Proof that 99% of the MKIII's weak link is the owner... (pics)
- Thread starter Doward
- Start date
i would not solder the o2 sensor.
this is going to sound crazy, but air actually travels through the wire. between the actual wire and the sheilding. air enters the connector and travels down the wire to the sensor. this all happens in super small qualties.
i know this sounds crazy and i just learned of this from my teacher who is an ASE master tech.
when you solder an o2 wire you cut off the air to the sensor, and i guess the sensor needs a small bit of air to work correctly.
i hope i explained this correctly
this is going to sound crazy, but air actually travels through the wire. between the actual wire and the sheilding. air enters the connector and travels down the wire to the sensor. this all happens in super small qualties.
i know this sounds crazy and i just learned of this from my teacher who is an ASE master tech.
when you solder an o2 wire you cut off the air to the sensor, and i guess the sensor needs a small bit of air to work correctly.
i hope i explained this correctly
... You're telling me that you need air to conduct the electrical signal?
I understand what you are saying... but that makes, well, almost zero sense.
Optimally, you'd want NO wire, as any wire induces added resistance, and alters the signal being sent to the ECU. But alas, the ECU doesn't want to be mounted on the exhaust (for obvious reasons), and the ECU can't possibly be directly connected to each and every sensor - so we run wires from the sensor, to the ECU. You want as little resistance as possible in the wires, so the signal gets there with minimum distortion.
Which means you want it completely shielded, and for longetivity issues, you also want the wires AWAY from moisture (found in air) as it will cause the wires to corrode over time. Corrosion increases resistance, and you are back at altering the signal.
For an example of this, find someone with corroded battery terminals.
I'm not saying your ASE master tech is wrong, Malloynx, but I'm majoring in ECE, and what you are saying goes against everything I can think of...
Think about it.. the actual O2 sensor itself is actually contained in the end of the O2 sensor housing, which is sealed with the wires coming out of the end of it... If it were not sealed, you'd have an exhaust leak there!
I understand what you are saying... but that makes, well, almost zero sense.
Optimally, you'd want NO wire, as any wire induces added resistance, and alters the signal being sent to the ECU. But alas, the ECU doesn't want to be mounted on the exhaust (for obvious reasons), and the ECU can't possibly be directly connected to each and every sensor - so we run wires from the sensor, to the ECU. You want as little resistance as possible in the wires, so the signal gets there with minimum distortion.
Which means you want it completely shielded, and for longetivity issues, you also want the wires AWAY from moisture (found in air) as it will cause the wires to corrode over time. Corrosion increases resistance, and you are back at altering the signal.
For an example of this, find someone with corroded battery terminals.
I'm not saying your ASE master tech is wrong, Malloynx, but I'm majoring in ECE, and what you are saying goes against everything I can think of...
Think about it.. the actual O2 sensor itself is actually contained in the end of the O2 sensor housing, which is sealed with the wires coming out of the end of it... If it were not sealed, you'd have an exhaust leak there!
i'm not explaining it good.
here this is taken from a website,, backing up my instructor
I was raised to always solder and heat shrink my connections, but current thinking gives the green light to using butt connectors on these jobs, as long as heat shrink is used over the butt-splice. Don’t do what one do-it-yourselfer did in Figure 10; he twisted the wires together and wrapped it with electrical tape! Please remember: Some oxygen sensors use the wiring (actually sheet on wiring) as a channel for reference oxygen. If you cut off the connector, solder and shrink-wrap, you may be blocking reference oxygen.
here this is taken from a website,, backing up my instructor
I was raised to always solder and heat shrink my connections, but current thinking gives the green light to using butt connectors on these jobs, as long as heat shrink is used over the butt-splice. Don’t do what one do-it-yourselfer did in Figure 10; he twisted the wires together and wrapped it with electrical tape! Please remember: Some oxygen sensors use the wiring (actually sheet on wiring) as a channel for reference oxygen. If you cut off the connector, solder and shrink-wrap, you may be blocking reference oxygen.
From cutaway diagrams of O2 sensors I've studied, the oxy-reference channel is always a hole in the sensor body, usually very close to where the wires come out of the sensor. The only way I can think for splicing to be an issue is if you accidentally cover the "breather" hole on the sensor body.
As for not soldering, the best reason I can think of is that the wires are often stainless steel or coated with another hard metal. Either way, they're very difficult to solder. In addition, the reason for the tough wires has a lot to do with the heat that the O2 sensor is subjected to. Other materials for wire simply oxidize or wear too quickly under the stress and become poor conductors. It's also possible that normal solder won't stick to the wires or will melt under the heat.
Obviously, none of this is applicable if the splice is more than a few inches from the O2 sensor! If that's the case, the hardest thing will be getting the solder to "stick" to the conductors. So there you go, crimp splicing is easier but not necessarily the only wise way to go! IMHO of course!
