Oxygen sensor

[lucas83]

Hey guys made a huge mistake, the rookie that I am I cut the wrong side off of the o2 sensor(plug side with green wire coming from inside car) noticed after that I can soder it because it's actually 2 wires into one, anybody have an idea of what I can do to get it reconnected? Or if there is a way to bypass it or get a new wire?

[RRoller123]

A little confused, can you post a pic of the damaged one?

[lucas83]

[kilrwail]

Normally, to replace an O2 sensor, you must replace the sensor and its plug as an assembly. If this sensor was not faulty, it is now! I don't think soldering is feasible.

[lucas83]

Not sure what I can do here, maybe follow backcto ecu? And make a new wire?

[So Cal Mark]

that's a single wire sensor, what you see as a second wire is the shielding around the inner wire

[lucas83]

that's a single wire sensor, what you see as a second wire is the shielding around the inner wire

Ok so I can just strip it back and connect with a soder and it should be ok?
Thanks again guys for the quick reply really appricate it

[RRoller123]

Try to get the shielding reconnected as well.

[klweimer]

As I recall, the shielding on the outside of the cable does not attach to anything on the O2 sensor end of the cable. The shield is only grounded on the ECU end. So you would just clip off the excess wire and make sure it doesn't touch the inner wire when you solder on a new quick connect terminal.
Kirk

[RRoller123]

I wonder why they would do that, maybe they just need localized shielding at the sensor? I used to work with the RF guys in the UL/CSA/ISO compliance Lab, but I didn't learn enough from them to be able to answer that.

[aj81spider]

In many (most?) applications shields are only connected at one end to prevent ground loops. The shielding function is accomplished because the shield is connected to ground at one end, so the shield is at ground potential and will protect the wires inside from external fields.

You don't connect both ends because in a system like a car there can be differing ground potentials in different parts of the car. When you connect the grounds together willy-nilly (that's a technical engineering term) you can get current flow from one part of the ground system to another because of those different potentials. Current flowing in the shields is not a good thing and can be the source of noise - the opposite of what shielding is trying to do.

A well constructed ground system will be a network where there is only one ground path from any point in the system back to the main reference point.

[RRoller123]

Excellent, that settles that!

[lucas83]

ok so strip back the outer wiring and soder/connect the inner ones together? Cant thank you guys enough, totally saved me from a huge issue. Thanks

[RRoller123]

AJ: In our various manufactured computer chassis', the entire box was a ground envelope? Used copper tape, gizmos with barbs, etc. at all the sheet metal joints to stop leakage.

[aj81spider]

Hi Pete,

You're right. In that situation the chassis is effectively the shield and needs to be at the same potential and continuous. You'll find that inside the box there should be (if designed right) single path grounds from all the boards to the power supply.

The analogy to the car situation would be if you had several boxes all shielded you would want to connect each to a common ground point with a single wire and you wouldn't want to have shields between the boxes connected at both ends or you might get current flow between the boxes on the shield wires.