fast951

I'm pasting a copy of the installation instructions for a Bosch O2 sensor. This came out of a Bosch document




Hope it helps...

MySwiss

Well,I can confirm this as well John.It can't be soldered,because it's a stainless steel wire that is used,and regulor wire and solder will not work.

Perry 951

I've soldered my last 2 without issue. If you use 60/40 nickel solder, the stainless will grab it fine. Glue and heat shrink to prevent corrosion.

Wonder why they say it is a no no? Of course, you don't want to splice in 1" from the sensor, but if you do it at the end of the 12" lead, it shoud be ok.

washington951

i did what perry did and now i'm confused. i spliced at the VERY END of the lead coming FROM the sensor. soldered in the OEM connector, plugged it in and went. works great as far as i can tell. AFM wasn't sweeping before the repair - which is why i started looking for something amiss - indicates just fine now.

fast951

What is there to be confused about. Follow the manufacturer instructions...

awilson40

exactly...I didnt know this and soldered mine, as an ET I solder everything Then my car would run fine for about 15 min then like crap...checked the O2 voltage and it was reading 0v so the DME was forcing rich. Let it sit, and it would be fine, O2 sensor responding fine...then after 15 min or so...the sensor voltage would drop to ov. Replaced the sensor using approved connectors and havent had a problem sense.

Perry 951

Not that I disagree with that, but I still question it. Wire is wire, and as long as there is a good connection, be it a splice and solder, or a mechanial punch, the results should be the same. I'll take a section of stainless wire, both the same length, and use a snap connect on one, and solder on the other. I'll do an Ohm check and voltage loss at 14v and see what happens.

It could not be because of a heat related issue. I am quite certain the wires at the sensor get a lot hotter during a track session than they would if I soldered a small joint 12" away.

If we always followed the manufacturer's distructions and did not ask questions, we would all have stock 944's.

awilson40

Its not that you cant solder the wires...you can...I did.
Its that for an O2 sensor to operate, It has to have a supply of outside air(reference air) to compare to the exhaust stream. On older style sensors, this air was supplied via holes in the sensor housing. It was found that these holes would get plugged overtime so the engineers designed a sealed sensor that draws its reference air thru the wire strands inside the insulation. If you solder the connections, then the solder seals the path for the reference air and the sensor cant 'breathe'

keith

that's the best explanation of the "don't solder" reason I've heard to this point, awilson40. And I've heard the reason several times on this board (about the air signal).

fast951

Look at the last 2 bullets/paragraphs in the document I posted. It's well described...

washington951

well, fast951 - there IS something to be confused about. mine IS soldered AND appears to work just fine. according to the gospel, this should not be a) possible or b) operational. mine has proven to be both - hence my confusion.

like i said - i'm going to leave well-enough alone and wait for something to fail before i 'fix' it...its interesting tho and your post with the directions from the manufacturer is self-explanatory - however, there are MANY things that i've installed (not just in cars) that you DON'T install per the manufacturers instructions, so i don't think that finding an alternate way to do things is unheard of or unacceptable - unless it results in something not working...which this isn't the case. would i do it differently?? sure - and i will 'fix' the problem next time i need to change the sensor.

SimonK

I thought I ll chip in here being electronics engineer...

''Not that I disagree with that, but I still question it. Wire is wire, and as long as there is a good connection, be it a splice and solder, or a mechanial punch, the results should be the same. I'll take a section of stainless wire, both the same length, and use a snap connect on one, and solder on the other. I'll do an Ohm check and voltage loss at 14v and see what happens.''

Wire is not a wire! They have different resistance depending on the thickens and material. I would of thought at a delicate application such as o2 sensor - resistance is important. Depending on the blob of solder, you would also get ever so slightly different resistance values. Usually not a problem but in this case....dunno could be...

adrial

So this means we have to buy the $200 factory bosch sensor??

fast951

No, no need to get the $200 O2 sensor. Use crimp on connectors, heat shrink tubing over them and you are done...

87uk944t

what the hells an o2 sensor and whats its purpose??
sorry for being so ignorant!!