O2 Sensor.. Alert ! ..and new info
 

Guys:
I've had a lengthy exchange with a rep from Bosch-USA on
the various types of O2 sensors. My primary concern was trying to get
economic alternatives to the very expensive Porsche ( Bosch) units, as well
as understand the various differences that might exist..and also if there
are any caveats. Some interesting things came out of our discussions.
Summary follows:
- the various O2 sensors pretty much act the same way, in terms
of output signal vs input readings, however...
- there are various ceramic types, and for the three-wire
heated systems , various heater strengths ( 12W and 18W)
- for the mid 80's , 3.2L Carrera's, using DME control... you
may substitute:
Bosch 13913, 3 wire unit originally intended for
Ford applications. I believe this has an 8" lead, and you must splice -in
the original Porsche connectors ( more on splicing caveats later).
Bosch 13953, similar 3 wire unit for Fords, but
with ( I believe) 16" long connectors.
Bosch 15725, Bosch "universal" , with universal
connector kit that avoids certain problems compared to using generic
connectors ( again, more later).
Bosch 15726... an alternative to 15725....also OK
to use for 3.2L Carreras.
Bosch 15715, 4 wire .. NOT OK to use ( more on 4
wire later).
By the way , the "long" and "short" Bosch part numbers relate as
follows. The short number ( ex. 15725) is the last 4 digits of the long
number with a "1" in front of it ( long number .... 0258005725 ).

Anyway, here's what I found VERY interesting. The O2 sensor works on
the principle of comparison signals, and the reference signal is "local"
oxygen that is not in the exhaust stream. These sensors are located in
harsh environments, so the reference O2 signal is transmitted UNDER THE
WIRE INSULATION ...back to the computer....via the engine compartment
(sealed) connector. The CAVEAT is that if you use a normal crimp connector
( to re-use the Porsche plugs, for example) you might introduce engine
compartment "air" unknowingly as the reference signal. This can be bad.
Furthermore, I usually use the marine-grade connectors when making
electrical mods to my car. These have a glue inside the crimp, so when you
apply heat to seal the crimped-ends, the glue flows to make a water-tight
seal. Normally, this is good, but in THIS case, it would seal-off the
air-path back to the computer, and compromise the air ( oxygen) reference
signal. WOW ! ... who would have thought about this ??? Bosch's generic
connectors used with the generic units overcome this...by design.
Lastly, I inquired about the use of 4 -wire sensors...thinking the
additional ground would be a "good thing"...much like the upgrade we do on
the cylinder head temp sensors ( later 2 wire temp sensor versions have an
additional ground). The 3-wire O2 sensors use 2 leads for the heater (
non-critical as to hook-up... bi-directional) , and the third lead is the
actual connection / air source. The fourth wire would be the ground. My
thinking thatg since the O2 sensor works as a switch between 0 and 0.1
Volts...a rather low voltage.... an additional ground would be nice.
Instead, I was advised that this additional ground, ( for the same
reason...low voltage operation) may be unduly influenced for stray signal
noise. We were advised to stick with the 3 wire design.
Hope this helps someone...esprcially the new-found info in splicing
caveats !

Wil Ferch
85 Carrera :D

Will, I may be all wrong here but, the electric signal generated by the sensor certainly travels through a wire under the insulation but the difference signal is generated entirely inside the O₂ sensor body.

Here's a detail of the operational portion of a typical sensor
http://www.flash.net/~lorint/lorin/fuel/lambda.jpg

Here is a cross section of a typical O₂
http://www.insightcentral.net/enoldsensor.jpg

Here is the simplified Bosch diagram
http://www.boschusa.com/images/busin...f4_graphic.gif

The 3^rd wire would just be for the heater +

Here is a link to an SAE paper devoted to the Bosch O₂ sensors SAE on Bosch

This is great information Wil. And very timely for me. After having just been bitten by bad reference sensors on my `87 3.2L I'm very sensitive to anything else that may need attention. My 02 sensor is ~56K miles old and I've been searching for an alternative to the $200+ Porsche part. And at the same time a little bit leary of the all too often used statement generic Bosch 02 sensor. I'm still not sure why you can't get Bosch OEM 02 sensors with the Porsche correct connector on it, unless Porsche has some guy in the factory making them up.