As for not soldering, the best reason I can think of is that the wires are often stainless steel or coated with another hard metal. Either way, they're very difficult to solder. In addition, the reason for the tough wires has a lot to do with the heat that the O2 sensor is subjected to. Other materials for wire simply oxidize or wear too quickly under the stress and become poor conductors. It's also possible that normal solder won't stick to the wires or will melt under the heat.
Obviously, none of this is applicable if the splice is more than a few inches from the O2 sensor! If that's the case, the hardest thing will be getting the solder to "stick" to the conductors. So there you go, crimp splicing is easier but not necessarily the only wise way to go! IMHO of course!
I can see micky's point there - if the reference hole is blocked, you'll have a problem - but that's just it, usually the wires aren't the reference point... Either way, this is the wiring on the end of the harness - not the sensor, so I think it's a moot point... 
Anyway, here's tonight's accomplishment. I like the black on grey look!
I fucking like it!
Hardcore industrial look. No play here, all business
Of course, pulling the masking tape back off, after letting the grey sit for 2 days, still pulled some of the grey back off... guess I should have baked it, first, eh? Oh well, I'll touch it up (it's mainly on the 3000 pipe)
Anyway, here's tonight's accomplishment. I like the black on grey look!
I fucking like it!
Hardcore industrial look. No play here, all business
Of course, pulling the masking tape back off, after letting the grey sit for 2 days, still pulled some of the grey back off... guess I should have baked it, first, eh? Oh well, I'll touch it up (it's mainly on the 3000 pipe)
Looking good Doward! Did you seriously put masking tape between the stripes? That would have been a nightmare!
a stiff roller would have worked on the stripes too,
I love the color scheme it is exactly what i have always wanted to see, good work, i like your attention to detail.
I love the color scheme it is exactly what i have always wanted to see, good work, i like your attention to detail.
Actually, I have an old circuit tester that teh battery like.. melted it... Cut the wire that runs to the alligator clip, and low and behold - fit like a glove down in between teh stripes. Good and tight, so it didn't move around at all. After I touch up the other valve cover and the 3000 pipe, I'll post pics... I'm really digging the grey/black on the 3000 pipe, in particular
After I touch up the other valve cover and the 3000 pipe, I'll post pics... I'm really digging the grey/black on the 3000 pipe, in particular
looks awesome man! can't wait to see the 3000 pipe... just dont do the entire engine bay in all grey... like all the vac hoses and shit in grey... i've seen that done before... looks like somebody chucked a can of paint in their engine bay... but so far yours is looking pretty damn sweet! (I love the rough texture of that paint!)
Hoses are all going to be black, though for now I think they will simply be rubber black, until I can find somewhere to get black silicon for all the vacuum lines
The hardpipes (when I get around to making them, lol) will be the same cast coat iron, with black silicone connectors, more than likely.
The hardpipes (when I get around to making them, lol) will be the same cast coat iron, with black silicone connectors, more than likely.
good, just as long as you have some accent colour haha.... I think that textured silver/grey will look awesome in contrast to glossy black!
Here's a quick one of the 3000 pipe...
Like I said, I need to touch it up a bit tonight after school
Like I said, I need to touch it up a bit tonight after school
Tractor paint scheme... lol
Looking good, but I feel that it should be broken up a bit more. Perhaps paint the rear timing cover black instead of gray, but it's too late. No complaints here. Looks good nonetheless.
As far as o2 sensor wiring goes, or any wiring, a butt connector stripped of it's sheathing and heatshrink covering it is more than adequate. Better than solder I've found as the heat from solder can actually weaken the wire.
The soldered part will hold great, but 1/4" away, the wire will break.
Looking good, but I feel that it should be broken up a bit more. Perhaps paint the rear timing cover black instead of gray, but it's too late. No complaints here. Looks good nonetheless.
As far as o2 sensor wiring goes, or any wiring, a butt connector stripped of it's sheathing and heatshrink covering it is more than adequate. Better than solder I've found as the heat from solder can actually weaken the wire.
The soldered part will hold great, but 1/4" away, the wire will break.
Doward said:Hoses are all going to be black, though for now I think they will simply be rubber black, until I can find somewhere to get black silicon for all the vacuum lines
y.
hose techiniques has a great vacuum line kit for our cars, high quality stuff and looks allot better than the stock lines.
I'm liking it... wish the elbow hadn't been so stuck, I would have liked to have shot it, too
Also should have probably spent more time cleaning the compressor housing of the turbo... maybe I'll go back in there, and do something about it *ninja edit*
Yeah, wtf was I thinking... I'm pulling the turbo back out tomorrow, and cleaning it up better than that... wtf!!
