long term fuel trim

I'm trying to diagnose a p0171 error code.

I've got an actron obd II scanner from Murray's

alldata's website says:
1. install the scan tool
2. start and idle engine at normal operating temperature in the Closed Loop
3. record the data for long term fuel trim
4. turn off engine
5. turn on ignition, engine off
6. review freeze frame / failure records and record displayed data for this
diagnostic trouble code

how do I get it in the Closed Loop?
how do I get the data for long term fuel trim in the scanner?
how do I view freeze frame / failure records in the scanner?

thanks.

"Raymond" <noemail@noemail.com> wrote in
news:be_Ve.20$an4.770@news.uswest.net:
[color=blue]
> I'm trying to diagnose a p0171 error code.
>
> I've got an actron obd II scanner from Murray's
>
> alldata's website says:
> 1. install the scan tool
> 2. start and idle engine at normal operating temperature in the Closed
> Loop 3. record the data for long term fuel trim
> 4. turn off engine
> 5. turn on ignition, engine off
> 6. review freeze frame / failure records and record displayed data for
> this diagnostic trouble code
>
> how do I get it in the Closed Loop?[/color]



"Closed-loop" occurs when the ECM sees that the coolant temperature is at
90C (194F), and the throttle is NOT wide open.

If the engine is less than full-warm, you run the risk of dropping to open-
loop, which is when the upstream O2 sensor is not used as ECM input.


--
TeGGeR®

The Unofficial Honda/Acura FAQ
[url]www.tegger.com/hondafaq/[/url]

"Raymond" <noemail@noemail.com> wrote in message
news:be_Ve.20$an4.770@news.uswest.net...[color=blue]
> I'm trying to diagnose a p0171 error code.[/color]

P0171 means Bank 1 system too lean.
[color=blue]
>
> I've got an actron obd II scanner from Murray's
>
> alldata's website says:
> 1. install the scan tool
> 2. start and idle engine at normal operating temperature in the Closed
> Loop
> 3. record the data for long term fuel trim
> 4. turn off engine
> 5. turn on ignition, engine off
> 6. review freeze frame / failure records and record displayed data for
> this
> diagnostic trouble code
>
> how do I get it in the Closed Loop?[/color]

Closed Loop means the O2 sensor is heated up to operating temperature and is
providing signals to the ECU. To get it to closed loop, drive the car for
about 5 minutes or so.
[color=blue]
> how do I get the data for long term fuel trim in the scanner?
> how do I view freeze frame / failure records in the scanner?
>
> thanks.
>[/color]

Simple OBD II scanners do not have the capability to provide fuel trim or
freeze frame information.
Scanners with that capability tend to be in the thousands of dollars. The
ones they lend out at auto parts stores are under a hundred dollars.

What kind of vehicle are you trying to diagnose? Are you sure there was
only 1 trouble code? Was there a code for O2 sensor or MAF sensor? A
marginal O2 sensor or MAF sensor can cause this code.
--
Ray O
correct the return address punctuation to reply

so I just warm up my car then to get to the closed loop?

will my scanner tell me if I'm in closed loop?

"TeGGeR®" <tegger@tegger.c0m> wrote in message
news:Xns96D19700883Btegger@207.14.113.17...[color=blue]
> "Raymond" <noemail@noemail.com> wrote in
> news:be_Ve.20$an4.770@news.uswest.net:
>[color=green]
> > I'm trying to diagnose a p0171 error code.
> >
> > I've got an actron obd II scanner from Murray's
> >
> > alldata's website says:
> > 1. install the scan tool
> > 2. start and idle engine at normal operating temperature in the Closed
> > Loop 3. record the data for long term fuel trim
> > 4. turn off engine
> > 5. turn on ignition, engine off
> > 6. review freeze frame / failure records and record displayed data for
> > this diagnostic trouble code
> >
> > how do I get it in the Closed Loop?[/color]
>
>
>
> "Closed-loop" occurs when the ECM sees that the coolant temperature is at
> 90C (194F), and the throttle is NOT wide open.
>
> If the engine is less than full-warm, you run the risk of dropping to[/color]
open-[color=blue]
> loop, which is when the upstream O2 sensor is not used as ECM input.
>
>
> --
> TeGGeR®
>
> The Unofficial Honda/Acura FAQ
> [url]www.tegger.com/hondafaq/[/url]
>[/color]

