early 240z tach problem

[CORPCRIM]

Here is my dilemma.

 

I re-wired my 12/1970 using the EZ-Wiring kit but I didn't hook up the tach because every wiring diagram I've seen talks about a green wire on the back of the tach. There is no green wire on my tach. Only a black wire, a yellow/red wire, and a white loop with black and red markings. Can someone help me figure out how to wire this up?

 

Does the Black wire go to a ground and the yellow/red wire go to the coil?

 

[Six_Shooter]

The yellow/red is ignition, as in 12V switched ignition.

 

The black is ground.

 

The loop is a current sensing circuit, that will need to be ran as a loop from the dizzy through this loop and back to the coil IIRC.

 

Mine used to be like that, until I put a points type tach in.

 

If I recall the EZ wire kits, they assume a points trigger to the tach, and would likely be easiest to replace your existing tach with one from a 260 or 280Z.

[Geking]

yep. Six is right. I would just do a gut swap with a 280z tach. Its not too hard if you just take it slow. The foam pads at the back may have stuck a bit to the metal casing when you attempt to remove the guts. I had to do this for my 73, as they are not easy to find. (73 uses a 240z case with the 260 and 280z style pickup. The pickup is a single wire coming from the - side of the coil. If your tach jumps all over the place and will not go above 3k, add in a resistor inline. (I have forgotten the exact rateing, somewhere like 4K I think, only 1/4 watt should be fine)

[Six_Shooter]

yep. Six is right. I would just do a gut swap with a 280z tach. Its not too hard if you just take it slow. The foam pads at the back may have stuck a bit to the metal casing when you attempt to remove the guts. I had to do this for my 73, as they are not easy to find. (73 uses a 240z case with the 260 and 280z style pickup. The pickup is a single wire coming from the - side of the coil. If your tach jumps all over the place and will not go above 3k, add in a resistor inline. (I have forgotten the exact rateing, somewhere like 4K I think, only 1/4 watt should be fine)

 

My '73, had a current sensing tach just like above.

 

There seems to be conflicting information on this, but it seems that most '73s had current sensing tachs.

[wheelman]

My 73 also had the current sensing tach.

 

Wheelman