I'm installing long tubes this weekend and will be extending the O2 harnesses myself. My question is what gauge wire do I use to extend them?

 

I wouldn't do that, I would just pick up a set of extenders. The O2 wiring is very specific, in that it has to have a certain amount of resistance to function properly. It's similar to thermocouples.

 

Don't cheap out, buy the proper harnesses.

 

i thought the same thing, until i was strictly told that there is a certain resistance.

do like they said and buy the proper extension.

 

If you do decide to do it yourself, don't alter the wiring on the O2, but extend the wiring of the car's harness, using the same gauge as what is there. Altering the wiring of the O2 can compromise it's performance.

 

the only way you could really do it is find someone with an extension, take a multimeter measure the resistance, and get 2 variable resistors, solder them in line with your extension and adjust them to the same resistance.

but thats alot of work.

 

I'm just curious as to why there would be a difference between altering the 02 sensor harness, opposed to altering the car's harness?

BTW: It seemed to me the stock 02's wern't very accurate to begin with. More succeptible to temperature changes than fluctuations in air/fuel mixtures.

I'm not trying to say I am right. I'm genuinely interested in learning more on this subject.

I altered my 02 harness, on the sensor itself, a year ago via 12 inch extentions of 16 awg (if memory serves), and noticed no change in the readings on my scanmaster.

 

The O2s draw reference air from the space between the wire and insulation (like a straw). This reference air is what is used to compare to the exhaust oxygen levels. Altering that can affect the air the sensor gets and therefore could cause skewed readings. Notice I said could-not will. I just feel it is better not to add any possibility of compromising the sensors function. The sensor also uses stainless wire-an indication of how important the integrity of the wire is and how long it will last.

You say that you believe that the O2s are not very accurate to begin with. IMHO, that would be a good reason not to disturb the wiring, that would have the potential of making them even less accurate.