"Raymond" <noemail@noemail.com> wrote in message
news:lo_Ve.22$an4.779@news.uswest.net...[color=blue]
> so I just warm up my car then to get to the closed loop?[/color]

Yes, but at idle, not with the throttle floored.
[color=blue]
>
> will my scanner tell me if I'm in closed loop?[/color]

Probably not.
--
Ray O
correct the return address punctuation to reply
[color=blue]
>
> "TeGGeR®" <tegger@tegger.c0m> wrote in message
> news:Xns96D19700883Btegger@207.14.113.17...[color=green]
>> "Raymond" <noemail@noemail.com> wrote in
>> news:be_Ve.20$an4.770@news.uswest.net:
>>[color=darkred]
>> > I'm trying to diagnose a p0171 error code.
>> >
>> > I've got an actron obd II scanner from Murray's
>> >
>> > alldata's website says:
>> > 1. install the scan tool
>> > 2. start and idle engine at normal operating temperature in the Closed
>> > Loop 3. record the data for long term fuel trim
>> > 4. turn off engine
>> > 5. turn on ignition, engine off
>> > 6. review freeze frame / failure records and record displayed data for
>> > this diagnostic trouble code
>> >
>> > how do I get it in the Closed Loop?[/color]
>>
>>
>>
>> "Closed-loop" occurs when the ECM sees that the coolant temperature is at
>> 90C (194F), and the throttle is NOT wide open.
>>
>> If the engine is less than full-warm, you run the risk of dropping to[/color]
> open-[color=green]
>> loop, which is when the upstream O2 sensor is not used as ECM input.
>>
>>
>> --
>> TeGGeR®
>>
>> The Unofficial Honda/Acura FAQ
>> [url]www.tegger.com/hondafaq/[/url]
>>[/color]
>
>[/color]

I figure out the bank 1 system too lean.

it's actually for a nissan pathfinder. I've been reading this group for a
while and noticed there are quite a few knowledgeable people around here
that can help me.

I've reset the light 3 times. 1st time, I just got P0171. 2nd time, I got
P0171, bank 2 system too lean. the 3rd time, just P0171.

I looked at the MAF sensor, and it looked ok. no tools to test.

stupid car has 4 oxygen sensors. 2 were already replaced which were by the
catalytic converter. the other 2 are right by the engine. how can I test if
the oxygen sensor is bad?

"Ray O" <rokigawa@tristarassociatesDOT.com> wrote in message
news:c464b$43287351$44a4a10d$27195@msgid.meganewsservers.com...[color=blue]
>
> "Raymond" <noemail@noemail.com> wrote in message
> news:be_Ve.20$an4.770@news.uswest.net...[color=green]
> > I'm trying to diagnose a p0171 error code.[/color]
>
> P0171 means Bank 1 system too lean.
>[color=green]
> >
> > I've got an actron obd II scanner from Murray's
> >
> > alldata's website says:
> > 1. install the scan tool
> > 2. start and idle engine at normal operating temperature in the Closed
> > Loop
> > 3. record the data for long term fuel trim
> > 4. turn off engine
> > 5. turn on ignition, engine off
> > 6. review freeze frame / failure records and record displayed data for
> > this
> > diagnostic trouble code
> >
> > how do I get it in the Closed Loop?[/color]
>
> Closed Loop means the O2 sensor is heated up to operating temperature and[/color]
is[color=blue]
> providing signals to the ECU. To get it to closed loop, drive the car for
> about 5 minutes or so.
>[color=green]
> > how do I get the data for long term fuel trim in the scanner?
> > how do I view freeze frame / failure records in the scanner?
> >
> > thanks.
> >[/color]
>
> Simple OBD II scanners do not have the capability to provide fuel trim or
> freeze frame information.
> Scanners with that capability tend to be in the thousands of dollars. The
> ones they lend out at auto parts stores are under a hundred dollars.
>
> What kind of vehicle are you trying to diagnose? Are you sure there was
> only 1 trouble code? Was there a code for O2 sensor or MAF sensor? A
> marginal O2 sensor or MAF sensor can cause this code.
> --
> Ray O
> correct the return address punctuation to reply
>
>
>[/color]

