top of the cat is working fine).

Here's the deal : there's a way to trick the ECU into thinking that the 2nd
02 sensor is working normally, even if it's busted or not even there. You
need to basically have the 02 output voltage in the right range (around 0.45
volts), and trick the heating circuit into thinking there's "something to
heat" - by shorting the terminal 3 and 4 of the connector with a resistor.
I'm a bit busy right now with school and whatnot, but this weekend when I
got some time, i'll design this thing for ya (its very basic, nothing but
resistors and capacitors) so you can try to plug it in, instead of the o2
sensor - for peace of mind Again, this would only work for the 2nd
sensor, the primary sensor is essential to good vehicle operation.



"electricked" <welcomehowcome@hotmail.com> wrote in message
news:a8ednV2TQv1E1LXd4p2dnA@comcast.com...
> Hello Yuri,
>
> Thanks for the informative reply.
>
> So basically, if the O2 sensor is damaged, even if the engine and the rest
> of the emission system is OK, it would still run rich because there's no
> appropriate feedback from the O2 sensor, am I getting this right? So if
the
> second O2 sensor is the problem, then replacing it will get the car back
to
> running normal, right?
>
> I pray to God it's not the catalytic converter because I'm a little low on
> the money right now. The second O2 sensor is $83 and the first one is $109
> at AutoZone. That's not too bad compared to a new catalytic converter, as
> you said running in the few hundreds' range.
>
> If anyone has more information they'd like to offer, I'm listening.
>
> Thanks!
>
> --Viktor
>
> "Yuri Nebogatov" <alexneb@videotron.ca> wrote in message
> news_WVb.59351$km5.1214477@wagner.videotron.net. ..
> > yea, it means the 02 sensor after the cat indicates that the mixture is
> too
> > fuel-rich.... either the 2nd heater 02 circuit is malfunctioning, or (as
> it
> > has been mentionned here), the catalytic converter is failing... in wich
> > case it sucks to be you cuz thats one expensive replacement.
> >
> > Get a real mechanic to check it out, if it's just the sensor, those
should
> > go for under 80$ (i'm talking about the 2nd O2 sensor, not the first one
> > located on top of the cat).
> > It takes about 2 mins to install one, but you need to warm up the engine
> > first a bit, since the catalytic converter expands when warm and makes
> > installation easier.
> >
> > If you need to replace the converter, thats anywhere from 170 - 400 $
> right
> > there, depending on the model ....
> >
> > These are, of course, prices for OEM or good brands ....
> > Bosch, etc...
> >
> > ANd you're right, if the code is lit - this indicates to the ECU that
> there
> > is a malfunciton with the censor, which in turn disables the real-time
> fuel
> > control... which is made to allow for optimum fuel /air ratio (something
> > that the 02 sensor monitors).
> >
> > In case of trouble, the car runs in open-loop mode, i.e. it reads data
> from
> > fuel injection tables... regardless of weither it makes for a healthy
> > fuel/air mixture... thus your car is "running rich".
> >
> > Hope any of this was helpful
> >
> > peace out
> >
> >
> >
> >
> >
> > "T. Nelson" <tnelson@nospam.com> wrote in message
> > news:tnelson-0902041644390001@pm1-broad-102.snlo.dialup.fix.net...
> > > In article <eaSdna0OT-5qlrXdRVn-hg@comcast.com>, "electricked"
> > > <welcomehowcome@hotmail.com> wrote:
> > >
> > > > Hello all,
> > > >
> > > > I posted earlier with some questions regarding the check enging
light
> > that
> > > > came on few days ago. I put about 5 gallons of gas on my last stop
and
> > it
> > > > drove about 90 miles which is terrible. Less than 20 miles a gallon.
> > > > Terrible! Anyway, today I went to AutoZone to get the free scan code
> > check
> > > > and it turned up P0420. Does anyone know what this code means? The
guy
> > at
> > > > AutoZone said it might be the O2 sensor. I'm thinking it's either
the
> O2
> > > > sensor or the catalytic converter since the car has been running
rich
> > for
> > > > the past week, and especially noticable in the last couple of days.
> The
> > > > check engine light was reseted today when he tested it, and it
hasn't
> > come
> > > > on since then. After he checked it, it's been running smooth. No
> > hesitation,
> > > > seems it's not running rich anymore, but only time will tell. I'll
> keep
> > > > observing for the next few days and fix whatever needs to be fixed
> over
> > the
> > > > weekend.
> > > >
> > > > Any and all help is welcome and strongly appreciated.
> > > >
> > > > Thank you!
> > > >
> > > > --Viktor
> > >
> > > According to my manual--PO420-- shows up as
> > > "Catalyst system efficiency below threshold."
> > > I don't know what this means--can anybody else interpret what this
> means?
> >
> >
>
>

 

Yea, right on the money

However, don't dispair.... I personally think that your problem lies with
the cat, but thats just me.
HOWEVER, thats goodnews, regardless of what you may think. Only the 1st O2
sensor's data is used for the fuel/air mixture adjustement, the 2nd one only
monitors the efficiency of the catalytic converter. The dumb thing is, if
either of the sensors set a code, the engine might still be running in
open-loop mode (that is, lotsa gaz.... bad mileage).

It is techincally not dangerous (unless you're a green peace freak) to run
with a failing converter or a malfunctioning 2nd 02 sensor, as long as the
1st one (the one on top of the cat is working fine).

Here's the deal : there's a way to trick the ECU into thinking that the 2nd
02 sensor is working normally, even if it's busted or not even there. You
need to basically have the 02 output voltage in the right range (around 0.45
volts), and trick the heating circuit into thinking there's "something to
heat" - by shorting the terminal 3 and 4 of the connector with a resistor.
I'm a bit busy right now with school and whatnot, but this weekend when I
got some time, i'll design this thing for ya (its very basic, nothing but
resistors and capacitors) so you can try to plug it in, instead of the o2
sensor - for peace of mind Again, this would only work for the 2nd
sensor, the primary sensor is essential to good vehicle operation.



