Tach waring question

[67vertman]

I just got through changing my standard dash to a Ralley dash, I am running an MSD ignition and EFI ECU. The white wire from the MSD is running to the ECU, do I run the tach wire to the MSD white wire or directly to the negative side of the coil? 

Thanks,

[Moparal]

Msd has all their dirrections on line, but the white wire if for points when running specific settings. IT ISNT USED IN ecu THAT i KNOW OF. I know when I run a crank trigger and retart box, the white wire is hooked to the retard box. are you sure it doesnt go to the box itself? tach wire that is.

[67vertman]

It has been a couple of years Alan, so I am not sure what it conencts to on the ECU...I thought tach.  I will have to check, thanks for the reminder that it is on line, my old brain didn't remember that.

[67vertman]

All right Alan, I checked MSD website, and you are correct the white wire is for the crank/didtributor trigger, i should have remembered that  .  There is a tachcometer port on the MSD unit.    I will try that, it says I may need an adaptor, if the tach dosn't work correctly. 

[maddawg57]

I'm running a Msd 6A and MSD dissy, and had to use a adapter for the tach to read right

[67vertman]

I'm running a Msd 6A and MSD dissy, and had to use a adapter for the tach to read right

Thanks Maddawg57, I am running the MSD and Mallory Dissy but through an FAST ECU.  Did you run you tach wire straight from the MSD?  I am going to give it a shot, and if it doesn't work I will contract MSD and get an adapter.