Is Bosch Universal Oxygen Sensor Installation Video Correct?
It is very hard to believe the electrical wires can let air go through:
http://youtu.be/3Yt6Lg0oU58

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This has been discussed many times before here at Pelican HQ. I've written five books on Porsches and BMWs, and the fact of the matter is that I still don't know for sure. The goofy posi-lock system that BOSCH has for these connectors seems a bit odd to me. In general, the O2 sensors are supposed to be water-proof, meaning that they have to work submerged in water. So, the air-reference signal that the sensor needs to measure O2 has to be gathered through the connector itself. I'm not sure if soldering by itself is the issue with not having a proper connection, or whether it has to do with the fact that people seal the connection with tape and/or heat-shrink tubing. I would agree that soldering by itself would probably not cause a problem. The act of covering up the soldered connection is what causes issues, I believe. This is just my opinion - I'm not 100% sure. In all of the books that I've written, I recommend that our customers stay away from these generic sensors and instead use the proper OEM BOSCH ones with the proper car-model-specific connector installed and attached at the BOSCH factory.

- Wayne

The O2 sensor uses a supply of reference air and Bosch is adamant that this small amount of reference air is replenished via the wiring. If the body of the sensor is sealed it has to pull air from somewhere. I figure they might know what they are talking about even it I don't fully understand it.

Crimp, don't solder and use heat shrink tubing or use the supplied Bosch connector.

Can't go wrong with the factory sensor but plenty of people, myself included, have used Bosch part number 13913 (1986 Ford Taurus). Cut the ford factory connector off the sensor and splice it into the factory Porsche harness. If you stagger your splices you won't end up with a lump in the line and you can reuse the factory heat sleeve. I've got around 10k trouble free miles on this set up. -J

The connectors are pretty cool from my statistical sample of one installation on a Ford Focus. A four wire O2 sensor is a pain to strap together - it sucks time - and from that viewpoint they are goofy as can be. But there is beauty in the design.

Note that the OP is referencing a Bosch video that clearly states the AIR must pass through the ELECTRICAL WIRES to make the O2 sensor work properly. Pffffft. That is hogwash.

Even though JAR2003 refers to reference air, this is impossible.

Prove me wrong.......

http://forums.pelicanparts.com/uploa...1386115337.jpg

While it is ridiculous to think that the reference air passes through the wire, Wayne is correct that it passes within the the wireing sheath along w/ the insulated wires and then through the connector, This is clearly stated in both training manuals and shop manuals

Anyone know how to find sensors based on connector type and wire length? The OEM Bosch sensor wires were not long enough when I installed headers on my '84 3.2, and it would be nice to avoid a splice (BTDT).

Fair enough. This is a technical issue that I do not fully understand but I am interested in understanding, so I will research and attempt to post an explanation in layman's terms.

The turtle is pretty scary, right?

Two minutes of research.............

For the sensor to work correctly, it must draw clean air down to the sensor through the air gaps in the stranded wire. If you solder the wires, the solder will fill the air gaps in the wire and the sensor will not work correctly.

I am just going to hang myself.

Oxygen Sensor General Information, Testing, and Replacement

Crimped joints are best. However properly soldered wires are fine. The problem is most people do not heat the wire enough and create cold solder joints.

OK, what's the deal with these universal Bosch O2 sensors, then? Should we just cut off the factory connectors and use the universal ones supplied in the kit?

Are they really suggesting that if we were to solder the sensor wires onto the factory connector, we would choke the sensor of reference air?

This really belongs on snopes.com.

The people who invented the oxygen sensor in the first place - the same people who manufacture the specific part you're talking about - put this in their technical installation documentation - in bold type.

That documentation is downloadable from their web site on the internet, linked/referenced in at least 3 threads on the 911 forum. And quoted above by Bob. I first read found this information myself in 2003 on F.R. Wilkes' (a Pelican, BTW) site in 2003.

Sure, there's lots of people all over the interwebs saying "are they really serious" and saying that Bosch don't know what they're talking about.