"electricked" <welcomehowcome@hotmail.com> wrote in message
news:a8ednV2TQv1E1LXd4p2dnA@comcast.com...
> Hello Yuri,
>
> Thanks for the informative reply.
>
> So basically, if the O2 sensor is damaged, even if the engine and the rest
> of the emission system is OK, it would still run rich because there's no
> appropriate feedback from the O2 sensor, am I getting this right? So if
the
> second O2 sensor is the problem, then replacing it will get the car back
to
> running normal, right?
>
> I pray to God it's not the catalytic converter because I'm a little low on
> the money right now. The second O2 sensor is $83 and the first one is $109
> at AutoZone. That's not too bad compared to a new catalytic converter, as
> you said running in the few hundreds' range.
>
> If anyone has more information they'd like to offer, I'm listening.
>
> Thanks!
>
> --Viktor
>
> "Yuri Nebogatov" <alexneb@videotron.ca> wrote in message
> news_WVb.59351$km5.1214477@wagner.videotron.net. ..
> > yea, it means the 02 sensor after the cat indicates that the mixture is
> too
> > fuel-rich.... either the 2nd heater 02 circuit is malfunctioning, or (as
> it
> > has been mentionned here), the catalytic converter is failing... in wich
> > case it sucks to be you cuz thats one expensive replacement.
> >
> > Get a real mechanic to check it out, if it's just the sensor, those
should
> > go for under 80$ (i'm talking about the 2nd O2 sensor, not the first one
> > located on top of the cat).
> > It takes about 2 mins to install one, but you need to warm up the engine
> > first a bit, since the catalytic converter expands when warm and makes
> > installation easier.
> >
> > If you need to replace the converter, thats anywhere from 170 - 400 $
> right
> > there, depending on the model ....
> >
> > These are, of course, prices for OEM or good brands ....
> > Bosch, etc...
> >
> > ANd you're right, if the code is lit - this indicates to the ECU that
> there
> > is a malfunciton with the censor, which in turn disables the real-time
> fuel
> > control... which is made to allow for optimum fuel /air ratio (something
> > that the 02 sensor monitors).
> >
> > In case of trouble, the car runs in open-loop mode, i.e. it reads data
> from
> > fuel injection tables... regardless of weither it makes for a healthy
> > fuel/air mixture... thus your car is "running rich".
> >
> > Hope any of this was helpful
> >
> > peace out
> >
> >
> >
> >
> >
> > "T. Nelson" <tnelson@nospam.com> wrote in message
> > news:tnelson-0902041644390001@pm1-broad-102.snlo.dialup.fix.net...
> > > In article <eaSdna0OT-5qlrXdRVn-hg@comcast.com>, "electricked"
> > > <welcomehowcome@hotmail.com> wrote:
> > >
> > > > Hello all,
> > > >
> > > > I posted earlier with some questions regarding the check enging
light
> > that
> > > > came on few days ago. I put about 5 gallons of gas on my last stop
and
> > it
> > > > drove about 90 miles which is terrible. Less than 20 miles a gallon.
> > > > Terrible! Anyway, today I went to AutoZone to get the free scan code
> > check
> > > > and it turned up P0420. Does anyone know what this code means? The
guy
> > at
> > > > AutoZone said it might be the O2 sensor. I'm thinking it's either
the
> O2
> > > > sensor or the catalytic converter since the car has been running
rich
> > for
> > > > the past week, and especially noticable in the last couple of days.
> The
> > > > check engine light was reseted today when he tested it, and it
hasn't
> > come
> > > > on since then. After he checked it, it's been running smooth. No
> > hesitation,
> > > > seems it's not running rich anymore, but only time will tell. I'll
> keep
> > > > observing for the next few days and fix whatever needs to be fixed
> over
> > the
> > > > weekend.
> > > >
> > > > Any and all help is welcome and strongly appreciated.
> > > >
> > > > Thank you!
> > > >
> > > > --Viktor
> > >
> > > According to my manual--PO420-- shows up as
> > > "Catalyst system efficiency below threshold."
> > > I don't know what this means--can anybody else interpret what this
> means?
> >
> >
>
>

 

Hello Yuri,

Thanks for the informative reply.

So basically, if the O2 sensor is damaged, even if the engine and the rest
of the emission system is OK, it would still run rich because there's no
appropriate feedback from the O2 sensor, am I getting this right? So if the
second O2 sensor is the problem, then replacing it will get the car back to
running normal, right?

I pray to God it's not the catalytic converter because I'm a little low on
the money right now. The second O2 sensor is $83 and the first one is $109
at AutoZone. That's not too bad compared to a new catalytic converter, as
you said running in the few hundreds' range.

If anyone has more information they'd like to offer, I'm listening.

Thanks!

--Viktor

"Yuri Nebogatov" <alexneb@videotron.ca> wrote in message
news_WVb.59351$km5.1214477@wagner.videotron.net. ..
> yea, it means the 02 sensor after the cat indicates that the mixture is
too
> fuel-rich.... either the 2nd heater 02 circuit is malfunctioning, or (as
it
> has been mentionned here), the catalytic converter is failing... in wich
> case it sucks to be you cuz thats one expensive replacement.
>
> Get a real mechanic to check it out, if it's just the sensor, those should
> go for under 80$ (i'm talking about the 2nd O2 sensor, not the first one
> located on top of the cat).
> It takes about 2 mins to install one, but you need to warm up the engine
> first a bit, since the catalytic converter expands when warm and makes
> installation easier.
>
> If you need to replace the converter, thats anywhere from 170 - 400 $
right
> there, depending on the model ....
>
> These are, of course, prices for OEM or good brands ....
> Bosch, etc...
>
> ANd you're right, if the code is lit - this indicates to the ECU that
there
> is a malfunciton with the censor, which in turn disables the real-time
fuel
> control... which is made to allow for optimum fuel /air ratio (something
> that the 02 sensor monitors).
>
> In case of trouble, the car runs in open-loop mode, i.e. it reads data
from
> fuel injection tables... regardless of weither it makes for a healthy
> fuel/air mixture... thus your car is "running rich".
>
> Hope any of this was helpful
>
> peace out
>
>
>
>
>
> "T. Nelson" <tnelson@nospam.com> wrote in message
> news:tnelson-0902041644390001@pm1-broad-102.snlo.dialup.fix.net...
> > In article <eaSdna0OT-5qlrXdRVn-hg@comcast.com>, "electricked"
> > <welcomehowcome@hotmail.com> wrote:
> >
> > > Hello all,
> > >
> > > I posted earlier with some questions regarding the check enging light
> that
> > > came on few days ago. I put about 5 gallons of gas on my last stop and
> it
> > > drove about 90 miles which is terrible. Less than 20 miles a gallon.
> > > Terrible! Anyway, today I went to AutoZone to get the free scan code
> check
> > > and it turned up P0420. Does anyone know what this code means? The guy
> at
> > > AutoZone said it might be the O2 sensor. I'm thinking it's either the
O2
> > > sensor or the catalytic converter since the car has been running rich
> for
> > > the past week, and especially noticable in the last couple of days.
The
> > > check engine light was reseted today when he tested it, and it hasn't
> come
> > > on since then. After he checked it, it's been running smooth. No
> hesitation,
> > > seems it's not running rich anymore, but only time will tell. I'll
keep
> > > observing for the next few days and fix whatever needs to be fixed
over
> the
> > > weekend.
> > >
> > > Any and all help is welcome and strongly appreciated.
> > >
> > > Thank you!
> > >
> > > --Viktor
> >
> > According to my manual--PO420-- shows up as
> > "Catalyst system efficiency below threshold."
> > I don't know what this means--can anybody else interpret what this
means?
>
>

