CS_AR

In checking out the front Crankshaft Position Sensor wire and cleaning up and repairing the old wiring harness insulator, I found a 3rd wire inside the wiring insulator next to the white and black wires. I don't see this wire referenced for the CKPS.

Is the wire supposed to be connected as a ground or should I ignore it?

Here is a picture of the 3rd and exposed wire in the picture below on the right. The twisted wire is the extra wire.

The wire on the left is the oil pressure sensor switch wire and plug.

Nismo_Pilot

iTrader: (1)

Is that the signal wire? If so, it should be a shielded wire that needs to be grounded. It keeps noise out of the crank signal.

CS_AR

I looks like some type of a grounding wire. It is actually a bare silver wire under the black plastic jacket that is twisted around the white and black wires that go the CKPS plug.

Since that silver wire is exposed under the black jacket and wraps around the insulated black and white wires, it reminds me of the outer wire shield on a RG62 93 Ohm coaxial cable for an SNA network connection. The outer shield had to be grounded to the CPU frame or switch device for the network work correctly.

Should I ground it to the engine or body?

I'm surprised this bare wire was twisted around the black and white wires without a lead to anywhere. It just dead-ended under the insulator. I haven't looked at the I30 to compare but I don't remember anything other than the white and black wires that connect to the CKPS plug. I guess it is like having a house wired for three prong 110 outlets with a white, black, and ground wire, but the ground wire was never hooked to anything that was actually grounded. Yikes! I can see how it would work better if it is actually grounded.

CS_AR

I think I found the answer in a thread on CKPS and post from Dennis below.

http://forums.maxima.org/4th-generat...ml#post8953441

Here's the question:

Does the bare wire that appears to be wrapped at a 30 degree angle around the other wire under the black outer jacket in the picture above accomplish a dual purpose?

1) Provides an insulation (shielding) layer between the two long CKPS induction wires to reduce interference -- especially as the sensor wires age and the outer plastic covering may begin to fracture and develop micro cracks from years of heat and vibration.

2) Increases the stiffness of the CKPS (black and white) insulated wires within the black jacket to make them less vulnerable to damage from a sharp bend or twist.

I found some information on wire wrapping at a 30 degree angle can be used to increase structural strength while allowing the wires to bend and flex as needed for support.

Org thoughts?

DennisMik

iTrader: (2)

I believe that the mystery wire in your first photo is the shield for the transducer signal wires. As long as the shield is connected to ground at one end, it will do its job. From a perfectionist's point of view, you don't want any signal wire to extend out past the shielding as that creates a spot for interference to get in.

But the little bit of wires that extend out from the shield on the crankshaft sensor probably isn't going to be a problem. The frequency that the crankshaft senor wires carry isn't that high compared to the TV, cellphone, radio signals, where the higher frequencies are more susceptible to interference.

But Nissan thought that there could be some problems in some way from something, otherwise they wouldn't have used the more expensive shielded wiring. And sometimes the problem is that the interference comes from the part we think might need the protection. It could be the part emitting interference that creates static on grandma's TV and gets her upset.