Tachometer Wire to MSD Converter

[AZGhost623]

I need some help locating the tachometer wire under the hood, so I can reroute it to a MSD converter for my XDI setup.  I have read a few things, but they have me second guessing its right. I have read that the TAC wire is the 1st wire on the Ignition Control box? I have also read that its off over by the coil attached to the ballast resistor; and/or its the green wire off the distributor? Can someone clarify who knows?

I did download the FSM, and the electrical circuit doesnt make sense to me. Its on page three, right in the middle. Im not sure how to interpret the diagram, as the wiring for the tach goes no where?

 

for a 76 280Z thanks guys!

 

 

 

Edited January 4, 2013 by AZGhost623

[NewZed]

Check out this diagram that a user on classiczcar worked up - http://www.classiczcars.com/forums/thread36494.html  or go directly to his site - http://sridout.com/datsun/76circuit_COLOR.pdf   It's very nice.

 

The wire is blue, it comes from the coil (-) through a lug on the ballat resistor and it branches off to Pin 1 of the ECU and the tachometer on the way to the ignition module.

 

The tach wire will have a small black inline resistor.  You can feel it or see it in the bundle of wires by the relays under the dash.  It's about 3/8 x 3/4" in size, rectangular, and has a male and female bullet connector.  Probably easiest to peel it out of the bundle and tap in to the line there.  Don't forget to unplug the stock module for your XDI.

[AZGhost623]

hmm those links you gave dont work. But I know exactly the wire your talking about! So the blue wire off the ballast goes to the ECU/IM stuff, but it doesnt go directly to the Tach? So If im going to wire it in, the output side of the tach adapter goes to the blue wire, and then Ill need to wire it up to the tach from the Ignition module area? (i know of the blue wire over there as well if thats it) The EFI harness and ECU are pulled completely out. The ignition module is also gone since this is a triple carb setup now.

 

Thanks for the wire locating! Here is my engine bay pix so far...lots more wiring to do.

 

Edited January 5, 2013 by AZGhost623

[NewZed]

I don't know what's going on with the links.  The web address is right in a new window but it doesn't open the page.  Maybe it's the forum blocking viruses.

 

If you put this - "wiring 1976 saridout site:www.classiczcars.com" - in the Google search box, the link will come up as the third hit (unless this post knocks it down).

 

The blue wire does go directly to the tach (the branch with the inline fuse).  And the module and the ECU. Three branches from the coil negative post.  Aseparate harness from the EFI harness, I believe.  An ohmmeter will tell you if it's the right one.

 

Test - http://www.classiczcars.com/forums/thread36494.html

[AZGhost623]

sweet, that worked...

 

thanks!!

[AZGhost623]

tac is still dead. We got the engine finally started, but will need to figure out why the tac isnt working. Im positive its hooked up right to the XDI with the tac adapter, but unsure if I have the right lead now off the existing wiring harness. I did find the lead you mentioned, and thats what I used.

 

On a side note, how do you check the timing on the XDI? There are two brass holes I assume is where you check it  at. What voltage do you put the ohm meter at? It shows 0 no mater what I do.