 

Hello Yuri,

Thanks for the informative reply.

So basically, if the O2 sensor is damaged, even if the engine and the rest
of the emission system is OK, it would still run rich because there's no
appropriate feedback from the O2 sensor, am I getting this right? So if the
second O2 sensor is the problem, then replacing it will get the car back to
running normal, right?

I pray to God it's not the catalytic converter because I'm a little low on
the money right now. The second O2 sensor is $83 and the first one is $109
at AutoZone. That's not too bad compared to a new catalytic converter, as
you said running in the few hundreds' range.

If anyone has more information they'd like to offer, I'm listening.

Thanks!

--Viktor

"Yuri Nebogatov" <alexneb@videotron.ca> wrote in message
news_WVb.59351$km5.1214477@wagner.videotron.net. ..
> yea, it means the 02 sensor after the cat indicates that the mixture is
too
> fuel-rich.... either the 2nd heater 02 circuit is malfunctioning, or (as
it
> has been mentionned here), the catalytic converter is failing... in wich
> case it sucks to be you cuz thats one expensive replacement.
>
> Get a real mechanic to check it out, if it's just the sensor, those should
> go for under 80$ (i'm talking about the 2nd O2 sensor, not the first one
> located on top of the cat).
> It takes about 2 mins to install one, but you need to warm up the engine
> first a bit, since the catalytic converter expands when warm and makes
> installation easier.
>
> If you need to replace the converter, thats anywhere from 170 - 400 $
right
> there, depending on the model ....
>
> These are, of course, prices for OEM or good brands ....
> Bosch, etc...
>
> ANd you're right, if the code is lit - this indicates to the ECU that
there
> is a malfunciton with the censor, which in turn disables the real-time
fuel
> control... which is made to allow for optimum fuel /air ratio (something
> that the 02 sensor monitors).
>
> In case of trouble, the car runs in open-loop mode, i.e. it reads data
from
> fuel injection tables... regardless of weither it makes for a healthy
> fuel/air mixture... thus your car is "running rich".
>
> Hope any of this was helpful
>
> peace out
>
>
>
>
>
> "T. Nelson" <tnelson@nospam.com> wrote in message
> news:tnelson-0902041644390001@pm1-broad-102.snlo.dialup.fix.net...
> > In article <eaSdna0OT-5qlrXdRVn-hg@comcast.com>, "electricked"
> > <welcomehowcome@hotmail.com> wrote:
> >
> > > Hello all,
> > >
> > > I posted earlier with some questions regarding the check enging light
> that
> > > came on few days ago. I put about 5 gallons of gas on my last stop and
> it
> > > drove about 90 miles which is terrible. Less than 20 miles a gallon.
> > > Terrible! Anyway, today I went to AutoZone to get the free scan code
> check
> > > and it turned up P0420. Does anyone know what this code means? The guy
> at
> > > AutoZone said it might be the O2 sensor. I'm thinking it's either the
O2
> > > sensor or the catalytic converter since the car has been running rich
> for
> > > the past week, and especially noticable in the last couple of days.
The
> > > check engine light was reseted today when he tested it, and it hasn't
> come
> > > on since then. After he checked it, it's been running smooth. No
> hesitation,
> > > seems it's not running rich anymore, but only time will tell. I'll
keep
> > > observing for the next few days and fix whatever needs to be fixed
over
> the
> > > weekend.
> > >
> > > Any and all help is welcome and strongly appreciated.
> > >
> > > Thank you!
> > >
> > > --Viktor
> >
> > According to my manual--PO420-- shows up as
> > "Catalyst system efficiency below threshold."
> > I don't know what this means--can anybody else interpret what this
means?
>
>

 

Hello Yuri,

Thanks for the informative reply.

So basically, if the O2 sensor is damaged, even if the engine and the rest
of the emission system is OK, it would still run rich because there's no
appropriate feedback from the O2 sensor, am I getting this right? So if the
second O2 sensor is the problem, then replacing it will get the car back to
running normal, right?

I pray to God it's not the catalytic converter because I'm a little low on
the money right now. The second O2 sensor is $83 and the first one is $109
at AutoZone. That's not too bad compared to a new catalytic converter, as
you said running in the few hundreds' range.

If anyone has more information they'd like to offer, I'm listening.

Thanks!