Thanks,
John:)

Bill:
What can I say except:
-- don't shoot the messenger. That is emphatically what the Bosch Technical rep says happens. He went on to say that indeed there is air ( O2) in the sensor itself, just as you show in your references and illustrations, ...but that the replenishment supply is as I had indicated , (through the wires back to the computer, ..all of which I found amazing), ..and as he himself desribed. I know he frequents this list and the Rennlist board , and he may wish to chime-in himself...
--- Wil Ferch

I believe that the reference air enters the sensor thru the same opening as the 3 wires. The sheath for the wires stops a few mm shy of the sensor insulator providing an ideal point of entry. The newest sensors actually have some sort of pumping device.

By the way we use the 'Anchor' waterproof connectors w/ tinned copper & brass connectors, shrink wrap & glue everywhere on our boats. Never had a failure or problem. I also use and highly recommend them whenever I do wiring on my cars. I also recommend the use of tinned wire where ever possible.

Bill:
Just so you don't think I'm singling you out to pick on...it was an old (Rennlist) post of yours that I've always valued and archived that lead me to the Ancor connectors in the first place.

Fine stuff.

But...believe what you will. The O2 sensor seems to have an on-board capsule of air, but the BOSCH TECH REP ..says the air communication is maintained to this chamber by the air path under the wire insulation. At first, I didn't believe this either, and I asked about the plug connector in the engine compartment..surely it is not sealed and also can be a source of air ..contaminated air. He emphatically says, "NO"..it is sealed and the air path continues to the computer under your seat. Don't know how else to answer that you "feel" this is incorrect. I would welcome counter-views backed up in some way...like someone maybe taking these things totally apart and then saying the the Rep is wrong.... "full of it"...or somesuch...wouldn't you agree?? As it is, how can we dismiss what the manufacturer says is correct? SmileWavy
---Wil Ferch

Wil: Any thoughts on soldering the splice, and then using heat shrink tubing for insulation?

Yep:
Soldering the splice and then using heat shrink would work, also confirmed by the same discussion with the Bosch rep. The universal kit with its connectors supposedly works, too.

Even as this is debated...these two ways seem to be reasonble ways to go..and would satisfy everybody, those who believe the rep, and those who do not.

--Wil Ferch

I could see where the sheath that protects the wires from the sensor could feed the reference air to the sensor but that sheath ends at the rubber grommet that goes through the engine tin. The wires leave the sheath and go through the grommet as three individual wires.
-Chris

Chris:
Hello again...
The wire we're talking about is the main connector, not the two other leads for the heater nor the sheath that surrounds all these. The main connector apparantly has "communication" with the sensor itself...in the from of connecting to the air chamber within the sensor...as best as I can tell.

Don't understand all the push-back. A factory rep says its so.....and I post that summary here... to help avoid unwanted troubles if spliced wrong. Accordingly, two splicing methods were later given that work..if you believe this air-communication thing or not.....

With that, what more do we need? For all those that don't wish to believe this, and need more info, maybe they can contact Bosch -USA directly as I did..and continue the dialogue there.
---Wil Ferch:confused:

Perhaps I don't completely understand, but it sounds like gibberish to me. If this were true, then an adapter to go from the generic units to the wire harness wouldn't work? I find that very difficult to believe. The connector is just that - an electrical connector. If you have an adapter, and the 02 sensor is outputing the correct values, then you should have correct results.

How much is the generic sensor?

-Wayne

Hmm, I don't understand it. The universal one is about $20-$30 retail!

So, would a small *electrical* adapter work? I don't believe that the rep is correct - the air path doesn't continue back to the computer. The electrical path does, but the wire harness of the 911 contains nothing special like a sealed air chamber. That just sounds rediculous to me.

