1996 RMW mystery wire

As I wait for the block to get back from machining, I have been doing all the the other stuff, including starting on cleaning up the oil soaked harnesses, which is pretty much everything blelow valve cover height.

When I opened up the lower right engine harness by removing the loom so I could clean up the oil and give the connectors a good cleaning, I ran across a wire in the loom that really isn't obvious where it could go.

It is a green signal size wire that is in the area of the starter wiring breakout and the knock sensor breakout.

It doesn't show any signs of being torn out along the way as the insulation is stretched like some other show, it isn't stripped and is without a connector of any kind.

The only wire close to it is the single wire to the connector for the right side knock sensor.

The FSM wiring diagrams suck trying to find anything, even if you know what it is for, but they do show a coolant temp sensor in the block right there, which I don't recall seeing or removing and can't find in the manual anywhere.

The only thing I can think of is that it may be an orphan that was part of harness and left over from OBDI setup the previous year, or maybe the knock sensors used to be two wire?

Anybody got a clue what it may, or may not, be?

Passenger side temp sender that goes in head, sends signal to the gauge on the dash. The other sender is the one on the water pump, that is the important one that gives info to the PCM.

It might be the wire used at the factory to prime the fuel system before first vehicle start. It has no use after the engine has started once, and it not called out in the FSM.

If Rev is talking about the fuel pump test lead, then no, that is up higher, and the wrong colour.

It is for the coolant sensor, which I finally found in the wiring diagram for the dash and cluster. I had looked at the sensor, but it was two pin so I didn't think it could be it as I only had one wire.

Found the connector stuck in the ball of aluminum face insulation that was on the harness with the remainder of the green wire, but didn't do much as the wire was scorched pretty well and must have broken when unplugged, sticking to the tape or snagged and broke during the pull of the engine.

Yes, super common with that wire/connector. Extend it, new sensor, new connector, new shielding.

BTDT, more than once.

jayoldschool wrote:

Yes, super common with that wire/connector.  Extend it, new sensor, new connector, new shielding.  

BTDT, more than once.

This car probably had work done in that area shortly before I got it, as it had a new radiator in it and looked as if the it had been acid cleaned when I took the block apart this year.

It had original plastic loom on the wire, then the stick on foil faced insulation, then a maybe 3/4" diameter light aluminum corrugated piece of tubing around it, held in place by melted electrical tape.

Do you have a good source for the foil faced, looked like rubberish, insulation and small sleeving. Most I have seen are the flexible jacket stuff, although that would probably work also.

The aluminum corrugated piece is stock. When I redid my wire the second time, I used a good wrap of the adhesive aluminum tape that is used for sealing metal ducting. Not "duct tape", lol. Another good choice would be a section of the insulation that's on the AC line.

I would just put a patch in the wiring, and use the original sensor, and connector. The original sensor uses a center lead (gauge), and an side lead (idiot light) making the connector similar to a 3 pin. You can get heat resistant aluminized tape or a small heat shield at your local parts store. I wrap/sleeve everything that gets within 6 inches of anything exhaust related.

Fred Kiehl wrote:

I would just put a patch in the wiring, and use the original sensor, and connector. The original sensor uses a center lead (gauge), and an side lead (idiot light) making the connector similar to a 3 pin. You can get heat resistant aluminized tape or a small heat shield at your local parts store. I wrap/sleeve everything that gets within 6 inches of anything exhaust related.

That is pretty much the intent with it all. Some of the loom in hot areas is as brittle as glass, so will need to be sleeved and/or insulated, I think.

How many spark plug boot 90* aluminum covers did they come with? There were 4 on this engine.

I believe 4 is the standard number. They go on each side of the downward sections of the manifolds. Some fiberglass boots would be good for the rest.