--Viktor

"Yuri Nebogatov" <alexneb@videotron.ca> wrote in message
news_WVb.59351$km5.1214477@wagner.videotron.net. ..
> yea, it means the 02 sensor after the cat indicates that the mixture is
too
> fuel-rich.... either the 2nd heater 02 circuit is malfunctioning, or (as
it
> has been mentionned here), the catalytic converter is failing... in wich
> case it sucks to be you cuz thats one expensive replacement.
>
> Get a real mechanic to check it out, if it's just the sensor, those should
> go for under 80$ (i'm talking about the 2nd O2 sensor, not the first one
> located on top of the cat).
> It takes about 2 mins to install one, but you need to warm up the engine
> first a bit, since the catalytic converter expands when warm and makes
> installation easier.
>
> If you need to replace the converter, thats anywhere from 170 - 400 $
right
> there, depending on the model ....
>
> These are, of course, prices for OEM or good brands ....
> Bosch, etc...
>
> ANd you're right, if the code is lit - this indicates to the ECU that
there
> is a malfunciton with the censor, which in turn disables the real-time
fuel
> control... which is made to allow for optimum fuel /air ratio (something
> that the 02 sensor monitors).
>
> In case of trouble, the car runs in open-loop mode, i.e. it reads data
from
> fuel injection tables... regardless of weither it makes for a healthy
> fuel/air mixture... thus your car is "running rich".
>
> Hope any of this was helpful
>
> peace out
>
>
>
>
>
> "T. Nelson" <tnelson@nospam.com> wrote in message
> news:tnelson-0902041644390001@pm1-broad-102.snlo.dialup.fix.net...
> > In article <eaSdna0OT-5qlrXdRVn-hg@comcast.com>, "electricked"
> > <welcomehowcome@hotmail.com> wrote:
> >
> > > Hello all,
> > >
> > > I posted earlier with some questions regarding the check enging light
> that
> > > came on few days ago. I put about 5 gallons of gas on my last stop and
> it
> > > drove about 90 miles which is terrible. Less than 20 miles a gallon.
> > > Terrible! Anyway, today I went to AutoZone to get the free scan code
> check
> > > and it turned up P0420. Does anyone know what this code means? The guy
> at
> > > AutoZone said it might be the O2 sensor. I'm thinking it's either the
O2
> > > sensor or the catalytic converter since the car has been running rich
> for
> > > the past week, and especially noticable in the last couple of days.
The
> > > check engine light was reseted today when he tested it, and it hasn't
> come
> > > on since then. After he checked it, it's been running smooth. No
> hesitation,
> > > seems it's not running rich anymore, but only time will tell. I'll
keep
> > > observing for the next few days and fix whatever needs to be fixed
over
> the
> > > weekend.
> > >
> > > Any and all help is welcome and strongly appreciated.
> > >
> > > Thank you!
> > >
> > > --Viktor
> >
> > According to my manual--PO420-- shows up as
> > "Catalyst system efficiency below threshold."
> > I don't know what this means--can anybody else interpret what this
means?
>
>

 

Hello Yuri,

Thanks for the informative reply.

So basically, if the O2 sensor is damaged, even if the engine and the rest
of the emission system is OK, it would still run rich because there's no
appropriate feedback from the O2 sensor, am I getting this right? So if the
second O2 sensor is the problem, then replacing it will get the car back to
running normal, right?

I pray to God it's not the catalytic converter because I'm a little low on
the money right now. The second O2 sensor is $83 and the first one is $109
at AutoZone. That's not too bad compared to a new catalytic converter, as
you said running in the few hundreds' range.

If anyone has more information they'd like to offer, I'm listening.

Thanks!

--Viktor

"Yuri Nebogatov" <alexneb@videotron.ca> wrote in message
news_WVb.59351$km5.1214477@wagner.videotron.net. ..
> yea, it means the 02 sensor after the cat indicates that the mixture is
too
> fuel-rich.... either the 2nd heater 02 circuit is malfunctioning, or (as
it
> has been mentionned here), the catalytic converter is failing... in wich
> case it sucks to be you cuz thats one expensive replacement.
>
> Get a real mechanic to check it out, if it's just the sensor, those should
> go for under 80$ (i'm talking about the 2nd O2 sensor, not the first one
> located on top of the cat).
> It takes about 2 mins to install one, but you need to warm up the engine
> first a bit, since the catalytic converter expands when warm and makes
> installation easier.
>
> If you need to replace the converter, thats anywhere from 170 - 400 $
right
> there, depending on the model ....
>
> These are, of course, prices for OEM or good brands ....
> Bosch, etc...
>
> ANd you're right, if the code is lit - this indicates to the ECU that
there
> is a malfunciton with the censor, which in turn disables the real-time
fuel
> control... which is made to allow for optimum fuel /air ratio (something
> that the 02 sensor monitors).
>
> In case of trouble, the car runs in open-loop mode, i.e. it reads data
from
> fuel injection tables... regardless of weither it makes for a healthy
> fuel/air mixture... thus your car is "running rich".
>
> Hope any of this was helpful
>
> peace out
>
>
>
>
>
> "T. Nelson" <tnelson@nospam.com> wrote in message
> news:tnelson-0902041644390001@pm1-broad-102.snlo.dialup.fix.net...
> > In article <eaSdna0OT-5qlrXdRVn-hg@comcast.com>, "electricked"
> > <welcomehowcome@hotmail.com> wrote:
> >
> > > Hello all,
> > >
> > > I posted earlier with some questions regarding the check enging light
> that
> > > came on few days ago. I put about 5 gallons of gas on my last stop and
> it
> > > drove about 90 miles which is terrible. Less than 20 miles a gallon.
> > > Terrible! Anyway, today I went to AutoZone to get the free scan code
> check
> > > and it turned up P0420. Does anyone know what this code means? The guy
> at
> > > AutoZone said it might be the O2 sensor. I'm thinking it's either the
O2
> > > sensor or the catalytic converter since the car has been running rich
> for
> > > the past week, and especially noticable in the last couple of days.
The
> > > check engine light was reseted today when he tested it, and it hasn't
> come
> > > on since then. After he checked it, it's been running smooth. No
> hesitation,
> > > seems it's not running rich anymore, but only time will tell. I'll
keep
> > > observing for the next few days and fix whatever needs to be fixed
over
> the
> > > weekend.
> > >
> > > Any and all help is welcome and strongly appreciated.
> > >
> > > Thank you!
> > >
> > > --Viktor
> >
> > According to my manual--PO420-- shows up as
> > "Catalyst system efficiency below threshold."
> > I don't know what this means--can anybody else interpret what this
means?
>
>

 

Once again thanks Yuri! Can't wait to check out your design. Very
interesting

And again, more information is welcome

Thank you all!