Of course, I have been known to be wrong before, but I'll bet $100 this time I'm not...

-Wayne

Reference air passing through the sheath of the wires??!! The plug and boot being part of a controlled air path to the computer??!!! What next, am I gonna hear about a controlled oxygen tank enclosed with the Motronic box? ROTFLOL!! I wasn't gonna say anything in this thread, but I cannot resist. I gotta agree with Wayne on this one. Sounds like a Bosch sales rep stroking you with information he has no idea about. Let's see, I've got an an old Carrera 02 sensor in front of me and it looks nothing more special than three wires covered in a irradiated PVC jacket entering the body of the sensor through a simple rubber grommet with three holes in it. Doesn't look any more airtight than my doors are when I shut it. I'm sure you guys here are no dummies, I as a former engineer would like to grill this sales rep, ahem, I mean "tech", on his technical explanations of this just for laughs. He does frequent these boards right? Bad information has got to be worse than no information.

I looked at mine today. The sheath is open right where the wires go into the sensor, and right before the connectors. It looks like it just keeps the wires bundled together - nothing fancy. There's certainly no way in Phoenix that air is gonna make it all the way back to the computer! I've seen vaccum guage setups, with a thin, hard plastic tube from the engine to the guage - that's what you'd need in this case. Otherwise the slightest kink would choke it off.

I bought a universal one last week from another supplier (sorry Wayne, but you didn't have the universal one on the site). The guy told me that they have a shop also, and they always use the universal one unless the customer specifies the specific Porsche model. The black wire goes to the black wire on the connector, and the two white wires are the heating circuit and are interchangeable. I was advised to solder and heat shrink the connections.

Gee:
Maybe being advised to solder and heat shrink has some merit, re: the O2 path thread ???
Starting from basics....the O2 sensor works like a battery, and it needs a reference signal ...air ( O2)...to compare to the value seen within the exhaust stream. Listen carefully to what the TECHNICAL rep says. The body has an encapsualted chamber that has the air. It has an open path NOT to the outside at the body, otherwise road slush and such , ..and water.. might find it's way into that chamber , rendering it useless. Maybe the seal IS imperfect, but if you think about it, that internal air chamber having an air "path" underneath the insulation ...( not the protective SHEATh...where did THAT come from ??)...means simply that any replenishment air can be re-supplied from the source at the DME. Weird...but not without some rationale.
At this point...as I said...I would hope this frequent contributor from Bosch...who has already corrected a number of misconceptions on O2 sensors for the 944 guys...chimes in. It would be nice to get to the bottom of this, on a factual basis...

-Wil Ferch

Same here. As a matter of fact, on the enclosed instruction sheet, it said to solder and heat shrink the new lead to the existing lead. A small piece of heat shrink was even included with the sensor. The sensor was a Bosch, intended for CIS cars.

It's beyond me how any significant amount of air is going to travel up a wire under tight insulation. Perhaps we are about to see the birth of a new urban myth.....the O2 sensor that breathes.

What if the reference side does not need to breathe? ;) ;)
What if the reference side does not "use-up" any O2? . . .and yet some tech guy assumes it must ? ? ?

i've always assumed that the "readings" would come from inside the sensor only. if the wire picked up oxygen from the wire itself whould it not also read it inside the computer from where this wire connects in the computer? i think you may have misunderstood what he was explaining, but this is my opinion.

also, ANY electrical connection creates resistance, this is most likely why they suggest "splice and solder", this method will create the least resistance as opposed to crimps and others.

great thread guys:D

Hi:
With all due respect..I did not misunderstand what the rep said, because it sounded so improbable at first to me too. Reference signal should be "local atmosphere"..if it were in the body of the sensor, ..(as it actaully is).....and if the "opening" of the chamber is "open" to the computer under the seat....what's the difference? It won't be contaminated by water or mud or other nasty efflua...it would be a "representative local oxygen sample". It should be the same under the seat as it is in an enclosed chamber that is perfectly sealed.

