Honda Car Forum

The question of whether an O2 sensor can be bad enough to cause drivability
or fuel economy problems without triggering OBDII codes has another data
point.

In the alt.autos.subaru forum somebody asked for help sorting out very
troublesome hesitation after slowing in a 2006 Outback. A respondent had the
same problem in his car, and pressured the dealer to do *something*! The
dealer replaced the O2 sensor (front one, I presume) in spite of lack of
diagnostic codes and the symptom disappeared.

Mike

Michael Pardee wrote:
> The question of whether an O2 sensor can be bad enough to cause drivability
> or fuel economy problems without triggering OBDII codes has another data
> point.
>
> In the alt.autos.subaru forum somebody asked for help sorting out very
> troublesome hesitation after slowing in a 2006 Outback. A respondent had the
> same problem in his car, and pressured the dealer to do *something*! The
> dealer replaced the O2 sensor (front one, I presume) in spite of lack of
> diagnostic codes and the symptom disappeared.
>
> Mike
>
>
my experience is yes, it can definitely scratch that itch. with cheapo
aftermarket sensors, my '89, which has a slight tendency to hesitiation
anyway, is /way/ worse. no codes. but when i use a new oem sensor,
that problem all but disappears.

Am 89 is not OBDII compliant and does not monitor the sensors that close and
the sensors are totally different. The OBDII system monitors heater current
and voltage and switching times and voltage to very precisely determine what
they are doing. The chance of them causing a problem without setting a code
is extremely slim. They can be setting sub codes long before turning on the
light on the dash. The information in the computer should be thoroughly
analyzed as swapping parts is expensive and could just be masking the real
problem.


"jim beam" <nospam@example.net> wrote in message
news:-tSdnUzA2tZufdbZnZ2dnUVZ_tKdnZ2d@speakeasy.net...
> Michael Pardee wrote:
>> The question of whether an O2 sensor can be bad enough to cause
>> drivability or fuel economy problems without triggering OBDII codes has
>> another data point.
>>
>> In the alt.autos.subaru forum somebody asked for help sorting out very
>> troublesome hesitation after slowing in a 2006 Outback. A respondent had
>> the same problem in his car, and pressured the dealer to do *something*!
>> The dealer replaced the O2 sensor (front one, I presume) in spite of lack
>> of diagnostic codes and the symptom disappeared.
>>
>> Mike
> my experience is yes, it can definitely scratch that itch. with cheapo
> aftermarket sensors, my '89, which has a slight tendency to hesitiation
> anyway, is /way/ worse. no codes. but when i use a new oem sensor, that
> problem all but disappears.

"Woody" <TheDuck@pond.net> wrote in message
news:8s33g.69065$H71.136@newssvr13.news.prodigy.co m...
> Am 89 is not OBDII compliant and does not monitor the sensors that close
> and the sensors are totally different. The OBDII system monitors heater
> current and voltage and switching times and voltage to very precisely
> determine what they are doing. The chance of them causing a problem
> without setting a code is extremely slim. They can be setting sub codes
> long before turning on the light on the dash. The information in the
> computer should be thoroughly analyzed as swapping parts is expensive and
> could just be masking the real problem.
>
>
I would have thought OBDII would catch O2 weakness, too, but as the Subaru
experience illustrates it isn't necessarily so. I am puzzled what sort of
out-of-the-box defect the sensor would have that would cause it to behave so
badly and not be tattled on, though.

