extending oxygen sensor wiring

[avinesh]

ok guys im doing a single turbo converstion on my 1jzgte soarer just wana know how an where can i get the oxy sensor wires extended coz the wires are too short to make it to the down pipe..thanks in advance guys

[Trls250s]

I dont think you would have to much trouble extending the wires a little bit. The only wires you cant really extend are the knock sensor and another sensor that illudes my mind atm. They are sheilded from the ecu to the plug.

How much of an extension does it need to have done?

[matt dunn]

You are not meant to solder oxy sensor wire, but crimp joins are ok,


and the wire they are made of is a PITA to solder anyway.

[Trls250s]

You are not meant to solder oxy sensor wire, but crimp joins are ok,


and the wire they are made of is a PITA to solder anyway.

heh i did this out of lazyness but for once, it pays off...

[sergei]

You are not meant to solder oxy sensor wire, but crimp joins are ok,


and the wire they are made of is a PITA to solder anyway.

You should be able to extend the wires (via soldering, IMO crimps just aren't good enough, personally I would never use just crimps) before the plug (from loom side). The only good crimps are the factory one, I haven't seen a tool that does the same way as they do it at the factory. Anyway they use solder as much as possible too, like in Y joints inside of loom.

[matt dunn]

Oxy sensors work on such small voltage that the resistance in a solder joint, (and there is) can affect the accuracy.

In reality probably bugger all,

but the correct and approved way is crimps,
if you read the instructions that come with new sensors it says soldering is a no-no, and also some sensors breath through the cable and you can put them out of sensitivity.

[Mr.Phreak]

Not to mention using solder to join wire in a high temp/high vibration area is generally frowned upon.

As Matt said, use crimps.......but don't use cheap crimps or a cheap crimp tool....Pliers are not a crimp tool btw

[sergei]

Oxy sensors work on such small voltage that the resistance in a solder joint, (and there is) can affect the accuracy.


In reality probably bugger all,
but the correct and approved way is crimps,
if you read the instructions that come with new sensors it says soldering is a no-no, and also some sensors breath through the cable and you can put them out of sensitivity.

Ok, please don't take offence in the following (I am talking from theoretical and practical experience, not in automotive electronics but radio/microelectronics):

1) Oxygen sensor voltage is in no way low, somewhere around 1V, narrow band sensor works from hysteresis curve anyway, say 1V rich ~0 volt lean (roughly speaking), Obviously ECU will not care much if there is 1V or 0.98V as long as it is above trigger point.

2) Solder is no way resistive, I would say that crimps are a lot worse, for one when you crimp the layer of oxide remains and acts as small insulator, crimp generally tends to get even more oxydised, and finally crimp is not as strong as solder joint.

3)If the solder was resistive to affect 0.1V range they would not use in say on microelectronics in first place, in fact even amateur radio equipment has voltages in range of microvolts and the resistance of solder joints is not an issue.

4)When you properly solder something it removes the oxide layer from the wire, also since the cross sectional area of the contact increases substantially even if the solder was of resistive material (say like nikel alloys) it would not effected anyway, I can even provide calculations if you wish to continue this debate.

IMO the reason of not soldering the Oxygen wires is because sensor itself heats up substantially that it is enable to transfer the heat through wire to solder joint in amounts enough to bring temperatures close to melting point of such solder making the whole connection unreliable. This is why I said it is ok to solder from the loom side.

But there is solution for heat problem (and mythical resistivity problem) solder containing silver, with melting points close to 400'C it is difficult to solder as some or soldering irons are not hot enough.

Anyway the whole resistance argument is nonsense as there are at least two mechanical connections (plugs, oxidised as matter of fact) between sensor and ECU that add a lot more resistance and noise to the system than any good crimps or soldering joints ever would.

[rollaholic]

i was under the impression that the O2 sensor wire was shielded too, this being the main reason for not adding random lengths of unshielded cable.

[sergei]

i was under the impression that the O2 sensor wire was shielded too, this being the main reason for not adding random lengths of unshielded cable.

