[22GT]

Second thing is I was under the impression the pink wire should not be cut in the middle. So if I were to "cut between the ignition switch and the quad plug, and put the connectors there" it could possibly cause a problem, right? I'm NOT saying you're wrong 22GT, there's just so much conflicting info here and I really want to understand how to do this in a way that will work.

Electrically it would make no difference whatsoever, and it would be much easier to splice there than in the pink wire. Splicing in the pink wire at the end is annoying enough, but if you sliced into the the middle of the pink wire, it would alter the electrical effect.

Bottom line- No toucha da pink wire.

 

[SebringSixSpeed]

Ok, I didn't understand exactly which wire you were referring to "between the ignition switch and quad plug" because my pink wire runs between the ignition switch and the quad plug as seen in the pics. Now, I think you mean I should splice into the green wire with red stripe (that is paired to the pink wire at the switch in my picture).

If that's not right, then what color wire am I splicing into from the back of the switch?

 

[Phantom II]

Now in the diagram above it shows the tach being 'inserted' into the resistor wire however it does not state where this is done (ie no dimensions).
NO! It is not "inserted"!



Perhaps it is not critical and that is why Slim's setup works just fine even though its not truly like the diagram.
His connection is at the wrong side of the resistor, so his tach reads lower than actual rpm.

Electrically it would make no difference whatsoever, and it would be much easier to splice there than in the pink wire. Splicing in the pink wire at the end is annoying enough, but if you sliced into the the middle of the pink wire, it would alter the electrical effect.

It’s been a long time since I’ve opened a basic circuits or physics book but my recollection tells me that this discussion is about a simple series circuit. A current sensing device (the tachometer in this case) will read the same regardless of where it is “inserted” (Ford’s term for breaking the circuit to create a series installation of the tach) in the circuit. The current in the circuit is constant at any particular instant at all points in the circuit. If we were considering a voltage sensing device it would be installed in parallel across component(s) that develop a voltage drop when current flows through. A voltage sensing device would have different readings depending where it is installed in this circuit.

A note about the resistance wire: The resistance wire could be cut into any number of segments and installed at multiple locations as long as its effective length is unchanged. The current through the circuit would be the same as if a single longer piece was used. In reality the resistance wire would lose some effective length at each splice. Where the resistance wire overlaps “normal” wire it would cease to function as a resistance wire. That would have to be taken into account to maintain the same performance from multiple pieces.


Slim’s method of adding a copper wire loop to make an accessible connection under the hood should be fine. The change in resistance to the total circuit is probably negligible from adding a few feet of wire and would not reduce the current sensing tach’s reading by a noticeable amount (this is regardless of where it is spliced in series into the ignition circuit). Knowing the maximum current flowing through the circuit would make it easy to calculate the percentage of change in current flow caused by adding a few feet to standard (14 gauge for example) copper wire to the circuit.

 

[SebringSixSpeed]

After thinking about all the info provided here and elsewhere I have decided that it will be simplest (and most like all the diagrams I have seen) to disconnect the pink wire from the terminal at the switch, add a copper pigtail to the switch in the same location where I remove the pink wire, then put the tach in series between that pigtail and the pink wire.

 

[SebringSixSpeed]

Here is the picture of the multi-strand pink wire as promised, doesn't look too difficult to crimp or solder but we'll see.



Here is the back of the ignition switch just like the wiring diagram in the service manual, pink and green/red terminated together.



Here is the other end of the pink wire terminating into a quad plug coupled with red/green