O2 wire harness repair

[Capeasy]

Is this a common problem on our PPVs after only about 8 years? I've been battling intermittent PO174 and PO151 codes for the past 2 years and 2 different shops just wanted to change out the O2 sensors and tell me I probably have an intake leak. So before I give up and take it to a 3rd shop I bout a good $500 Autel scanner and a $100 smoke machine to check for intake leaks (but couldn't find any leaks) . So I finally jacked the car up high enough to get underneath it and discovered this missing insulation at the O2 connector plug. WTH ? How did the last 2 shops miss this.
So either the w I res got brittle from heat or over manipulation of replacing O2 sensors? So any advice on getting that harness out and soldering on a new pigtail plug connector?
Thank you for any help on this topic

[Capeasy]

Trying to fix this correctly would involve pulling the harness out to solder a new connector. Is it possible to intercept these same 4 wires say up near the top of the motor instead and just onit the current wires in that harness and just run new wires down to the O2 connector?
Also I can't seem to locate the O2 heater fuses in the under hood fuse box? Any help would be appreciated.

[JoeR]

Sorry for the late reply on this, but the O2 heater power comes from the underhood fuse box. They are labeled EMIS fuse #1 and #2. They're 15 Amps.
Seal them up carefully and don't solder the wires. O2 sensors rely on comparing outside O2 to O2 inside the exhaust pipe. Solder can ruin that supply of air. There's an interesting document by Bosch floating around on it.
Joe

[s/c'd cav]

Seal them up carefully and don't solder the wires. O2 sensors rely on comparing outside O2 to O2 inside the exhaust pipe. Solder can ruin that supply of air. There's an interesting document by Bosch floating around on it.
Joe

WTF ? you on crack !! there is absouletly NO oxygen being sucked in or out of the inside of the wires to be metered by the o2 sensor !!!

the reason they do not recomend soldering , is it changes the resistance at the solder joint , which can alter the low voltage signal the o2 sensor creats

[JoeR]

LOL. You're so sure of yourself.

No air is getting sucked down the wires, but according to Bosch reference air is provided through the wiring. I'm sure it's a trace amount. Either way, it's not my explanation. It's Bosch's.

Here's the original Bosch video: https://www.youtube.com/watch?v=ex1Hki6-NHw

I'm sure you won't agree with them. What do they know, right? They only invented the O2 sensor.

Joe

[s/c'd cav]

LOL. You're so sure of yourself.

No air is getting sucked down the wires, but according to Bosch reference air is provided through the wiring. I'm sure it's a trace amount. Either way, it's not my explanation. It's Bosch's.

Here's the original Bosch video: https://www.youtube.com/watch?v=ex1Hki6-NHw

I'm sure you won't agree with them. What do they know, right? They only invented the O2 sensor.

Joe

BAHAHHAHAHAHAHAHAA !!!

ask yourself this , where and HOW does the oxygen get into a SEALED wire ? and how does it get through their sealed screw connectors ? also , then why SEAL a wire ? how does the air get past the metal terminals ? also copper doesnt like oxygen it corrodes


i suppose you also believe in turbo encabulators also ?

https://youtu.be/MXW0bx_Ooq4?si=xY09O8H2vvQJtpMp


gotta love people that believe everything on the interwebs !!!

[Pursuit]

OK, My curiosity was piqued...
So, I found this video. Comparing the two videos, there is outside air is available to the O2 sensor from gaps between the wires. I would also agree that you would not want to solder the wires as this would create a resistance and give an inaccurate reference voltage. The Bosch Smart Link System is a great electrical replacement solution. At 1:20 is the beginning of the cut-away of an O2 sensor and at 2:13 it shows that the outside air sample is heated at the top of the of the O2 sensor. It does not appear that there is any circulation. I am curious now as to how far away from the O2 sensor is the outside air drawn? How do they minimize the effects of water and dust? Does the protective shielding act as a pathway? Or is the O2 sensor vented at the top for sampled outside air?
I will admit that I learned a little more today.
 
