Does anyone know what coating is on the new automotive wire these days?

I was trying to put a new O2 sensor in my sidepipes which requires lengthing the two wires...and even after using sandpaper on the wire, I could not get it to take solder.

Now I have been soldering since I was a kid, so I know how to solder, but have not been able to do this harness. Whatever the coating is, it is electrically conductive, but just will not take solder. Only alternative is to crimp.

Thanks,
LannyL81

 

Flux doesn't help??
Betcha its either alumel or chromel wiring nothing will solder to that

 

I'm not sure if you're supposed to solder or change the length of sensor wires.

Take a look here for one argument

http://forums.corvetteforum.com/c6-t...post1567411670

 

That's how the sensors work- alumel/chromel junction. You might/maybe get silver solder to stick, but it'll jack up the resistance and your readings.

 

I do know that they make harness extensions for GM O2 sensors. My son had a set out in the garage he used when we put headers on his 00 Camaro. He later changed to a set of rear Corvette O2 sensors because they came with long pigtails and eliminated the need for the extensions. He may still have extensions, if you are interested PM me and I will ask him about them.

 

I hear what your saying. I went through that also. I tried cleaning the wire with solvent before I soldered it. It almost looked like an oily coating. Even then I had to use a lot of heat to get the solder to adhere to the wire.

 

I read about the sesor oxygen reference from the air along the wire insulation as well, but I thought this was where the wires go into the sensor...not all the way to the connector. The wires at the connector are inside the connector body...???...more confusion.

The wire might be stainless steel or nickle plated copper or something like that....neither will take solder, so I am just going to try the butt crimp connections and see what happens.

I am getting the O2 sensor error code all the time and the sensor end was full of carbon when I took it out yesterday....I knew I was running way rich....have got to get this working

 

If you add-on wire that is made of different material than the original wiring, you will alter the small voltages that the sensor generates--which will alter the results. If there are extension wiring segments for the sensor you have, purchase what you need so you don't mess up your system. You might save a few bucks on the wire, but you'll pay a lot more than that on poor fuel economy or burnt valves if your sensor doesn't regulate fuel use correctly.

 

Chromel/Alumel wires are used in a K type Themocouple which is a temperature sensor, not an Oxygen sensor.

Thermocouples create a voltage due to a temperature difference between the ends of the wires.
You can't determine the temperature at the sensing end of the wire if you don't know the temperature at the measuring end. Adding copper wire extensions to a thermocouple could lead to erroneous readings.

Oxygen sensors are not thermocouples and work through a different mechanism.
The sensor voltage is generated by the sensor (Not by the wires).
You should be able to use copper wires as an extension with minimal impact.
If you can get them connected.

 

But.... there is still a very good chance that the wires coming out of the sensor are not copper and will not solder. I'd suggest asking the dealer/supplier, but probably you'll have to use a crimp connection.

 

If you are having trouble soldering the wires, and they do not appear to be copper, that's good enough reason to ask if there is a "special" extender wire for the sensor. Just because it "ought to be O.K." doesn't mean that it will work properly. Check it out before you continue.

[Kilroy: As you mentioned, dissimilar metals set up a voltage at their junction...just like with a thermocouple. That will happen whether the sensor is a thermocouple or 'something else'. Are you certain that won't impact the output of the O2 sensor?]

 

Try using plumbing solder, this is lead free solder, basically tin silver. Use an agressive flux, and a large soldering gun. This solder will stick to stainless steel, nickle, gold, tin, and copper. Only thing it won't stick to is aluminum, and I ampretty sure your not dealing with that.

 

The voltage in a thermocouple is not generated at the junction, but is generated in the wires as a result of the temperature difference between the ends of the wire.

Since a thermocouple uses two different types of wire, there is a different voltage drop on each wire. The difference can be measured at one end if you twist the other end together and form a junction.

Based on what I read on oxygen sensors, the voltage is generated by the sensor and not in the wires. You should be able to crimp on a foot of a copper without affecting the output.

I can't say I'm certain until I've personally tried it (which I haven't).
Can't find any info on the net that says you need to use special wire.

 

Thermocouples are used to measure temperature. The wires are made of dissimilar metals and when connected together at one end a thermoelectric voltage is generated at that junction. This voltage is a very low level voltage typically in the tens of millivolts. The voltage generated varies based on the temperature of the junction. The junction where the temperature measurement is made is called the "hot junction".

When the thermocouple wires are connected to a measuring circuit, typically interfacing with copper, another dissimilar junction is formed creating another thermoelectric voltage. The voltage generated at the interface to the measuring circuit junction is called the "cold junction". In order for an accurate measurement of the hot junction to be made, the cold junction has to be compensated for. This is called "cold junction compensation". It is typically done by measuring the temperature of the cold junction, converting that temperature to an equivalent voltage (based on the ice point, thermocouple voltage measured at 32 deg F) and subtracting this voltage from the measured voltage.

Long story short, when dealing with thermocouple wires, using the proper extension wires are necessary to maintain an accurate measurement.

As for the O2 sensor, I don't know what type of wire is used, but the previous recommendation of using an extension cable is right on the mark.

My .02 FWIW.............

Tom

 

I was able to finally catch up with Michael tonight. He told me that his extensions were to go to the guy that bought his old headers. But they were 4 wire extensions.

 

Due to the wording in many textbooks, (not all texts)
It has become accepted that the voltage is generated at the junction.
This is not correct. Its generated in the wires.

 

Tom's right. He obviously has done some work in Metrology....so have I. Four-wire systems are employed to negate unwanted spurious voltage signals. Best to use what is suggested by the component manufacturer.

 

Well that makes three of us then.

Using the wires from another sensor is going to be the safest bet.

However, I still can't find anything, anywhere that says an oxygen sensor uses special wire.

What exactly is suggested by the manufacturer?

 

I purchased a universal four wire O2 sensor for m '81. This has no connector on the end. It did come with four crimp butt connectors and shrink sleeving, with instructions to cut the connector off the original O2 sensor along with as much wire as needed, crimp to the new one and install into exhaust.

There was no mention of maintaining any kind of gap for reference air.

This would be using the same type of wire..more or less. I just used about 10" of copper wire of the same gauge. True each joint increased resistance which will affect the O2 sensor output, by just how much...depends upon the drive current from the O2 sensor...which I doubt is very much...all low level. I think that each connection adds no more than 0.1 ohms at the most...not something my Fluke DMM is going to measure. Worst case is that I may run a bit lean due to the small voltage drop across these connections which again depends upon the current output from the O2 sensor.

Right now though...getting this engine to run leaner would be nice, very nice.

 

Nope. Four wire oxygen sensors are a later design that uses a 2 wire sensor with a two wire heater element. Two wire sensors take 20 seconds to come up to temp and read above .45 volts. Four wire heated sensors take 5 seconds, therefore closed loop can engage sooner.