I guess whether we believe this or not...it can't be argued that it is good practice to either:
1.) use the universal connectors that come with the universal sensor, or...
2.) Solder, then heat shrink, when using the Ford pieces, and using our old connectors. Why risk a problem by using the marine connectors with glue?

Isn't this a reasonable compromise ??:confused:

--- Wil Ferch

Wil, you should be a mediator. Maybe baseball can use your services. Well done! http://www.pelicanparts.com/support/smileys/clap.gif

Wil,
The person you probably spoke with was a sales rep. I think the answer from a tech. rep would be different (and probably more correct).

BTW, not to take anything away from Wayne's store, but Sumitt Racing sells a 4-wire replacement sensor for about $50.

Sherwood Lee
http://member.rennlist.org/911pcars

I can see that no one bothered to check the link I provided. Oh well, here's the relevant text;

"Sensor design
The oxygen sensor (see Figure 3)is a galvanic oxygen concentration cell with a solid state electrolyte. The solid state electrolyte is an impermeable zirconium dioxide ceramic unit stabilized with yttrium oxide. It is open on one end and closed on the other. Mounted on both the inner and outer surfaces are gas permeable platinum electrodes. The platinum electrode on the outside acts as a miniature catalyst to support reactions in the incoming exhaust gases and bring them into a state of stoichiometric balance. The side that is exposed to the exhaust gases also has a porous ceramic layer (Spinell coating) to protect against contamination. A metal tube with numerous slots guards the ceramic body against impacts and thermal shocks. The inner cavity is open to the atmosphere which serves as the unit’s reference gas. The two-state sensor operation is based in the Nernst Principle. The sensor’s ceramic material conducts oxygen ions at temperatures 350oC and above. Disparities in oxygen levels on the respective sides of the sensor will result in the generation of electrical voltage between the two surfaces. This voltage serves as the index of how much the oxygen levels vary on the two sides of the sensor. The amount of residual oxygen in the exhaust fluctuates sharply in response to the variation in the iinduction mixture’s air/fuel ratio. Oxygen sensitive voltage generation ranges from 800 to 1000 millivolts for rich mixtures to as low as 100 millivolts for lean mixtures. The transition from rich to lean corresponds to 450 to 500 millivolts. Heated oxygen sensor An electric heater element (see Figure 4) is used to warm the ceramic material when the engine is operating at low load factors. At the higher load factors the sensor’s temperature is determined by the exhaust gas. The heated oxygen sensor helps ensure low and stable emissions due to the consistent maintenance of optimal operating temperatures."

For more details check the link, the info was supplied by the Bosch engineers that designed the O<sub2</sub> in our cars. The wires are just wires and can be cut, spliced, crimped, soldered etc w/ no liability.

Thank you, Professor Verburg!
(My unplugged O2 sensor also thanks you).

Thanks Bill. Took the words right out of my mouth. :-)

Sherwood Lee

Guys:
Since this same topic was discussed on Rennlist, and since the same Bosch rep was involved, see his ( emotional) response to my further questioning. Still...there is SOME info that is still useful ( construction differences between Bosch and others, etc).
Here it is...

Listers:
I forwarded the opposing ( but seemingly valid) view held by many on this List that O2 sensors don't behave as I said they did...based on my Bosch tech's description ( re: air passage under wire insulation).
Here is his ( admittedly emotional) response.
I guess decide for yourself,..I offer this only to complete this sorry chapter. Since ( in this case)I didn't ask permission to repost his reply, I will maintain his anonymity, in fairness to him. I had , however, gained his permission to paraphrase his first response to me.