It is shielded in the main loom but unshielded at the plug and the sensor.

[pc]

2) Solder is no way resistive, I would say that crimps are a lot worse, for one when you crimp the layer of oxide remains and acts as small insulator, crimp generally tends to get even more oxydised, and finally crimp is not as strong as solder joint.

Agree.
Solder good, crimp bad.

[Dell'Orto]

if you read the instructions that come with new sensors it says soldering is a no-no

I guess the manufacturers of the item don't know what to do huh? Every O2 sensor I've seen says to crimp, not solder. Gotta be a reason for that.

[Mr.Phreak]

The biggest problems with crimping is that people use crimps made out of folded tinfoil, don't use the right crimps for the size wiring they're working with, and thinking that as long as it's flat it'll hold.

People who use pliers to squash crimps should be shot......as should those who use scotch locks.....

[sergei]

if you read the instructions that come with new sensors it says soldering is a no-no

I guess the manufacturers of the item don't know what to do huh? Every O2 sensor I've seen says to crimp, not solder. Gotta be a reason for that.

Reason: Hot.
They say nothing about soldering after the plug do they?

[Lloyd]

IMO the reason of not soldering the Oxygen wires is because sensor itself heats up substantially that it is enable to transfer the heat through wire to solder joint in amounts enough to bring temperatures close to melting point of such solder making the whole connection unreliable. This is why I said it is ok to solder from the loom side.

There is nowhere near enough heat getting to any wiring to cause that. If anything the insulation is going to melt before that anyway

[sergei]

IMO the reason of not soldering the Oxygen wires is because sensor itself heats up substantially that it is enable to transfer the heat through wire to solder joint in amounts enough to bring temperatures close to melting point of such solder making the whole connection unreliable. This is why I said it is ok to solder from the loom side.

There is nowhere near enough heat getting to any wiring to cause that. If anything the insulation is going to melt before that anyway

The insulation on the oxygen sensor is heat resistant, normal solder melts just under 200'C while you can have insulation withstanding over 300'C

[Burning Angel]

the reason why crimps are always used in automotive wiring is that soldered joints break if they are flexed.

well not so much the joint breaks but the wire breaks right after it.

i have had this happen several times on an ignitor plug with too short pigtails.

proper crimps(not the plastic coated crap ones) are more mechanically strong than a solder joint as they hold the insulation as well as the conductor.

for the best conductivity you can solder these as long as you dont let the solder wick up the wire past where the insulation is crimped as this can still lead to the afore mentioned breaking.

if i had the money/patience i would have bought new plugs/connectors for my injectors, cas, tps etc and wired the link wiring straight to them rather than soldering onto the cut loom.

modern plugs etc are also waterproof.

[Calvin]

the reason why crimps are always used in automotive wiring is that soldered joints break if they are flexed.

Also vibrations can crack dry solder joints. I was always under the impression that crimps were better in auto electrician applications

My father, an ex radio and tv repair agent goes one step furthur and recommends crimping and then soldering

ALSO

Can anyone recommend a good quality crimping tool.. ??

[pc]

the reason why crimps are always used in automotive wiring is that soldered joints break if they are flexed.

Also vibrations can crack dry solder joints. I was always under the impression that crimps were better in auto electrician applications
My father, an ex radio and tv repair agent goes one step furthur and recommends crimping and then soldering

If things are soldered in such a manner that it has a dry joint, or that the wire comes under mechanical stress etc etc... that just means it has been done wrong and is nothing to do with solder being the problem.
If soldered wires are loomed up correctly and attached to things to take weight of them, then they will last forever. (this is the same stuff that should be done when crimping)
crimps can corrode.

[nz_climber]

Been working on aircraft for a while now, and there is nothing wrong with crimp connectors! Do them properly with good tools and they will last forever, also if you are worried about corrosion then you can get hermatically sealed splices.

And all looms no matter which connections should be wrapped and secured to remove stress and vibrations from joints