240z Tach

[240zBoy]

I'm trying out the tach adapter from msd to get this baby working on my 72. There is another topic that sort of talks about it but I got a quick question it did not cover. Where exactly is the tach inductive loop that has the green/white wire and the black/white. Is it that mechanism by the original coil with two larger wires going to it or actually behind the tach. Help would be awesome as I'm in a pickle and can see both these colored wires (a couple b/w actually) in both places.

-Thanks

[Zmanco]

The tach's inductive loop is on the back of the tach. The loop's wires both go into the 4 pin connector. Post a picture and I can help you pick them out.

[240zBoy]

I can try to get better pics if these do not show it.

[Zmanco]

The inductive loop is the white wire that is looped on the right side in these pictures. There should be a screw/clamp holding the looped part to the back of the tach IIRC.

[240zBoy]

The inductive loop is the white wire that is looped on the right side in these pictures. There should be a screw/clamp holding the looped part to the back of the tach IIRC.

 

So according to this post http://forums.hybridz.org/index.php?showtopic=37376 . I should run the red wire to the white wire on the right? I am really confused

[Zmanco]

This was not my post so take what I'm suggesting with a grain of salt, but I think this section below is referring to the wires near the coil under the hood on the driver side fender:

Remove the 8920 tach adapter from the package. Throw away the instruction sheet. Neither diagram applies to the Z.

 

It has four wires coming out of it:

 

Black - ground

white - trigger

Red - option1

violet - option2

 

Now, to get the tach working:

 

1. Take the black/white wire near the coil, and hook it up to an ignition switched 12V (hot when key is on).

2. Run the RED wire from the tach adapter and connect it to the green/white wire.

3. The white wire from the adapter goes to the MSD's tach output.

4. The black wire goes to ground.

 

I don't think you want to be doing anything with the coil on the back of the tach.

 

It's been years since my car's ignition was stock, but I'm pretty sure the black/white and green/white wires were originally connected to the two terminals of the coil. You probably removed them when you installed the MSD ignition box?

[240zBoy]

I might be in luck though if this is what they all are talking about. They meet the color requirements and kind of do a loop lol.

[Zmanco]

He is saying that those two wires go to the loop on the back of the tach. Normally the loop is in series (spliced into the circuit) that controls current through the coil. The MSD box takes over supplying power to the coil so something has to replace that function in order to get the tach to work. The MSD tach adapter is doing that, hence the need to connect it to the wires that used to be attached to the coil.

 

BTW, there's no need for the resistor on the fender any more. Simplest thing is to just use some #16 wire and the appropriate connectors to create a jumper across it.

[240zBoy]

He is saying that those two wires go to the loop on the back of the tach. Normally the loop is in series (spliced into the circuit) that controls current through the coil. The MSD box takes over supplying power to the coil so something has to replace that function in order to get the tach to work. The MSD tach adapter is doing that, hence the need to connect it to the wires that used to be attached to the coil.

 

BTW, there's no need for the resistor on the fender any more. Simplest thing is to just use some #16 wire and the appropriate connectors to create a jumper across it.

 

Okay. So which black and white wire do you think he wants to get 12v. I would guess the larger one in that picture but it was not connected to the coil