--Wil Ferch

( address snipped)..Bosch rep response follows:

Look at my email address...you are getting the information from the horse's
mouth, that should be reason enough.
Believe what you want, but it is the truth and we make over 3 million per
year(Do you?). I refuse to argue as I know what is correct. The truth is
that these sensors pull a vacuum on the wire harness drawing in air through
the harness(yes air can actually pass between the insulation and the wire)
and replenishing the chamber(hence the importance of the sealed connector as
water could possibly be drawn in). I do not know what you mean as
"communication" but read my earlier posts as to how the sensors function.
The sensor generates voltage in a rich gas environment...bottom line. The
reference air is necessary for the ion activity in the Zirconia and is
replenished through the harness....bottom line. In fact we test our sensors
by pressurizing the wire harness and making sure that no air escapes from
the sensor body..hence it is totally sealed. We also submerge the sensor in
a water bath while it is operating, just to make sure that no water is drawn
into the body and rendering the sensor useless. Your Ford friend is
referring to our competitor's sensor NTK, which has a breathable membrane on
the sensor body to counteract contamination problems that Bosch sensors
don't experience.
Your friend is incorrect(in the case of the BOSCH sensor), this is
interesting because a lot of our business is with Ford. The rest of his
comments are similar to ones I have stated previously.
Why are you arguing these points, I am trying to help you but you are making
it difficult and are pushing me away from the Rennlist. It makes me angry
when people assume certain things(with nothing to back it up) and want to
argue their point. I have data, do you? When you have data that shows that
the BOSCH sensor does not pull a vacuum on the harness and breathes through
the sensor body come talk to me, otherwise assumptions mean nothing.
Replace your sensor with a three wire Bosch sensor as it is the best sensor
in aftermarket, drive your car, and please leave it at that. I shall post
no more answers to O2 questions(universal replacements or any
other)....thanks to the response of arguments that I have had to write
rebuttals for.
I have no problems with the statements from the Ford guy, except that he is
referring to a NTK sensor and not a Bosch.
In reading the email below you are still missing it as far as how an O2
sensor functions. See my earlier replies as to how it actually functions(or
search the web). Engine compartment air is not bad, but water and other
contamination could be introduced if the connections are not sealed, harming
the sensor.
I was a credible source for O2 information but my comments will no longer be
available.

-----Original Message-----
From: Wil_Ferch at praxair.com [mailto:Wil_Ferch at praxair.com]
Sent: Wednesday, August 28, 2002 8:57 AM
To: XXXXXXXXXXXXXXXXX
Subject:


XXXXXX:
I appreciate the information given me earlier on the various O2
sensors...however...
I've taken a lot of grief about the assertion that O2/air having a
"communication" path back to the computer inside the cabin of the car ( you
and I had a similar discussion at the very beginning. My question at that
time centered around ..."How can air travel under the wire insulation AND
through the various plug connectors along the way"..I still have trouble
with truly believing that...yet I went ahead with your description anyway).

The core question is whether there is indeed a small hole or gap at
the sensor body itself to admit air. If so, I then have other concerns
about weather-tightness , and such, since the sensor is located directly
behind the rear wheel in a 911. If so, is the sensor protected by a
silicone-rubber or Teflon boot, etc .. ?

See the attachment below as a representative sample of how this was
received by the technically-astute members of our web group. I think you
will find it interesting, and hope to hear from you ( pro or con)...about
this.

Thanks!
-- Wil Ferch

(snippeed attachments of various Rennlist responses..)


:eek:

Oh, oh, we've made a Bosch guy *mad* at us for our temerity for questioning his..... authority.

I guess we can't ask him then, how all this transfer of air takes place when one splices (solders) the single wire O2 sensor as per Bosch instructions?

After reading the tech rep's response, a phrase came to mind: "Get a grip..."

Me thinks he takes this just a wee bit too seriously.

This bosch rep is full of crap, I'll bet 1K on it just to make it interesting. There is no flowpath for air to get from the computer to the sensor. Does the air somehow pass through the electrical connector that is located in the engine compartment of my SC? Not a chance! This guy(a sales rep) probably spends most of his time peddling spark plugs and such to auto parts chains and doesn't have a clue about the actual design of their products. I've met more than a few salesmen at car dealerships who didn't know a darn thing about the car they were trying to sell me- not engine size, horsepower, not even what the standard equipment was. If someone who's trying to sell you a 20k plus car is so uninformed, what makes you think a sales rep peddling $5 spark plugs and $40 O2 sensors knows anything?

