Driver's Side Sensor Under Manifold, What?

Hello friends, while changing out the head gasket on my son's '92 XJ (4.0L, AW4) I noticed a sensor on the engine block about center under where the intake/exhaust manifolds bolt up. The wires are fried/melted and it doesn't lead anywhere, there does not appear to be a place it could connect to on the lone nearby wiring harness (which I believe is the oxy sensor) Is this some sort of optional pre-cat oxy sensor fitting that was installed to plug the hole in the block for it but not hooked up because the manifold doesn't have a bung for it? I don't know the year by year breakdown for pre and post cat oxy sensors off the top of my head and a search didn't give me any decent results. If this is a necessary sensor, changing it out now makes the most sense while I have easy access. Any help would be appreciated.

Doug

I would imagine it's the knock sensor.

Was that an optional sensor on the '92 model year? I didn't have a check engine light and there doesn't appear to be a place for the wire to plug-in. Is it typically in the exh manifold? It looks like it's been burned/dead-ended for awhile.

OK, a search using "knock sensor" tells me that it is a pretty worthless sensor and the fact that my XJ was running fine with it hanging loose and ratty looking means I'm just going to leave it alone. Thanks for the heads-up what it was.

There's no knock sensor on an HO era engine . What I believe it to be is the sender for the temp gauge, if you have one, or for the idiot light. In addition to this one, there's another temp sensor at the T-stat housing, which tells the ECU to run the electric fan. With the wirer being fried or otherwise not connected, how was the gauge or warning light behaving? There's got to be a piece of wire nearby that wants to be connected to it, so keep looking!

Temp sensor/sender for the gauge panel on that era should be on the top rear driver's side of the head.

did someone swap in a renix block? does it have peices of green plastic showing from the damaged part? everything you say, leads me to think knock sensor (renix only).

It does unthread, it only threads into a blind hole, so dont worry about plugging it.