"Raymond" <noemail@noemail.com> wrote in message
news:MA_Ve.24$an4.829@news.uswest.net...[color=blue]
>I figure out the bank 1 system too lean.
>
> it's actually for a nissan pathfinder. I've been reading this group for a
> while and noticed there are quite a few knowledgeable people around here
> that can help me.
>
> I've reset the light 3 times. 1st time, I just got P0171. 2nd time, I got
> P0171, bank 2 system too lean. the 3rd time, just P0171.
>
> I looked at the MAF sensor, and it looked ok. no tools to test.[/color]

If it is a heated wire system, make sure the wire isn't coated with gunk.
[color=blue]
>
> stupid car has 4 oxygen sensors. 2 were already replaced which were by the
> catalytic converter. the other 2 are right by the engine. how can I test
> if
> the oxygen sensor is bad?[/color]

4 O2 sensors is common on a V6 or V8 engine. A properly functioning O2
sensor in closed loop mode will send an on-off signal to the ECU. You may
try google to see if you can come up with the proper voltage and repetition
rate.
--
Ray O
correct the return address punctuation to reply


[color=blue]
>
> "Ray O" <rokigawa@tristarassociatesDOT.com> wrote in message
> news:c464b$43287351$44a4a10d$27195@msgid.meganewsservers.com...[color=green]
>>
>> "Raymond" <noemail@noemail.com> wrote in message
>> news:be_Ve.20$an4.770@news.uswest.net...[color=darkred]
>> > I'm trying to diagnose a p0171 error code.[/color]
>>
>> P0171 means Bank 1 system too lean.
>>[color=darkred]
>> >
>> > I've got an actron obd II scanner from Murray's
>> >
>> > alldata's website says:
>> > 1. install the scan tool
>> > 2. start and idle engine at normal operating temperature in the Closed
>> > Loop
>> > 3. record the data for long term fuel trim
>> > 4. turn off engine
>> > 5. turn on ignition, engine off
>> > 6. review freeze frame / failure records and record displayed data for
>> > this
>> > diagnostic trouble code
>> >
>> > how do I get it in the Closed Loop?[/color]
>>
>> Closed Loop means the O2 sensor is heated up to operating temperature and[/color]
> is[color=green]
>> providing signals to the ECU. To get it to closed loop, drive the car
>> for
>> about 5 minutes or so.
>>[color=darkred]
>> > how do I get the data for long term fuel trim in the scanner?
>> > how do I view freeze frame / failure records in the scanner?
>> >
>> > thanks.
>> >[/color]
>>
>> Simple OBD II scanners do not have the capability to provide fuel trim or
>> freeze frame information.
>> Scanners with that capability tend to be in the thousands of dollars.
>> The
>> ones they lend out at auto parts stores are under a hundred dollars.
>>
>> What kind of vehicle are you trying to diagnose? Are you sure there was
>> only 1 trouble code? Was there a code for O2 sensor or MAF sensor? A
>> marginal O2 sensor or MAF sensor can cause this code.
>> --
>> Ray O
>> correct the return address punctuation to reply
>>
>>
>>[/color]
>
>[/color]