After all the discussion. What is the best replacement 02 sensor to get for an `87 Carrera? Obvoiusly based on price alone not the Porsche branded one. I have no problem splicing and shrink tubing the proper connector to the universal one. I'd just like to get the proper one for the best price I can. Where would I get one that fits that description?

Thanks,
jw


SmileWavy

I think the Bosch "rep" is getting some false info too. When questioned about it, he should have verified it instead of relying on his 02 sensor belief system.

JW,
If you don't mind splicing and cross-referencing wire colors:

3-wire sensor from JC Whitney @$52.95
4-wire sensor from Summit Racing @$50.00

Sherwood Lee
http://members.rennlist.org/911cars

Now that we got that out of the way...

NTK makes a four wire sensor for Chrysler that I use in my 86 Carrera. $61 at the auto parts store but you need to splice a male end to your harness.

Tweeks sells an 02 sensor for an 86 3.2 for $239.99. I wonder what it is at the dealer?

A little closer inspection on the 02 sensor says assembled in USA, NTK, 5233038.

It seems that NTK Technologies and NGK spark plugs are the same company.

So, if you like NGK spark plugs you might just like NTK 02 sensors too.


Cheers,

Joe

http://forums.pelicanparts.com/uploads/B2.JPG

It would appear that particular tech rep has been wearing his underwear a bit too tight!

It doesn't take an advanced degree to tell that he has been blowing way too much smoke and offering little, if any, substance in his rebutals. Current sealed, and waterproof O2 sensors are a relatively new development ... and the rep has totally misrepresented the reason for the sealing! Any ordinary electrical connector interposed between sensor and DME would prevent the 'so-called' replenishment in his 'junk science' theory! Besides, there has been no evidence given that replenishment is required! I have seen no information about O2 sensors that indicates any oxygen is 'consumed' on the reference side of the sensor ... so, why would there be any need to replenish?

I have seen plenty of sales and tech reps over the years that have gotten aggresive and hostile when their technical 'info' has been questioned as presented, and this guy is no different!

I just purchased a unviersal sensor from another vendor (Pelican didn't sell the universal one), and I soldered the wires, then covered them individually with heat shrink tubing, and then covered all of them with a larger piece of heat shrink. The spliced universal sensor was intalled yesterday, and the car seems to be running fine. I suspect that I could have simply taped the wires (thought not a good idea given the proximity to the exhaust system), and the car would still be runnining fine. I highly doubt that air is somehow running up the newly-spliced wires. It just doesn't make sense. The tech rep has got to be wrong.

(FYI, NGK/NTK makes a three-wire sensor that will work in the car. I decided to keep my car Bosch, however.)

While I appreciate Wil's attempt to get some solid info on the O2 sensor debate, I'm not sure I totally accept the Bosch rep's explanation.

I don't know where the reference air for the Bosch sensor comes from (nor do I care, to be truthful) but, I do know a spliced in Ford (Bosch) sensor works. A couple years ago I was checking\adjusting everthing on my 951, air-flow, air temp., throttle switch, etc. (hey, it was Saturday and better than mowing the lawn) and when I probed the O2 sensor with a meter I got nothing; obviously, I wanted to replace the non-functioning O2 sensor. I shopped/asked around and was advised (reputable source, even gave me the part number) the Ford sensor was the same except for the connector. I bought one (about $30), spliced on the Porsche connector (3 wires, individually soldered and shrink tubed) and installed it; I brought the car up to normal operating temp. and probed the sensor connection at the DME - it dithered beautifully, just like the book said it should. Now, the 951 sensor makes a connection at the firewall (behind the engine) so it's reasonable well protected from road "crud", but I know there is no continous "insulated wire" to the DME. So, I don't know where the ref. air comes from, but I do know the non-Porsche sensor works.

