5th O2 sensor wire?

[Iggy]

Today went to replace my O2 sensor and was surprised to find a 5th wife in the loom before the 02 connector. I can't find the other half of it, but I'm guessing to goes some where? doesn't help that the insulation is gone.

 

[G]

That's a ground.

 

[Iggy]

A ground for what?

 

[G]

Or shielding, I forgot.

 

[mjdarg]

Yea, that looks like shielded that is in the harness under the heat shrink.

 

[iceman69510]

Agreed, that is the shielding wire.

 

[FlyingEagle]

See the diagram in the site thread below.

Click for GVR4 thread

It's a big fanout sheet for 4g63 type wiring. Pins with the little circles drawn around the wires, for the 02 sensor and the knock sensor are a shared shield setup; open an unattached at one end, connected at the other, but not part of a circuit - just noise/RF rejection, likely only could be causing by radios/plugs/etc.

I just build a little harness to replace my current one should anything in it go bad, and I had my hands on those wires first hand. The other guys before me, nailed it!