VS V6 Series 1 O2 4-wire earth issues ?

[immortality]

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?

That is the million dollar question.

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.

If you can find where the splice is then yes, just remove it and solve the issue. I'd be keen to know where that splice is hidden.

[bignutzzz]

theres 3 splices in about 50cm from the firewall plug, they all seem to go to either 1 of the 3 splices there. im trying to make sense of it all

[bignutzzz]

both my sensor earths are seperate. they meet at the ground terminals both sides. is it possible this issue was fixed? or perhaps the wiring diagram is wrong?

[immortality]

Unsure TBH. Our VS had the issue and I was fairly certain it was a series 2 model. We identified the issue by cutting the O2 heater wire on the old O2 sensors and seeing what it did. Then I fitted new O2 sensors with modified wiring with the interceptor loom as shown on the last page.

[bignutzzz]

Unsure TBH. Our VS had the issue and I was fairly certain it was a series 2 model. We identified the issue by cutting the O2 heater wire on the old O2 sensors and seeing what it did. Then I fitted new O2 sensors with modified wiring with the interceptor loom as shown on the last page.

sorry i forgot to mention this loom im working on is a vs l67 loom.
the 3 splices there are as follows.
Splice 1: right sensor earth/d14/grounding ring terminal
splice 2: left sensor earth/d16/grounding ring terminal
splice 3: Maf/both heater grounds/grounding ring terminal. the wire that runs back to the ecu. before it hits ecu theres another splice
splice 4 (inside car): runs to splice 3/opposite grounding ring terminal to splice 3/ and 4 wires that run back to the ecu connector plugs (not confirmed a1 a2 b1 b2).

hopefully of help to someone in the future.

[immortality]

I'm no wiring expert but that seems like asking for trouble and potential for ground loops?

I'll be doing some tuning on a VS L67 in the next few days so I'll see how the O2 sensors behave, I don't think it has had the O2 sensor wiring modified in any way. It has however had a engine swap so it would have had all the factory earth points cleaned when it was put back together.

[bignutzzz]

I'm no wiring expert but that seems like asking for trouble and potential for ground loops?

I'll be doing some tuning on a VS L67 in the next few days so I'll see how the O2 sensors behave, I don't think it has had the O2 sensor wiring modified in any way. It has however had a engine swap so it would have had all the factory earth points cleaned when it was put back together.

me neither. this stuff is sending me cross eyed tbh. the reason I've got my loom stripped is because I was getting high resistance though a couple of splices which led me to believe the factory electrical tape wasn't enough to keep the moisture out of the connections. perhaps a common issue.

I could isolate both sensor grounds by just giving them their own ring terminal I guess. I've no idea if that will have any benefit though. well over my pay grade on this one.

[immortality]

I think the main thing is the split out the high current from the heater circuit leaking into the low current sensor circuit.

[immortality]

I just hooked up my mates VS L67 (factory) and the RH sensor readings are troubling.... Very lazy and huge discrepency between the LH and RH sensors.

[immortality]

LOL, that O2 sensor is killing the car. Sent him away to get it fixed before we can do any more tuning work.