"Ray O" <rokigawa@tristarassociatesDOT.com> wrote in message[color=blue]
> If it is a heated wire system, make sure the wire isn't coated with gunk.[/color]

it's not a heated wire.it's plastic with some electronics in the middle.
[color=blue]
>[color=green]
> >
> > stupid car has 4 oxygen sensors. 2 were already replaced which were by[/color][/color]
the[color=blue][color=green]
> > catalytic converter. the other 2 are right by the engine. how can I test
> > if
> > the oxygen sensor is bad?[/color]
>
> 4 O2 sensors is common on a V6 or V8 engine. A properly functioning O2
> sensor in closed loop mode will send an on-off signal to the ECU. You may
> try google to see if you can come up with the proper voltage and[/color]
repetition[color=blue]
> rate.[/color]

so can the $150 dollar scanner I have tell me if one of my O2 sensors is
bad?
[color=blue]
> --
> Ray O
> correct the return address punctuation to reply
>
>
>[color=green]
> >
> > "Ray O" <rokigawa@tristarassociatesDOT.com> wrote in message
> > news:c464b$43287351$44a4a10d$27195@msgid.meganewsservers.com...[color=darkred]
> >>
> >> "Raymond" <noemail@noemail.com> wrote in message
> >> news:be_Ve.20$an4.770@news.uswest.net...
> >> > I'm trying to diagnose a p0171 error code.
> >>
> >> P0171 means Bank 1 system too lean.
> >>
> >> >
> >> > I've got an actron obd II scanner from Murray's
> >> >
> >> > alldata's website says:
> >> > 1. install the scan tool
> >> > 2. start and idle engine at normal operating temperature in the[/color][/color][/color]
Closed[color=blue][color=green][color=darkred]
> >> > Loop
> >> > 3. record the data for long term fuel trim
> >> > 4. turn off engine
> >> > 5. turn on ignition, engine off
> >> > 6. review freeze frame / failure records and record displayed data[/color][/color][/color]
for[color=blue][color=green][color=darkred]
> >> > this
> >> > diagnostic trouble code
> >> >
> >> > how do I get it in the Closed Loop?
> >>
> >> Closed Loop means the O2 sensor is heated up to operating temperature[/color][/color][/color]
and[color=blue][color=green]
> > is[color=darkred]
> >> providing signals to the ECU. To get it to closed loop, drive the car
> >> for
> >> about 5 minutes or so.
> >>
> >> > how do I get the data for long term fuel trim in the scanner?
> >> > how do I view freeze frame / failure records in the scanner?
> >> >
> >> > thanks.
> >> >
> >>
> >> Simple OBD II scanners do not have the capability to provide fuel trim[/color][/color][/color]
or[color=blue][color=green][color=darkred]
> >> freeze frame information.
> >> Scanners with that capability tend to be in the thousands of dollars.
> >> The
> >> ones they lend out at auto parts stores are under a hundred dollars.
> >>
> >> What kind of vehicle are you trying to diagnose? Are you sure there[/color][/color][/color]
was[color=blue][color=green][color=darkred]
> >> only 1 trouble code? Was there a code for O2 sensor or MAF sensor? A
> >> marginal O2 sensor or MAF sensor can cause this code.
> >> --
> >> Ray O
> >> correct the return address punctuation to reply
> >>
> >>
> >>[/color]
> >
> >[/color]
>
>
>[/color]

"Raymond" <noemail@noemail.com> wrote in message
news:wy%Ve.30$an4.875@news.uswest.net...[color=blue]
> "Ray O" <rokigawa@tristarassociatesDOT.com> wrote in message[color=green]
>> If it is a heated wire system, make sure the wire isn't coated with gunk.[/color]
>
> it's not a heated wire.it's plastic with some electronics in the middle.[/color]

I'm not familiar with Nissan so I'd have to look at it to see how it works.
There are basically 3 ways to measure how much air is getting into the
engine:
1) A mechanical flap or vane that moves more as more air flows past it.
2) A heated wire that gets cooled more as more air flows past it.
3) An optical system that is kins of like those burglar alarms that shine a
light at a target. The light is reflected off a mirror that is mounted on a
filament in the air stream. The more air flows, the more the filament and
mirror are disturbed and so the light detector counts the disturbances.
[color=blue]
>[color=green]
>>[color=darkred]
>> >
>> > stupid car has 4 oxygen sensors. 2 were already replaced which were by[/color][/color]
> the[color=green][color=darkred]
>> > catalytic converter. the other 2 are right by the engine. how can I
>> > test
>> > if
>> > the oxygen sensor is bad?[/color]
>>
>> 4 O2 sensors is common on a V6 or V8 engine. A properly functioning O2
>> sensor in closed loop mode will send an on-off signal to the ECU. You
>> may
>> try google to see if you can come up with the proper voltage and[/color]
> repetition[color=green]
>> rate.[/color]
>
> so can the $150 dollar scanner I have tell me if one of my O2 sensors is
> bad?
>[/color]