--Viktor

"Yuri Nebogatov" <alexneb@videotron.ca> wrote in message
newsdZVb.30183$GE5.1425702@weber.videotron.net.. .
> Yea, right on the money
>
> However, don't dispair.... I personally think that your problem lies with
> the cat, but thats just me.
> HOWEVER, thats goodnews, regardless of what you may think. Only the 1st O2
> sensor's data is used for the fuel/air mixture adjustement, the 2nd one
only
> monitors the efficiency of the catalytic converter. The dumb thing is, if
> either of the sensors set a code, the engine might still be running in
> open-loop mode (that is, lotsa gaz.... bad mileage).
>
> It is techincally not dangerous (unless you're a green peace freak) to run
> with a failing converter or a malfunctioning 2nd 02 sensor, as long as the
> 1st one (the one on top of the cat is working fine).
>
> Here's the deal : there's a way to trick the ECU into thinking that the
2nd
> 02 sensor is working normally, even if it's busted or not even there. You
> need to basically have the 02 output voltage in the right range (around
0.45
> volts), and trick the heating circuit into thinking there's "something to
> heat" - by shorting the terminal 3 and 4 of the connector with a resistor.
> I'm a bit busy right now with school and whatnot, but this weekend when I
> got some time, i'll design this thing for ya (its very basic, nothing but
> resistors and capacitors) so you can try to plug it in, instead of the o2
> sensor - for peace of mind Again, this would only work for the 2nd
> sensor, the primary sensor is essential to good vehicle operation.
>
>
>
> "electricked" <welcomehowcome@hotmail.com> wrote in message
> news:a8ednV2TQv1E1LXd4p2dnA@comcast.com...
> > Hello Yuri,
> >
> > Thanks for the informative reply.
> >
> > So basically, if the O2 sensor is damaged, even if the engine and the
rest
> > of the emission system is OK, it would still run rich because there's no
> > appropriate feedback from the O2 sensor, am I getting this right? So if
> the
> > second O2 sensor is the problem, then replacing it will get the car back
> to
> > running normal, right?
> >
> > I pray to God it's not the catalytic converter because I'm a little low
on
> > the money right now. The second O2 sensor is $83 and the first one is
$109
> > at AutoZone. That's not too bad compared to a new catalytic converter,
as
> > you said running in the few hundreds' range.
> >
> > If anyone has more information they'd like to offer, I'm listening.
> >
> > Thanks!
> >
> > --Viktor
> >
> > "Yuri Nebogatov" <alexneb@videotron.ca> wrote in message
> > news_WVb.59351$km5.1214477@wagner.videotron.net. ..
> > > yea, it means the 02 sensor after the cat indicates that the mixture
is
> > too
> > > fuel-rich.... either the 2nd heater 02 circuit is malfunctioning, or
(as
> > it
> > > has been mentionned here), the catalytic converter is failing... in
wich
> > > case it sucks to be you cuz thats one expensive replacement.
> > >
> > > Get a real mechanic to check it out, if it's just the sensor, those
> should
> > > go for under 80$ (i'm talking about the 2nd O2 sensor, not the first
one
> > > located on top of the cat).
> > > It takes about 2 mins to install one, but you need to warm up the
engine
> > > first a bit, since the catalytic converter expands when warm and makes
> > > installation easier.
> > >
> > > If you need to replace the converter, thats anywhere from 170 - 400 $
> > right
> > > there, depending on the model ....
> > >
> > > These are, of course, prices for OEM or good brands ....
> > > Bosch, etc...
> > >
> > > ANd you're right, if the code is lit - this indicates to the ECU that
> > there
> > > is a malfunciton with the censor, which in turn disables the real-time
> > fuel
> > > control... which is made to allow for optimum fuel /air ratio
(something
> > > that the 02 sensor monitors).
> > >
> > > In case of trouble, the car runs in open-loop mode, i.e. it reads data
> > from
> > > fuel injection tables... regardless of weither it makes for a healthy
> > > fuel/air mixture... thus your car is "running rich".
> > >
> > > Hope any of this was helpful
> > >
> > > peace out
> > >
> > >
> > >
> > >
> > >
> > > "T. Nelson" <tnelson@nospam.com> wrote in message
> > > news:tnelson-0902041644390001@pm1-broad-102.snlo.dialup.fix.net...
> > > > In article <eaSdna0OT-5qlrXdRVn-hg@comcast.com>, "electricked"
> > > > <welcomehowcome@hotmail.com> wrote:
> > > >
> > > > > Hello all,
> > > > >
> > > > > I posted earlier with some questions regarding the check enging
> light
> > > that
> > > > > came on few days ago. I put about 5 gallons of gas on my last stop
> and
> > > it
> > > > > drove about 90 miles which is terrible. Less than 20 miles a
gallon.
> > > > > Terrible! Anyway, today I went to AutoZone to get the free scan
code
> > > check
> > > > > and it turned up P0420. Does anyone know what this code means? The
> guy
> > > at
> > > > > AutoZone said it might be the O2 sensor. I'm thinking it's either
> the
> > O2
> > > > > sensor or the catalytic converter since the car has been running
> rich
> > > for
> > > > > the past week, and especially noticable in the last couple of
days.
> > The
> > > > > check engine light was reseted today when he tested it, and it
> hasn't
> > > come
> > > > > on since then. After he checked it, it's been running smooth. No
> > > hesitation,
> > > > > seems it's not running rich anymore, but only time will tell. I'll
> > keep
> > > > > observing for the next few days and fix whatever needs to be fixed
> > over
> > > the
> > > > > weekend.
> > > > >
> > > > > Any and all help is welcome and strongly appreciated.
> > > > >
> > > > > Thank you!
> > > > >
> > > > > --Viktor
> > > >
> > > > According to my manual--PO420-- shows up as
> > > > "Catalyst system efficiency below threshold."
> > > > I don't know what this means--can anybody else interpret what this
> > means?
> > >
> > >
> >
> >
>
>

 

Once again thanks Yuri! Can't wait to check out your design. Very
interesting

And again, more information is welcome

Thank you all!