They must be right, there's so many of them. I guess Bosch must've just made it up. Maybe they needed to sell more connectors or something.

Still hard to conceptualize. However, I been crimpin' since this thread. :)

I think I'll just roll with the universal connectors supplied.

But it would be cool to do some myth-busting and actually measure the O2 signal with different wire/sheath tampering/jiggery-pokery.

I soldered my 81. However, it's what, about a foot away from the sensor itself?

I probably put the shrink wrap tube on it but that is a DIY guy with a blow dryer. Did it really seal to the point of making the solder joint "shunt" the reference air.

There were "open" wire strands upstream and downstream of the joint.

Maybe if I sealed it perfectly, then drove up 7,000 feet above sea level, the "old" reference air would indicate more oxygen than true.

On the other hand, this stuff is witchcraft so I ain't messing with it. Crimping or the fancy half hour to install connectors (4 wire)

From this thread: http://forums.pelicanparts.com/porsche-911-technical-forum/497025-o2-sensor-connector-2.html

And my post #56: http://forums.pelicanparts.com/porsche-911-technical-forum/497025-o2-sensor-connector-2.html#post8259941

F.R. Wilks has been a Pelican a long time; well known in 944 circles for his PowerPROM. His web site has much information about the Bosch Motronic and accessories.

From my post #58 http://forums.pelicanparts.com/porsche-911-technical-forum/497025-o2-sensor-connector-2.html#post8261091

I'd not heard of "lamba wire" before - and never seen any other mention of it. But I'm not that skeptical. And it seems to make sense that the original 80'd sensors were one way - and updated/revised later for better operation.

This would certainly seem to be supported by the statement in the Bosch "Testing 3/4 wire lambda sensors document that says

See for yourself: http://aa-boschap-nz.resource.bosch.com/media/parts/engine_systems__auto_parts/bosch_tipps_lamdasonden_de.pdf


And. again from that #58 post: http://forums.pelicanparts.com/porsche-911-technical-forum/497025-o2-sensor-connector-2.html#post8261091

Let's put that in perspective.

• Bosch invented the Oxygen Sensor
• Bosch make lambda sensors to fit 85% of all vehicles
• Bosch currently make 45 million lamba sensors each year world-wide - and announced in 2008 that they'd made 200 million oxygen sensors at a single plant in North America: Robert Bosch LLC. - Media Center

That statement telling you not to solder the wires is from Bosch's installation documentation for the part under discussion here - the "Universal" sensor.

Seems pretty conclusive to me - but believe whatever makes you happy.

I soldered the wires when I lengthened them to work with my B&B headers. Seemed to work fine.
I have SSIs and a new, unmodified OEM sensor going on after my engine rebuild, so it will be interesting to see if there is a difference.

spuggy - Just discussion. Nothing more. I believe Bosch. As stated before, it's strange to conceptualize.

There is no "force" that pushes/changes out the air. It's odd to a layman.

But you have positive pressure from the exhaust itself...

Sure, completely agree/understand that it seems unlikely when you first hear it, with no background/context. Especially if you had previously thought of the sensor as being essentially as dumb as a spark plug, with a wire/plug on it - like I used to. :)

Except it's not that simple. What seems, just from looking at it, to be an electrical lead with a plug on it is regarded by Bosch engineers as a PTFE formed hose comprising a reference air volume with a permeability within guaranteed limits.... :D

For example, the Bosch reference document for the LSU 4.2 planar http://wbo2.com/lsu/Y258K01005e03mar21eng.pdf gives:

McClaren go into some detail as to how an NGK UEGO sensor works here Lambda Sensors Application Note | Documents | McLaren Applied Technologies. This description seems to me to imply that the reference chamber within the sensor requires constant replacement of the reference air.

This document based on the Bosch planar wideband http://wbo2.com/lsu/oxygen13-17.pdf is a little more detailed - but it's the same tech.

OMG - I read through the first link.

They are serious about this stuff.

Thanks.

Cripes, even talked of bend radius in the PTFE hose.