https://www.bing.com/videos/riverview/r ... ORM=VRDGAR

Regards,

Maurice

[bstoner]

The oxygen sensor takes in outside air on the backside of the oxygen sensor. The bundle of wires has ambient air within the bundle that is open to the backside of the oxygen sensor. I think the video is saying not to solder because of the possibility of smoke/fumes contaminating the sensor or an improper splice restricting outside air from the point of the splice connector to the rear of the oxygen sensor. You just need to solder/repair wires after the oxygen sensor connector. No different then how we add O2 extension harnesses which will cause a minute increase of resistance, but still doesn't change the accuracy of the sensor.

[JoeR]

at 2:13 it shows that the outside air sample is heated at the top of the of the O2 sensor. It does not appear that there is any circulation. I am curious now as to how far away from the O2 sensor is the outside air drawn? How do they minimize the effects of water and dust? Does the protective shielding act as a pathway? Or is the O2 sensor vented at the top for sampled outside air?
I will admit that I learned a little more today.
 
https://www.bing.com/videos/riverview/r ... ORM=VRDGAR

Regards,

Maurice

Multiple manufacturers claim there is a vent hole under the thimble for sampling outside air. Others claim only sampling through the harness. In one Bosch class the trainer claimed they used a vent hole and had the harness as a redundant system. It would make sense to build sensors without a vent hole. While the thimble would protect the vent hole from the elements, it would prevent you from mounting it at angle angle past 90 degrees. As soon as the harness end was lower than the sensor end, the thimble would hold water and prevent air from getting to the vent. I bet this is why they stress that on their universal sensors that you don't solder them. If they're universal, then they have no idea what position they'd be mounted in, and over the years I bet there's been quite a few vehicles that had the O2 sensors pointing up hill.
Most folks don't solder them anyway, because the O2 harnesses are stainless or plated wires. Some solder mixes won't stick to them.

Further documentation on this.
I-Car references the GM procedure of not soldering O2 wires. To quote them and GM: “Caution: Do not solder repairs under any circumstances as this could result in the air reference being obstructed.”
See the whole Document here: https://rts.i-car.com/collision-repair- ... n-947.html

Also, directly from GM service information:

[Capeasy]

Wow ! This keeps getting more interesting lol
I'm still in the middle of trying to pull out the complete wiring harness from the transmission all the way up thru the back of the motor to have better access to making the repair of the exposed wires at the old 4 pin connector. I should have it out by the morning but spent a couple hrs trying to unplug all the knock sensors, etc above the starter which was no fun to remove while leaving my Tri-Y headers in place. I noticed a couple other connectors that either have brittle or broken locking clips and a some exposed wire right behind the connectors possibly from heat and over manipulating and bending the wire during the engine mods and a 10 year old harness. So I think I need to source some new replacement pigtails like the one i got for the O2 connector. I'm not even sure why GM used so many different style connectors on their sensors, maybe so you don't mix them up ?
So if I'm successful in getting that harness up and over the back of the motor under the hood where I can evaluate if I can just cut off the bad connectors and use these new Solder seal Wire Connectors, either the crimp style or heat and shrink type
https://www.amazon.com/dp/B073RMRCC3?re ... tails&th=1

This is the best pigtail I could find online for the O2 Harness
https://www.amazon.com/dp/B07HQYB4QN?ps ... ct_details

If there's enough room I would stagger the connections so the harness dosn't have a big bulge in it? I hope this dosn't interfere with the sensors since I'm repairing the Harness and not messing with the actual O2 pigtail. I seen the video and Articles posted about NOT to solder because of changing the resistance or the AirFlow restriction I just dont know about that one, I'm looking at the wires coming out of the Denso O2 and I see the seal that would keep out any water and probably air as well BTW I like Bosch sensors but statistics show Denso's O2s seem to hold up better.

OK, I'm open to any good advise before I proceed to repairing this Harness