Mike

Michael Pardee wrote:
>
> "Woody" <TheDuck@pond.net> wrote in message
> news:8s33g.69065$H71.136@newssvr13.news.prodigy.co m...
> > Am 89 is not OBDII compliant and does not monitor the sensors that close
> > and the sensors are totally different. The OBDII system monitors heater
> > current and voltage and switching times and voltage to very precisely
> > determine what they are doing. The chance of them causing a problem
> > without setting a code is extremely slim. They can be setting sub codes
> > long before turning on the light on the dash. The information in the
> > computer should be thoroughly analyzed as swapping parts is expensive and
> > could just be masking the real problem.
> >
> >
> I would have thought OBDII would catch O2 weakness, too, but as the Subaru
> experience illustrates it isn't necessarily so. I am puzzled what sort of
> out-of-the-box defect the sensor would have that would cause it to behave so
> badly and not be tattled on, though.
>
> Mike

--------------------------------------

Maybe the out-of-the-box defect was caused by the BOX ITSELF (like it
had the word BOSCH on it)? I keep hearing horror stories about BOSCH,
and having owned Volvo and VW, I believe it.

:-(

'Curly'
--
If there are a couple of _underscores_ hidden in my return address,
you'll have to remove them to reply . . . . Thanks.

Michael Pardee wrote:
> I would have thought OBDII would catch O2 weakness, too, but as the Subaru
> experience illustrates it isn't necessarily so. I am puzzled what sort of
> out-of-the-box defect the sensor would have that would cause it to behave so
> badly and not be tattled on, though.
>
> Mike

===============================

:-) Maybe the out-of-the-box defect was caused by the BOX ITSELF (like
it
had the word BOSCH on it)? I keep hearing horror stories about BOSCH,
and having owned Volvo and VW, I believe it.

:-(

'Curly'

"'Curly Q. Links'" <motsco__@interbaun.com> wrote in
news:444CE564.A6DB1014@interbaun.com:

> Michael Pardee wrote:
>>
>> "Woody" <TheDuck@pond.net> wrote in message
>> news:8s33g.69065$H71.136@newssvr13.news.prodigy.co m...
>> > Am 89 is not OBDII compliant and does not monitor the sensors that
>> > close and the sensors are totally different. The OBDII system
>> > monitors heater current and voltage and switching times and voltage
>> > to very precisely determine what they are doing. The chance of them
>> > causing a problem without setting a code is extremely slim. They
>> > can be setting sub codes long before turning on the light on the
>> > dash. The information in the computer should be thoroughly analyzed
>> > as swapping parts is expensive and could just be masking the real
>> > problem.
>> >
>> >
>> I would have thought OBDII would catch O2 weakness, too, but as the
>> Subaru experience illustrates it isn't necessarily so. I am puzzled
>> what sort of out-of-the-box defect the sensor would have that would
>> cause it to behave so badly and not be tattled on, though.
>>
>> Mike
>
> --------------------------------------
>
> Maybe the out-of-the-box defect was caused by the BOX ITSELF (like it
> had the word BOSCH on it)? I keep hearing horror stories about BOSCH,
> and having owned Volvo and VW, I believe it.
>
> :-(
>
> 'Curly'

Bosch,the new Prince of Darkness? (Lucas being the old one)

--
Jim Yanik
jyanik
at
kua.net

I won,t believe it until I see it. Of coarse Subaru may have a defect in
their OBDII code. Bad enough to cause fuel economy problems you could
definitely see on the graph of the sensor.


"Michael Pardee" <michaeltnull@cybertrails.com> wrote in message
news:SZWdnVRoC4JHVNHZnZ2dnUVZ_s-dnZ2d@sedona.net...
> "Woody" <TheDuck@pond.net> wrote in message
> news:8s33g.69065$H71.136@newssvr13.news.prodigy.co m...
>> Am 89 is not OBDII compliant and does not monitor the sensors that close
>> and the sensors are totally different. The OBDII system monitors heater
>> current and voltage and switching times and voltage to very precisely
>> determine what they are doing. The chance of them causing a problem
>> without setting a code is extremely slim. They can be setting sub codes
>> long before turning on the light on the dash. The information in the
>> computer should be thoroughly analyzed as swapping parts is expensive and
>> could just be masking the real problem.
>>
>>
> I would have thought OBDII would catch O2 weakness, too, but as the Subaru
> experience illustrates it isn't necessarily so. I am puzzled what sort of
> out-of-the-box defect the sensor would have that would cause it to behave
> so badly and not be tattled on, though.
>
> Mike
>

