VS V6 Series 1 O2 4-wire earth issues ?

[OZ38]

I had a search around but did not find it.
But I am sure you guys would have discussed the VS V6 Series 1 Commodores 4-wire O2 sensors heater earthing issues ?

Is it really a known problem from Holden ? I was reading a how to on JC to splice into the ECU pin out earths & ground to the body.
Has anyone found where the original problem occurs in the loom ?

Cheers

[pman92]

I'm 90% sure the real problem is usually one of the earth points on the engine (I think the one at the driver side front on drive belt tensioner?)
The best solution is to splice in and add a good earth directly to the O2 sensor wiring I would say

[The1]

this was it i believe.

[immortality]

The quick fix was to cut the heater wire for the sensor that was playing up.

The wiring diagram shows that one of the O2 sensor wiring looms has a link between the sensor and heater earths. What I did on our old VS was to splice both heater earths directly to the engine which seemed to do the trick. I think I tried cleaning all the earth points but did not see much improvement.

[OZ38]

The quick fix was to cut the heater wire for the sensor that was playing up.

The wiring diagram shows that one of the O2 sensor wiring looms has a link between the sensor and heater earths. What I did on our old VS was to splice both heater earths directly to the engine which seemed to do the trick. I think I tried cleaning all the earth points but did not see much improvement.

My old VS always smells like it is running very rich (especially at idle). I will try cleaning those earths but if I feel there is no change I might try splicing into the O2 heater earths like you did.

[immortality]

I made up a small patch loom using a couple of old O2 sensors and a couple of plugs from another loom I raided at the wreckers so that I didn't have to cut the actual loom.

Fitting new O2 sensors, patching the loom and then fitting some later style 777 injectors was the best thing I ever did for fuel economy on the old VS.

[OZ38]

I made up a small patch loom using a couple of old O2 sensors and a couple of plugs from another loom I raided at the wreckers so that I didn't have to cut the actual loom.

Fitting new O2 sensors, patching the loom and then fitting some later style 777 injectors was the best thing I ever did for fuel economy on the old VS.

Can you draw how you did the patch loom ?
I intend to change the O2 sensors so would end up with two I can bastardise.

[immortality]

Sorry, completely forgot about this. I don't have a wiring diagram, the only thing I still have is a pick of the completed patch loom.

O2 interceptor wiring plug.jpg

This is the last version I made. I fitted one in each side and extended the earths for both sensors so they were earthed at the same location on the block and then wired the heater earths together on a different part of the block.

The unused tails are wrapped up inside the loom to make it look tidy but they are isolated and not connected.

[OZ38]

Thanks for that.

[bignutzzz]

from what i can see in the vt diagram, the sensor earths for both banks run back to the ecu without any splices(d14 and d16). but for some reason in the vs, the right sensor is spliced with the heater ground. Does anyone know why it was this way for the vs?
would it be as simple as disconnecting the sensor from this splice and running it to the ecu like its been done in the VT diagram?

ive got my loom stripped back at the moment, was thinking i could fix the issue while im at it.