Yes and no. The scan tool will know if the O2 sensor is inoperative or has
an open or short circuit but it won't tell if the O2 sensor's performance is
marginal, especially if it is like the Actron scan tool I have. You'll need
a digital volt/ohm meter for that.

--
Ray O
correct the return address punctuation to reply
[color=blue][color=green]
>> --
>> Ray O
>> correct the return address punctuation to reply
>>
>>
>>[color=darkred]
>> >
>> > "Ray O" <rokigawa@tristarassociatesDOT.com> wrote in message
>> > news:c464b$43287351$44a4a10d$27195@msgid.meganewsservers.com...
>> >>
>> >> "Raymond" <noemail@noemail.com> wrote in message
>> >> news:be_Ve.20$an4.770@news.uswest.net...
>> >> > I'm trying to diagnose a p0171 error code.
>> >>
>> >> P0171 means Bank 1 system too lean.
>> >>
>> >> >
>> >> > I've got an actron obd II scanner from Murray's
>> >> >
>> >> > alldata's website says:
>> >> > 1. install the scan tool
>> >> > 2. start and idle engine at normal operating temperature in the[/color][/color]
> Closed[color=green][color=darkred]
>> >> > Loop
>> >> > 3. record the data for long term fuel trim
>> >> > 4. turn off engine
>> >> > 5. turn on ignition, engine off
>> >> > 6. review freeze frame / failure records and record displayed data[/color][/color]
> for[color=green][color=darkred]
>> >> > this
>> >> > diagnostic trouble code
>> >> >
>> >> > how do I get it in the Closed Loop?
>> >>
>> >> Closed Loop means the O2 sensor is heated up to operating temperature[/color][/color]
> and[color=green][color=darkred]
>> > is
>> >> providing signals to the ECU. To get it to closed loop, drive the car
>> >> for
>> >> about 5 minutes or so.
>> >>
>> >> > how do I get the data for long term fuel trim in the scanner?
>> >> > how do I view freeze frame / failure records in the scanner?
>> >> >
>> >> > thanks.
>> >> >
>> >>
>> >> Simple OBD II scanners do not have the capability to provide fuel trim[/color][/color]
> or[color=green][color=darkred]
>> >> freeze frame information.
>> >> Scanners with that capability tend to be in the thousands of dollars.
>> >> The
>> >> ones they lend out at auto parts stores are under a hundred dollars.
>> >>
>> >> What kind of vehicle are you trying to diagnose? Are you sure there[/color][/color]
> was[color=green][color=darkred]
>> >> only 1 trouble code? Was there a code for O2 sensor or MAF sensor? A
>> >> marginal O2 sensor or MAF sensor can cause this code.
>> >> --
>> >> Ray O
>> >> correct the return address punctuation to reply
>> >>
>> >>
>> >>
>> >
>> >[/color]
>>
>>
>>[/color]
>
>[/color]

Geez, what a pain. I don't know what sort of tool you're working with, but
to diagnose this you will need the capability to access the 'data list'
from the computer. If you are using a scanner that just serves as a code
reader, than that won't cut it.
Anyway, the reason you need to see the data list is to observe fuel trim
#s, and also the input voltages from the 02 sensors. But, barring an
expensive scanner, you could observe the voltage of the sensor directly
from the sensor with a good meter or logging scope. I've had to do that a
few times, and it works. The sensors cycle between .2v (lean) to
8v(rich), but the frequency varies from manufacturer to manufacturer.