--Viktor

"Yuri Nebogatov" <alexneb@videotron.ca> wrote in message
newsdZVb.30183$GE5.1425702@weber.videotron.net.. .
> Yea, right on the money
>
> However, don't dispair.... I personally think that your problem lies with
> the cat, but thats just me.
> HOWEVER, thats goodnews, regardless of what you may think. Only the 1st O2
> sensor's data is used for the fuel/air mixture adjustement, the 2nd one
only
> monitors the efficiency of the catalytic converter. The dumb thing is, if
> either of the sensors set a code, the engine might still be running in
> open-loop mode (that is, lotsa gaz.... bad mileage).
>
> It is techincally not dangerous (unless you're a green peace freak) to run
> with a failing converter or a malfunctioning 2nd 02 sensor, as long as the
> 1st one (the one on top of the cat is working fine).
>
> Here's the deal : there's a way to trick the ECU into thinking that the
2nd
> 02 sensor is working normally, even if it's busted or not even there. You
> need to basically have the 02 output voltage in the right range (around
0.45
> volts), and trick the heating circuit into thinking there's "something to
> heat" - by shorting the terminal 3 and 4 of the connector with a resistor.
> I'm a bit busy right now with school and whatnot, but this weekend when I
> got some time, i'll design this thing for ya (its very basic, nothing but
> resistors and capacitors) so you can try to plug it in, instead of the o2
> sensor - for peace of mind Again, this would only work for the 2nd
> sensor, the primary sensor is essential to good vehicle operation.
>
>
>
> "electricked" <welcomehowcome@hotmail.com> wrote in message
> news:a8ednV2TQv1E1LXd4p2dnA@comcast.com...
> > Hello Yuri,
> >
> > Thanks for the informative reply.
> >
> > So basically, if the O2 sensor is damaged, even if the engine and the
rest
> > of the emission system is OK, it would still run rich because there's no
> > appropriate feedback from the O2 sensor, am I getting this right? So if
> the
> > second O2 sensor is the problem, then replacing it will get the car back
> to
> > running normal, right?
> >
> > I pray to God it's not the catalytic converter because I'm a little low
on
> > the money right now. The second O2 sensor is $83 and the first one is
$109
> > at AutoZone. That's not too bad compared to a new catalytic converter,
as
> > you said running in the few hundreds' range.
> >
> > If anyone has more information they'd like to offer, I'm listening.
> >
> > Thanks!
> >
> > --Viktor
> >
> > "Yuri Nebogatov" <alexneb@videotron.ca> wrote in message
> > news_WVb.59351$km5.1214477@wagner.videotron.net. ..
> > > yea, it means the 02 sensor after the cat indicates that the mixture
is
> > too
> > > fuel-rich.... either the 2nd heater 02 circuit is malfunctioning, or
(as
> > it
> > > has been mentionned here), the catalytic converter is failing... in
wich
> > > case it sucks to be you cuz thats one expensive replacement.
> > >
> > > Get a real mechanic to check it out, if it's just the sensor, those
> should
> > > go for under 80$ (i'm talking about the 2nd O2 sensor, not the first
one
> > > located on top of the cat).
> > > It takes about 2 mins to install one, but you need to warm up the
engine
> > > first a bit, since the catalytic converter expands when warm and makes
> > > installation easier.
> > >
> > > If you need to replace the converter, thats anywhere from 170 - 400 $
> > right
> > > there, depending on the model ....
> > >
> > > These are, of course, prices for OEM or good brands ....
> > > Bosch, etc...
> > >
> > > ANd you're right, if the code is lit - this indicates to the ECU that
> > there
> > > is a malfunciton with the censor, which in turn disables the real-time
> > fuel
> > > control... which is made to allow for optimum fuel /air ratio
(something
> > > that the 02 sensor monitors).
> > >
> > > In case of trouble, the car runs in open-loop mode, i.e. it reads data
> > from
> > > fuel injection tables... regardless of weither it makes for a healthy
> > > fuel/air mixture... thus your car is "running rich".
> > >
> > > Hope any of this was helpful
> > >
> > > peace out
> > >
> > >
> > >
> > >
> > >
> > > "T. Nelson" <tnelson@nospam.com> wrote in message
> > > news:tnelson-0902041644390001@pm1-broad-102.snlo.dialup.fix.net...
> > > > In article <eaSdna0OT-5qlrXdRVn-hg@comcast.com>, "electricked"
> > > > <welcomehowcome@hotmail.com> wrote:
> > > >
> > > > > Hello all,
> > > > >
> > > > > I posted earlier with some questions regarding the check enging
> light
> > > that
> > > > > came on few days ago. I put about 5 gallons of gas on my last stop
> and
> > > it
> > > > > drove about 90 miles which is terrible. Less than 20 miles a
gallon.
> > > > > Terrible! Anyway, today I went to AutoZone to get the free scan
code
> > > check
> > > > > and it turned up P0420. Does anyone know what this code means? The
> guy
> > > at
> > > > > AutoZone said it might be the O2 sensor. I'm thinking it's either
> the
> > O2
> > > > > sensor or the catalytic converter since the car has been running
> rich
> > > for
> > > > > the past week, and especially noticable in the last couple of
days.
> > The
> > > > > check engine light was reseted today when he tested it, and it
> hasn't
> > > come
> > > > > on since then. After he checked it, it's been running smooth. No
> > > hesitation,
> > > > > seems it's not running rich anymore, but only time will tell. I'll
> > keep
> > > > > observing for the next few days and fix whatever needs to be fixed
> > over
> > > the
> > > > > weekend.
> > > > >
> > > > > Any and all help is welcome and strongly appreciated.
> > > > >
> > > > > Thank you!
> > > > >
> > > > > --Viktor
> > > >
> > > > According to my manual--PO420-- shows up as
> > > > "Catalyst system efficiency below threshold."
> > > > I don't know what this means--can anybody else interpret what this
> > means?
> > >
> > >
> >
> >
>
>

 

Once again thanks Yuri! Can't wait to check out your design. Very
interesting

And again, more information is welcome

Thank you all!

