From: Sarah Houston on
"Ray O" <rokigawa(a)NOSPAMtristarassociates.com> wrote :

>
> "Sarah Houston" <SHoust(a)pndfnospam.com> wrote in message
> news:Xns9B741054FA82ASntzldfrdSntzldfrdco(a)216.196.97.142...
><snipped>>
>>
>> Well the MPG hasn't been so great this past year or so.
>>
>
> Keep in mind that on a 5 year old vehicle operated where salt is used
> on roads, the O2 sensor may be rusted in place. Hopefully, this
> won't be the case, but be prepared to replace the exhaust manifold as
> well (probably an extra $300 or so) if it strips when removing the
> old sensor.

The manifold was replaced a few months ago, due to a big crack in it.


From: Ray O on

"Sarah Houston" <SHoust(a)pndfnospam.com> wrote in message
news:Xns9B74A2500D73SntzldfrdSntzldfrdco(a)216.196.97.142...
> "Ray O" <rokigawa(a)NOSPAMtristarassociates.com> wrote :
>
>>
>> "Sarah Houston" <SHoust(a)pndfnospam.com> wrote in message
>> news:Xns9B741054FA82ASntzldfrdSntzldfrdco(a)216.196.97.142...
>><snipped>>
>>>
>>> Well the MPG hasn't been so great this past year or so.
>>>
>>
>> Keep in mind that on a 5 year old vehicle operated where salt is used
>> on roads, the O2 sensor may be rusted in place. Hopefully, this
>> won't be the case, but be prepared to replace the exhaust manifold as
>> well (probably an extra $300 or so) if it strips when removing the
>> old sensor.
>
> The manifold was replaced a few months ago, due to a big crack in it.
>
>
That's when you should have installed a new O2 sensor, rather than spending
time trying to get the old one out. You should check the repair order to
see if a new one was installed at that time.
--

Ray O
(correct punctuation to reply)


From: Sarah Houston on
=?iso-2022-jp?q?Hachiroku_=1B$B%O%A%m%=2F=1B=28B?= <Trueno(a)e86.GTS>
wrote :

> On Sat, 13 Dec 2008 22:43:26 -0600, Ray O wrote:
>
>> I have heard of problems when people use non-OEM sensors on Toyotas,
>> but Bosch should be OK to use if you use the one with the correct
>> factory connector. Some of the cheaper O2 sensors do not have the
>> correct factory connector and you have to splice wires. The splices
>> often end up being short-lived and you end up with problems within a
>> year or so.
>
> I replaced the O2 sensors in my Tercel with Bosch sensors. They are
> probably the best AM sensors you can get, if you can't get Denso.
> Also, I was working at a CarQuest when I did it, so I paid about $35
> each for them.
>
> And, when *I* do splices, they *STAY* spliced! ;)
>
> I had no problems with them. Fuel economy and performance actually
> increased, probably mainly for the reason they were new.

Well someone here awhile back, was saying that they get clogged after
awhile, so the resistance wouldn't matter that much then, eh?

I wonder what additives like BG44k do to them?

Seems like I was briefly getting better MPG when the tank had that in
it.


From: Sarah Houston on
=?iso-2022-jp?q?Hachiroku_=1B$B%O%A%m%=2F=1B=28B?= <Trueno(a)e86.GTS> wrote
:

> On Sun, 14 Dec 2008 00:46:06 -0600, Sarah Houston wrote:
>
>>
>> After doing some extensive reading, it began to come clear how the O2
>> Sensor performance could be off, yet not be able to see any symptoms
>> (other than lower gas mileage) with the tools I was using.
>
> Hmmm...are you really a girl?

I didn't write that, it was at that site.

> Where are you?
> Can you replace transmissions and U-joints? ;)

No, about all I do is my own plugs, dist caps, the easy top side stuff.

Don't even mess with my own oil changes.

From: Sarah Houston on
"larry moe 'n curly" <larrymoencurly(a)my-deja.com> wrote :

> Sarah Houston wrote:
>
>> After doing some extensive reading, it began to come clear how the O2
>> Sensor performance could be off, yet not be able to see any symptoms
>> (other than lower gas mileage) with the tools I was using. It turns
out
>> that the O2 swing cycle shown in the photographs is the swing time of
>> the overall system and not just the O2 sensor itself. To really
examine
>> the performance the O2 sensor, for example to determine if it was
>> developing a lean or rich offset, one would have to use a digital
volt
>> meter with an averaging feature connected directly to the sensor and
>> look for the 450mV centerline signal in a known, properly performing
>> system centered at the 50% duty cycle.
>
> Are there digital voltage meters that don't average semi-fast
> signals? I think for testing O2 sensors, a meter with a fast-reacting
> bar graph would be better.
>
>> To measure responsiveness, one would have to use a laboratory scope
>
> Why? It's just a low frequency signal that any regular scope, or even
> a cheapo handheld 1 MHz scope/DVM can display.
>
> Do any owner's manuals mention a replacement interval for the O2
> sensors, that is, for vehicles made since the mid-1980s?
>

I googled and found:

http://www.autohausaz.com/html/emissions-oxygen_sensors.html

Oxygen Sensors Don't Last Forever
Here's What Happens As They Age

As an oxygen sensor ages, contaminants from normal combustion and oil
ash accumulate on the sensing element. This reduces the sensor's ability
to respond quickly to changes in the air/fuel mixture. The sensor slows
down and becomes "sluggish".

At the same time, the sensor's output voltage may not be as high as it
once was, giving the false impression that the air/fuel mixture is
leaner than it actually is. The result can be a richer-than-normal
air/fuel mixture under various operating conditions that causes fuel
consumption and emissions to rise.

The problem may not be noticed right away because the change in
performance occurs gradually. But, over time, the situation will get
worse, ultimately requiring the sensor to be replaced to restore peak
engine performance.
....

Don't Wait For Failure
Replace Your Oxygen Sensor as Normal Preventive Maintenance

To minimize the consequences of normal aging, Bosch recommends oxygen
sensor replacement for preventive maintenance at the following
intervals:
Type of Car

Mileage Replacement Interval Recommended
Unheated oxygen sensors on 1976 to early 1990s vehicles
Every 30,000 - 50,000 miles

Heated (1st generation) oxygen sensors on mid-1980s to mid-1990s
vehicles
Every 60,000 miles

Heated (2nd generation) oxygen sensors on mid-1990s and newer vehicles
Every 100,000 miles
_________

I'm not sure what the 93 7AFE has, does anyone know?

I can just look under the hood...

when the weather warms a little, it's -1 here in west Denver right now.