"Ray O" <rokigawa@tristarassociatesDOT.com> wrote in message
news:a8619$432887e4$44a4a10d$28101@msgid.meganewsservers.com...[color=blue]
>
> "Raymond" <noemail@noemail.com> wrote in message
> news:wy%Ve.30$an4.875@news.uswest.net...[color=green]
> > "Ray O" <rokigawa@tristarassociatesDOT.com> wrote in message[color=darkred]
> >> If it is a heated wire system, make sure the wire isn't coated with[/color][/color][/color]
gunk.[color=blue][color=green]
> >
> > it's not a heated wire.it's plastic with some electronics in the middle.[/color]
>
> I'm not familiar with Nissan so I'd have to look at it to see how it[/color]
works.[color=blue]
> There are basically 3 ways to measure how much air is getting into the
> engine:
> 1) A mechanical flap or vane that moves more as more air flows past it.
> 2) A heated wire that gets cooled more as more air flows past it.
> 3) An optical system that is kins of like those burglar alarms that shine[/color]
a[color=blue]
> light at a target. The light is reflected off a mirror that is mounted on[/color]
a[color=blue]
> filament in the air stream. The more air flows, the more the filament and
> mirror are disturbed and so the light detector counts the disturbances.
>[/color]
I think what I have is the optical system.[color=blue][color=green][color=darkred]
> >> >
> >> > stupid car has 4 oxygen sensors. 2 were already replaced which were[/color][/color][/color]
by[color=blue][color=green]
> > the[color=darkred]
> >> > catalytic converter. the other 2 are right by the engine. how can I
> >> > test
> >> > if
> >> > the oxygen sensor is bad?
> >>
> >> 4 O2 sensors is common on a V6 or V8 engine. A properly functioning O2
> >> sensor in closed loop mode will send an on-off signal to the ECU. You
> >> may
> >> try google to see if you can come up with the proper voltage and[/color]
> > repetition[color=darkred]
> >> rate.[/color]
> >
> > so can the $150 dollar scanner I have tell me if one of my O2 sensors is
> > bad?
> >[/color]
>
> Yes and no. The scan tool will know if the O2 sensor is inoperative or[/color]
has[color=blue]
> an open or short circuit but it won't tell if the O2 sensor's performance[/color]
is[color=blue]
> marginal, especially if it is like the Actron scan tool I have. You'll[/color]
need[color=blue]
> a digital volt/ohm meter for that.[/color]

I guess if I have problems with my O2 sensors, looks like the performance
are marginal? If I get lucky, will it will me which O2 sensor it is?

If not, I guess I'm stuck to bringing it to a mechanic.
[color=blue]
> --
> Ray O
> correct the return address punctuation to reply
>[color=green][color=darkred]
> >> --
> >> Ray O
> >> correct the return address punctuation to reply
> >>
> >>
> >>
> >> >
> >> > "Ray O" <rokigawa@tristarassociatesDOT.com> wrote in message
> >> > news:c464b$43287351$44a4a10d$27195@msgid.meganewsservers.com...
> >> >>
> >> >> "Raymond" <noemail@noemail.com> wrote in message
> >> >> news:be_Ve.20$an4.770@news.uswest.net...
> >> >> > I'm trying to diagnose a p0171 error code.
> >> >>
> >> >> P0171 means Bank 1 system too lean.
> >> >>
> >> >> >
> >> >> > I've got an actron obd II scanner from Murray's
> >> >> >
> >> >> > alldata's website says:
> >> >> > 1. install the scan tool
> >> >> > 2. start and idle engine at normal operating temperature in the[/color]
> > Closed[color=darkred]
> >> >> > Loop
> >> >> > 3. record the data for long term fuel trim
> >> >> > 4. turn off engine
> >> >> > 5. turn on ignition, engine off
> >> >> > 6. review freeze frame / failure records and record displayed data[/color]
> > for[color=darkred]
> >> >> > this
> >> >> > diagnostic trouble code
> >> >> >
> >> >> > how do I get it in the Closed Loop?
> >> >>
> >> >> Closed Loop means the O2 sensor is heated up to operating[/color][/color][/color]
temperature[color=blue][color=green]
> > and[color=darkred]
> >> > is
> >> >> providing signals to the ECU. To get it to closed loop, drive the[/color][/color][/color]
car[color=blue][color=green][color=darkred]
> >> >> for
> >> >> about 5 minutes or so.
> >> >>
> >> >> > how do I get the data for long term fuel trim in the scanner?
> >> >> > how do I view freeze frame / failure records in the scanner?
> >> >> >
> >> >> > thanks.
> >> >> >
> >> >>
> >> >> Simple OBD II scanners do not have the capability to provide fuel[/color][/color][/color]
trim[color=blue][color=green]
> > or[color=darkred]
> >> >> freeze frame information.
> >> >> Scanners with that capability tend to be in the thousands of[/color][/color][/color]
dollars.[color=blue][color=green][color=darkred]
> >> >> The
> >> >> ones they lend out at auto parts stores are under a hundred dollars.
> >> >>
> >> >> What kind of vehicle are you trying to diagnose? Are you sure there[/color]
> > was[color=darkred]
> >> >> only 1 trouble code? Was there a code for O2 sensor or MAF sensor?[/color][/color][/color]
A[color=blue][color=green][color=darkred]
> >> >> marginal O2 sensor or MAF sensor can cause this code.
> >> >> --
> >> >> Ray O
> >> >> correct the return address punctuation to reply
> >> >>
> >> >>
> >> >>
> >> >
> >> >
> >>
> >>
> >>[/color]
> >
> >[/color]
>
>
>[/color]