--Viktor

"Yuri Nebogatov" <alexneb@videotron.ca> wrote in message
newsdZVb.30183$GE5.1425702@weber.videotron.net.. .
> Yea, right on the money
>
> However, don't dispair.... I personally think that your problem lies with
> the cat, but thats just me.
> HOWEVER, thats goodnews, regardless of what you may think. Only the 1st O2
> sensor's data is used for the fuel/air mixture adjustement, the 2nd one
only
> monitors the efficiency of the catalytic converter. The dumb thing is, if
> either of the sensors set a code, the engine might still be running in
> open-loop mode (that is, lotsa gaz.... bad mileage).
>
> It is techincally not dangerous (unless you're a green peace freak) to run
> with a failing converter or a malfunctioning 2nd 02 sensor, as long as the
> 1st one (the one on top of the cat is working fine).
>
> Here's the deal : there's a way to trick the ECU into thinking that the
2nd
> 02 sensor is working normally, even if it's busted or not even there. You
> need to basically have the 02 output voltage in the right range (around
0.45
> volts), and trick the heating circuit into thinking there's "something to
> heat" - by shorting the terminal 3 and 4 of the connector with a resistor.
> I'm a bit busy right now with school and whatnot, but this weekend when I
> got some time, i'll design this thing for ya (its very basic, nothing but
> resistors and capacitors) so you can try to plug it in, instead of the o2
> sensor - for peace of mind Again, this would only work for the 2nd
> sensor, the primary sensor is essential to good vehicle operation.
>
>
>
> "electricked" <welcomehowcome@hotmail.com> wrote in message
> news:a8ednV2TQv1E1LXd4p2dnA@comcast.com...
> > Hello Yuri,
> >
> > Thanks for the informative reply.
> >
> > So basically, if the O2 sensor is damaged, even if the engine and the
rest
> > of the emission system is OK, it would still run rich because there's no
> > appropriate feedback from the O2 sensor, am I getting this right? So if
> the
> > second O2 sensor is the problem, then replacing it will get the car back
> to
> > running normal, right?
> >
> > I pray to God it's not the catalytic converter because I'm a little low
on
> > the money right now. The second O2 sensor is $83 and the first one is
$109
> > at AutoZone. That's not too bad compared to a new catalytic converter,
as
> > you said running in the few hundreds' range.
> >
> > If anyone has more information they'd like to offer, I'm listening.
> >
> > Thanks!
> >
> > --Viktor
> >
> > "Yuri Nebogatov" <alexneb@videotron.ca> wrote in message
> > news_WVb.59351$km5.1214477@wagner.videotron.net. ..
> > > yea, it means the 02 sensor after the cat indicates that the mixture
is
> > too
> > > fuel-rich.... either the 2nd heater 02 circuit is malfunctioning, or
(as
> > it
> > > has been mentionned here), the catalytic converter is failing... in
wich
> > > case it sucks to be you cuz thats one expensive replacement.
> > >
> > > Get a real mechanic to check it out, if it's just the sensor, those
> should
> > > go for under 80$ (i'm talking about the 2nd O2 sensor, not the first
one
> > > located on top of the cat).
> > > It takes about 2 mins to install one, but you need to warm up the
engine
> > > first a bit, since the catalytic converter expands when warm and makes
> > > installation easier.
> > >
> > > If you need to replace the converter, thats anywhere from 170 - 400 $
> > right
> > > there, depending on the model ....
> > >
> > > These are, of course, prices for OEM or good brands ....
> > > Bosch, etc...
> > >
> > > ANd you're right, if the code is lit - this indicates to the ECU that
> > there
> > > is a malfunciton with the censor, which in turn disables the real-time
> > fuel
> > > control... which is made to allow for optimum fuel /air ratio
(something
> > > that the 02 sensor monitors).
> > >
> > > In case of trouble, the car runs in open-loop mode, i.e. it reads data
> > from
> > > fuel injection tables... regardless of weither it makes for a healthy
> > > fuel/air mixture... thus your car is "running rich".
> > >
> > > Hope any of this was helpful
> > >
> > > peace out
> > >
> > >
> > >
> > >
> > >
> > > "T. Nelson" <tnelson@nospam.com> wrote in message
> > > news:tnelson-0902041644390001@pm1-broad-102.snlo.dialup.fix.net...
> > > > In article <eaSdna0OT-5qlrXdRVn-hg@comcast.com>, "electricked"
> > > > <welcomehowcome@hotmail.com> wrote:
> > > >
> > > > > Hello all,
> > > > >
> > > > > I posted earlier with some questions regarding the check enging
> light
> > > that
> > > > > came on few days ago. I put about 5 gallons of gas on my last stop
> and
> > > it
> > > > > drove about 90 miles which is terrible. Less than 20 miles a
gallon.
> > > > > Terrible! Anyway, today I went to AutoZone to get the free scan
code
> > > check
> > > > > and it turned up P0420. Does anyone know what this code means? The
> guy
> > > at
> > > > > AutoZone said it might be the O2 sensor. I'm thinking it's either
> the
> > O2
> > > > > sensor or the catalytic converter since the car has been running
> rich
> > > for
> > > > > the past week, and especially noticable in the last couple of
days.
> > The
> > > > > check engine light was reseted today when he tested it, and it
> hasn't
> > > come
> > > > > on since then. After he checked it, it's been running smooth. No
> > > hesitation,
> > > > > seems it's not running rich anymore, but only time will tell. I'll
> > keep
> > > > > observing for the next few days and fix whatever needs to be fixed
> > over
> > > the
> > > > > weekend.
> > > > >
> > > > > Any and all help is welcome and strongly appreciated.
> > > > >
> > > > > Thank you!
> > > > >
> > > > > --Viktor
> > > >
> > > > According to my manual--PO420-- shows up as
> > > > "Catalyst system efficiency below threshold."
> > > > I don't know what this means--can anybody else interpret what this
> > means?
> > >
> > >
> >
> >
>
>

 

Once again thanks Yuri! Can't wait to check out your design. Very
interesting

And again, more information is welcome

Thank you all!