Woody wrote:
> Am 89 is not OBDII compliant and does not monitor the sensors that close and
> the sensors are totally different. The OBDII system monitors heater current
> and voltage and switching times and voltage to very precisely determine what
> they are doing.

monitoring heater current allows determination of element temperature if
taken to it's logical limit and simple burn-out at its most basic.
other than that, unless it's truly sophisticated, which i doubt in a
very noisy electrical environment like under the hood of a car,
diagnostics are going to be fairly basic stuff. the primary fault
detection mode afaik is to set differential limits between primary and
secondary sensors, and trigger if exceeded.

> The chance of them causing a problem without setting a code
> is extremely slim. They can be setting sub codes long before turning on the
> light on the dash. The information in the computer should be thoroughly
> analyzed as swapping parts is expensive and could just be masking the real
> problem.

but most people take it to a shop that has testing tools. the obdc
computer therefore doesn't need to be that sophisticated. for the home
mechanic, and in the absence of these expensive diagnostics, a few parts
scavenged from a junk yard, which is where i got the sensors for my
comparisons, can be a /much/ cheaper way of determining the level of
problem.

>
>
> "jim beam" <nospam@example.net> wrote in message
> news:-tSdnUzA2tZufdbZnZ2dnUVZ_tKdnZ2d@speakeasy.net...
>
>>Michael Pardee wrote:
>>
>>>The question of whether an O2 sensor can be bad enough to cause
>>>drivability or fuel economy problems without triggering OBDII codes has
>>>another data point.
>>>
>>>In the alt.autos.subaru forum somebody asked for help sorting out very
>>>troublesome hesitation after slowing in a 2006 Outback. A respondent had
>>>the same problem in his car, and pressured the dealer to do *something*!
>>>The dealer replaced the O2 sensor (front one, I presume) in spite of lack
>>>of diagnostic codes and the symptom disappeared.
>>>
>>>Mike
>>
>>my experience is yes, it can definitely scratch that itch. with cheapo
>>aftermarket sensors, my '89, which has a slight tendency to hesitiation
>>anyway, is /way/ worse. no codes. but when i use a new oem sensor, that
>>problem all but disappears.
>
>
>

"Woody" <TheDuck@pond.net> wrote in
news:Wku3g.75554$dW3.59371@newssvr21.news.prodigy. com:

> I won,t believe it until I see it. Of coarse Subaru may have a defect
> in their OBDII code. Bad enough to cause fuel economy problems you
> could definitely see on the graph of the sensor.
>
>
> "Michael Pardee" <michaeltnull@cybertrails.com> wrote in message
> news:SZWdnVRoC4JHVNHZnZ2dnUVZ_s-dnZ2d@sedona.net...
>> "Woody" <TheDuck@pond.net> wrote in message
>> news:8s33g.69065$H71.136@newssvr13.news.prodigy.co m...
>>> Am 89 is not OBDII compliant and does not monitor the sensors that
>>> close and the sensors are totally different. The OBDII system
>>> monitors heater current and voltage and switching times and voltage
>>> to very precisely determine what they are doing. The chance of them
>>> causing a problem without setting a code is extremely slim. They can
>>> be setting sub codes long before turning on the light on the dash.
>>> The information in the computer should be thoroughly analyzed as
>>> swapping parts is expensive and could just be masking the real
>>> problem.
>>>
>>>
>> I would have thought OBDII would catch O2 weakness, too, but as the
>> Subaru experience illustrates it isn't necessarily so. I am puzzled
>> what sort of out-of-the-box defect the sensor would have that would
>> cause it to behave so badly and not be tattled on, though.
>>
>> Mike
>>
>
>
>

I did some Googling on "lazy oxygen sensor" and there were quite a number
of articles about the O2S affecting fuel economy.(without setting a code)
--
Jim Yanik
jyanik
at
kua.net