"Raymond" <noemail@noemail.com> wrote in message
news:FX%Ve.33$an4.870@news.uswest.net...

<snipped>
[color=blue][color=green][color=darkred]
>> >> 4 O2 sensors is common on a V6 or V8 engine. A properly functioning
>> >> O2
>> >> sensor in closed loop mode will send an on-off signal to the ECU. You
>> >> may
>> >> try google to see if you can come up with the proper voltage and
>> > repetition
>> >> rate.
>> >
>> > so can the $150 dollar scanner I have tell me if one of my O2 sensors
>> > is
>> > bad?
>> >[/color]
>>
>> Yes and no. The scan tool will know if the O2 sensor is inoperative or[/color]
> has[color=green]
>> an open or short circuit but it won't tell if the O2 sensor's performance[/color]
> is[color=green]
>> marginal, especially if it is like the Actron scan tool I have. You'll[/color]
> need[color=green]
>> a digital volt/ohm meter for that.[/color]
>
> I guess if I have problems with my O2 sensors, looks like the performance
> are marginal?[/color]

If the O2 sensor quit working altogether, you would have a trouble code for
it. An O2 sensor that is getting ready to fail might not set a trouble
code.

If I get lucky, will it will me which O2 sensor it is?

If the O2 sensor fails altogether, the scan tool will tell you by the code,
i.e. bank 1 sensor 1or bank 1 sensor 2 or bank 2 sensor 1 or bank 2 sensor
2. If the O2 sensor hasn't completely failed, then you're out of luck.
[color=blue]
>
> If not, I guess I'm stuck to bringing it to a mechanic.
>[/color]

If you invested in a scan tool, you might want to invest in a basic digital
volt/ohm meter. You can get one at an electronics shop like Radio Shack for
under $50. Then do a google search on measuring O2 sensor performance and
you can tell for sure.


--
Ray O
correct the return address punctuation to reply

it's actually a loaner tool from an auto parts store.

the two O2 sensors, if they're the ones that are bad, are a bit difficult to
get to.

I guess I'll take it to a mechanic.

thanks for all your help.

