Where can I hook the signal wire for a Tach ? I have a 1992 Samurai and I tried the negative side of the coil but the Ignitor seems to interfere with the signal.

Doesn't the signal wire to go the positive side of the coil?

Doesn't the signal wire to go the positive side of the coil?

I thought it went to the Negative side? Atleast thats what the instructions say LOL

Might be.  I just did a quick search and one set said negative side, one set said positive side.  It's been forever since I hooked up my Tack, I'll check it out this weekend if nobody else has jumped on. 

It should be the negative side.  It is the brown/white off the coil....or did I use the brown off the noise suppressor filter.  Hang on, I'll go look....

yeah, I tapped the brown/white wire coming off the coil for my equus tach in my 91.  I guess if that doesn't work for you, you could try the brown off the noise suppressor.  The brown wire is what runs to the instrument cluster, for a tach input.