4beginner

Some advice please.
I’m swapping a 1990 3VZE into my BHG 1993 but the connector/wiring for the 2 knock sensors are different. I have read a thousand post/ articles about this but still cant work out why the 93 has a black (active to ECU) and a brown (earth?) wire and the 90 has a black (active to ECU) but the puzzle is the shielding wire (also starts out as a black wire!) that surrounds the black active wire and seems to connect up into the loom with other shielding/earth wires.
My question please = Can anyone confirm that I should connect the black wires together and then separately the brown with the shielding/earth wires? Toyota say that all 3vze knock sensors are the same so will this work?
Many thanks. Mitch

MudHippy

All 3VZE knock sensors are the same, both types, 88-91 and 92-95. They don't look the same, or have the same connectors, wires, or part #'s(2 different part #'s for each sensor and wire, 4 total). But essentially they're all the same. The sensor wires have different connectors and shielding wire arrangements though. However, the sensors themselves are interchangeable as far as both types fitting any year 3VZE block, and being electronically compatible with any year's ECU. All they changed was the shapes of the connectors on the sensor, sensor wire, and ECU wiring harness. And apparently the way the sensor wire is constructed shielding wire wise too. I didn't know about the shielding/earth/ground wires being different thing until just now.

So to answer your question, yes. To make the older sensor work with your later wire/wiring harness, just make sure that the sensor signal wire to the ECU solidly connects to the wire connector terminals on both ends of the sensor wire in some fashion(i.e. splicing wires, reconnecting the wire directly to the other terminal, or maybe even just swapping the signal wire w/terminal still attatched between connectors on the sensor end and then splicing the shielding/earth/ground wires). The shielding/earth/ground wire may not even "need" to be there at all. Since it already is, you may as well reconnect it too. It isn't needed to make the sensor function though, since it doesn't even connect electronically to the sensor itself(or rather, doesn't complete the earth/ground circuit to the ECU through the sensor housing and engine block). But if Toyota thinks it needs to be there, for whatever reason, then so do I. I sure would like to know why, but we may never know the answer on that one...or why they eventually changed the design of it. Who knows? I do know that the one on my 88 is in pretty sad shape, but still works just fine. Both the wire and the sensor are the originals as well.

4beginner

Wow thats exactly what I was hoping to hear thanks muddy!! I amm constatly being surprised at how tricky Toyota can be when you thing you have a simple solution sorted out.
Ill solder another waterproof connector into the loom to replace the old connectors as they are truly stuffed. I cant wait to get the engine back in so I can go fishing again in my old banger (I call it Harvey).
Many thanks again. Cheers Mitch

4beginner

Incase anyone is thinking of swapping loom/engines and the Knock Sensor wires, well soldering the wires as suggested above worked just fine.
Thanks again Muddy for your advice. Cheers Mitch