"Ray O" <rokigawa@tristarassociatesDOT.com> wrote in message
news:8b1bc$43288de6$44a4a10d$28330@msgid.meganewsservers.com...[color=blue]
>
> "Raymond" <noemail@noemail.com> wrote in message
> news:FX%Ve.33$an4.870@news.uswest.net...
>
> <snipped>
>[color=green][color=darkred]
> >> >> 4 O2 sensors is common on a V6 or V8 engine. A properly functioning
> >> >> O2
> >> >> sensor in closed loop mode will send an on-off signal to the ECU.[/color][/color][/color]
You[color=blue][color=green][color=darkred]
> >> >> may
> >> >> try google to see if you can come up with the proper voltage and
> >> > repetition
> >> >> rate.
> >> >
> >> > so can the $150 dollar scanner I have tell me if one of my O2 sensors
> >> > is
> >> > bad?
> >> >
> >>
> >> Yes and no. The scan tool will know if the O2 sensor is inoperative or[/color]
> > has[color=darkred]
> >> an open or short circuit but it won't tell if the O2 sensor's[/color][/color][/color]
performance[color=blue][color=green]
> > is[color=darkred]
> >> marginal, especially if it is like the Actron scan tool I have. You'll[/color]
> > need[color=darkred]
> >> a digital volt/ohm meter for that.[/color]
> >
> > I guess if I have problems with my O2 sensors, looks like the[/color][/color]
performance[color=blue][color=green]
> > are marginal?[/color]
>
> If the O2 sensor quit working altogether, you would have a trouble code[/color]
for[color=blue]
> it. An O2 sensor that is getting ready to fail might not set a trouble
> code.
>
> If I get lucky, will it will me which O2 sensor it is?
>
> If the O2 sensor fails altogether, the scan tool will tell you by the[/color]
code,[color=blue]
> i.e. bank 1 sensor 1or bank 1 sensor 2 or bank 2 sensor 1 or bank 2 sensor
> 2. If the O2 sensor hasn't completely failed, then you're out of luck.
>[color=green]
> >
> > If not, I guess I'm stuck to bringing it to a mechanic.
> >[/color]
>
> If you invested in a scan tool, you might want to invest in a basic[/color]
digital[color=blue]
> volt/ohm meter. You can get one at an electronics shop like Radio Shack[/color]
for[color=blue]
> under $50. Then do a google search on measuring O2 sensor performance and
> you can tell for sure.
>
>
> --
> Ray O
> correct the return address punctuation to reply
>
>
>[/color]

"Raymond" <noemail@noemail.com> wrote in message
news:eQ0We.38$an4.341@news.uswest.net...[color=blue]
> it's actually a loaner tool from an auto parts store.
>
> the two O2 sensors, if they're the ones that are bad, are a bit difficult
> to
> get to.
>
> I guess I'll take it to a mechanic.
>
> thanks for all your help.[/color]

You're welcome!

Good luck.
--
Ray O
correct the return address punctuation to reply

"Ray O" <rokigawa@tristarassociatesDOT.com> wrote in
news:a8619$432887e4$44a4a10d$28101@msgid.meganewsservers.com:
[color=blue]
>
> "Raymond" <noemail@noemail.com> wrote in message
> news:wy%Ve.30$an4.875@news.uswest.net...[color=green]
>> "Ray O" <rokigawa@tristarassociatesDOT.com> wrote in message[color=darkred]
>>> If it is a heated wire system, make sure the wire isn't coated with
>>> gunk.[/color]
>>
>> it's not a heated wire.it's plastic with some electronics in the
>> middle.[/color]
>
> I'm not familiar with Nissan so I'd have to look at it to see how it
> works. There are basically 3 ways to measure how much air is getting
> into the engine:
> 1) A mechanical flap or vane that moves more as more air flows past
> it. 2) A heated wire that gets cooled more as more air flows past it.
> 3) An optical system that is kins of like those burglar alarms that
> shine a light at a target. The light is reflected off a mirror that
> is mounted on a filament in the air stream. The more air flows, the
> more the filament and mirror are disturbed and so the light detector
> counts the disturbances.[/color]


The latest method is TFT, which is exactly as the OP describes it.
Apparently that's less prone to contamination than the other methods.

More here:
[url]http://www.4x4wire.com/toyota/4Runner/tech/OBDII_ECU/[/url]
This may help the OP determine the cause of his problem.


--
TeGGeR®

The Unofficial Honda/Acura FAQ
[url]www.tegger.com/hondafaq/[/url]