Have fun you guys,

Jerry M
'78 SC (O2 sensor? we don't need no stinkin' O2 sensor)

Closed Reference -- What a concept
 

Exactly! This is what I was hinting at back on page 1 of this thread.
quote:--------
What if the reference side does not need to breath?
What if the reference side does not "use-up" any O2? . . .and yet some tech guy assumes it must ? ? ?
------
Exec. Summary: oxygen is not consumed. . .

SO this is the way it sits in my head, but I've tried to make it presentable here;

This O2 sensor is measuring a force, emf (eletromotive force) to be precise. Keep in mind, measuring a force, and using a force, are two different things. For example, if you step on a bathroom scale, it does not consume you as it gives you a force measurement. . . .lets hope not, those whom get consumed with their weight. . . oh-oh, right . . .eh-em
Back to this O2 sensor, if your measuring device has high impedance (no current leakage) it will not consume what it is measuring.
The captive O2 will stay as a reference, just as your bathroom floor provide an opposite reference force.

Say there *is* a bit of "leakage" (voltage; not something on your bathroom floor):
If sensor equipment does consume what it is measuring, electrons are what it is consuming. The Oxygen is still there; just a bit naked, in the form of an ion.
Furthermore, the O2 sensor then has become an Oxygen-ion generator. (meaning it will push/pull electrons on/off O2 molecules.)
In a closed O2 reference this is still workable. The sensor is grounded allowing the captive oxygen ions to steal electron to replenish themselves as needed.
It work for me . . .but then so does unplugging the damn thing.

Guys:
Allow me some more comments on this, since I had the most dialogue with the Bosch rep:
1.) He adamantly says he's a Development Engineer and fairly bristled when I suggested that he may be a Sales Rep..and after I said that my experience along these lines sometimes has me encounter sales-types that give well intentioned, but false answers.
2.) To give him some slack, there is evidence that suggests that NTK's are not sealed..and that Bosch are sealed. Over-generalized, perhaps, but I'm sticking with Bosch.
3.) O2, IMHO, can be consumed if if the encapsulated air ( O2) exists at some times at room temp, and at other times close to 600 degF. Either the contained gas will experience high pressure swings, or it's allowed to "breathe" in some fashion.
4.) I've experienced the phenomena where air breathes under the wire insulation...this is not too far fetched. His story breaks down when he says the air path continues to the computer ( through the connectors....THAT doesn't make sense). Compromise...maybe the air can flow to the first connector, where there is no moisture and road grime, and therefore is OK.
5.) Here are the Bosch equivalants for mid 80'd Carrera's, again from the Bosch rep, who says these have proper ceramic characterisitics, and proper heater wattages:
15725 ( 0258005725)...universal type
15726 ( 0258005726)...universal type

Notice the relationship between long and short part numbers..


13913, 3 wire Ford...I think it has 8" leads
13953, 3 wire Ford...I think this has 16" leads
He suggests sticking with the universal connectors for the universal kits, and also suggests soldering and heat shrink the Porsche connectors when using the Ford parts.

--- Wil Ferch
pioneering straight info has its risks!
:rolleyes:

You got that right!

Can we now get back to our regularly scheduled information regurgitation? ;)

I've experienced the phenomena where air breathes under the wire insulation

Yeah?
A phenomena you say?
And what *kind* of wire, cable, insulation etc. exhibits this "breathing" phenomena?
:confused:

Lets remember some basic laws of physics. Nature abhors a vacuum and is always moving towards equiliberum, so as any of the air (20.9% oxygen) is consumed(mininmal) the trapped and resident air in the connecting cable is adequate to replenish it. (think about it as the motion in a freshly poured Guiness). This zirconium oxide cell is the very same technology that we sell for flue gas emissions on industrial burners only much smaller. The resident air and "tramp" air in the cable provide enough O2 to run a sensor for 100's of years.