--Viktor

"Yuri Nebogatov" <alexneb@videotron.ca> wrote in message
newsdZVb.30183$GE5.1425702@weber.videotron.net.. .
> Yea, right on the money
>
> However, don't dispair.... I personally think that your problem lies with
> the cat, but thats just me.
> HOWEVER, thats goodnews, regardless of what you may think. Only the 1st O2
> sensor's data is used for the fuel/air mixture adjustement, the 2nd one
only
> monitors the efficiency of the catalytic converter. The dumb thing is, if
> either of the sensors set a code, the engine might still be running in
> open-loop mode (that is, lotsa gaz.... bad mileage).
>
> It is techincally not dangerous (unless you're a green peace freak) to run
> with a failing converter or a malfunctioning 2nd 02 sensor, as long as the
> 1st one (the one on top of the cat is working fine).
>
> Here's the deal : there's a way to trick the ECU into thinking that the
2nd
> 02 sensor is working normally, even if it's busted or not even there. You
> need to basically have the 02 output voltage in the right range (around
0.45
> volts), and trick the heating circuit into thinking there's "something to
> heat" - by shorting the terminal 3 and 4 of the connector with a resistor.
> I'm a bit busy right now with school and whatnot, but this weekend when I
> got some time, i'll design this thing for ya (its very basic, nothing but
> resistors and capacitors) so you can try to plug it in, instead of the o2
> sensor - for peace of mind Again, this would only work for the 2nd
> sensor, the primary sensor is essential to good vehicle operation.
>
>
>
> "electricked" <welcomehowcome@hotmail.com> wrote in message
> news:a8ednV2TQv1E1LXd4p2dnA@comcast.com...
> > Hello Yuri,
> >
> > Thanks for the informative reply.
> >
> > So basically, if the O2 sensor is damaged, even if the engine and the
rest
> > of the emission system is OK, it would still run rich because there's no
> > appropriate feedback from the O2 sensor, am I getting this right? So if
> the
> > second O2 sensor is the problem, then replacing it will get the car back
> to
> > running normal, right?
> >
> > I pray to God it's not the catalytic converter because I'm a little low
on
> > the money right now. The second O2 sensor is $83 and the first one is
$109
> > at AutoZone. That's not too bad compared to a new catalytic converter,
as
> > you said running in the few hundreds' range.
> >
> > If anyone has more information they'd like to offer, I'm listening.
> >
> > Thanks!
> >
> > --Viktor
> >
> > "Yuri Nebogatov" <alexneb@videotron.ca> wrote in message
> > news_WVb.59351$km5.1214477@wagner.videotron.net. ..
> > > yea, it means the 02 sensor after the cat indicates that the mixture
is
> > too
> > > fuel-rich.... either the 2nd heater 02 circuit is malfunctioning, or
(as
> > it
> > > has been mentionned here), the catalytic converter is failing... in
wich
> > > case it sucks to be you cuz thats one expensive replacement.
> > >
> > > Get a real mechanic to check it out, if it's just the sensor, those
> should
> > > go for under 80$ (i'm talking about the 2nd O2 sensor, not the first
one
> > > located on top of the cat).
> > > It takes about 2 mins to install one, but you need to warm up the
engine
> > > first a bit, since the catalytic converter expands when warm and makes
> > > installation easier.
> > >
> > > If you need to replace the converter, thats anywhere from 170 - 400 $
> > right
> > > there, depending on the model ....
> > >
> > > These are, of course, prices for OEM or good brands ....
> > > Bosch, etc...
> > >
> > > ANd you're right, if the code is lit - this indicates to the ECU that
> > there
> > > is a malfunciton with the censor, which in turn disables the real-time
> > fuel
> > > control... which is made to allow for optimum fuel /air ratio
(something
> > > that the 02 sensor monitors).
> > >
> > > In case of trouble, the car runs in open-loop mode, i.e. it reads data
> > from
> > > fuel injection tables... regardless of weither it makes for a healthy
> > > fuel/air mixture... thus your car is "running rich".
> > >
> > > Hope any of this was helpful
> > >
> > > peace out
> > >
> > >
> > >
> > >
> > >
> > > "T. Nelson" <tnelson@nospam.com> wrote in message
> > > news:tnelson-0902041644390001@pm1-broad-102.snlo.dialup.fix.net...
> > > > In article <eaSdna0OT-5qlrXdRVn-hg@comcast.com>, "electricked"
> > > > <welcomehowcome@hotmail.com> wrote:
> > > >
> > > > > Hello all,
> > > > >
> > > > > I posted earlier with some questions regarding the check enging
> light
> > > that
> > > > > came on few days ago. I put about 5 gallons of gas on my last stop
> and
> > > it
> > > > > drove about 90 miles which is terrible. Less than 20 miles a
gallon.
> > > > > Terrible! Anyway, today I went to AutoZone to get the free scan
code
> > > check
> > > > > and it turned up P0420. Does anyone know what this code means? The
> guy
> > > at
> > > > > AutoZone said it might be the O2 sensor. I'm thinking it's either
> the
> > O2
> > > > > sensor or the catalytic converter since the car has been running
> rich
> > > for
> > > > > the past week, and especially noticable in the last couple of
days.
> > The
> > > > > check engine light was reseted today when he tested it, and it
> hasn't
> > > come
> > > > > on since then. After he checked it, it's been running smooth. No
> > > hesitation,
> > > > > seems it's not running rich anymore, but only time will tell. I'll
> > keep
> > > > > observing for the next few days and fix whatever needs to be fixed
> > over
> > > the
> > > > > weekend.
> > > > >
> > > > > Any and all help is welcome and strongly appreciated.
> > > > >
> > > > > Thank you!
> > > > >
> > > > > --Viktor
> > > >
> > > > According to my manual--PO420-- shows up as
> > > > "Catalyst system efficiency below threshold."
> > > > I don't know what this means--can anybody else interpret what this
> > means?
> > >
> > >
> >
> >
>
>

 

In article <6IqdnTwJsMj_67Xd4p2dnA@comcast.com>, "electricked"
<welcomehowcome@hotmail.com> wrote:

> Once again thanks Yuri! Can't wait to check out your design. Very
> interesting
>
> And again, more information is welcome
>
> Thank you all!
>
> --Viktor

Viktor,
I read all of the interesting posts on this subject. It appears that some
of the posters believe that you have a bad sensor instead of a problem
with the catalytic converter. I just wanted to add that at this point in
time, you don't know for sure whether the problem is with the catalytic
converter or the sensor. You might want to check out the warranty
information that came with your vehicle. It's possible that your catalytic
converter might still be covered--I'm just guessing. I suggest that you
have your vehicle checked by a mechanic that you trust to determine
whether the catalytic converter or the sensor is the source of the
problem. This is especially true if your state requires a pollution or
emission test each year.