91 tachometer problems
 

I have a 91 miata with a 99NB guage cluster everything seems to be working EXCEPT my Rpm's They dont work at all. The only reason I can think for this is because 91's get there tach reading from the ignitor where as newer models get their readings from some sort of module....Any suggestions?
This is how I have it wired right now:
91 (from Dash) - 99 (from cluster)
Ignitor (Yellow/Blue) - Green/Orange
Ignitor Switch (Black/Blue) - Violet

My only suggestion is to put in an NA cluster.

I hate to do that when I've gone through the work to do the entire Nb interior swap the guages just top it off...
Does anyone know where the 99 gauge gets it's signal from maybe I can just run a seperate wire to the guage?

99 = digital speed sensor
91 = speedo gear cable

He said tach.

yea I already swapped the speed sensor to digital.

oh yeah.

ok tell me what yall think this is what Ive came to the conclusion after searching and searching...
This is a chart I found of colors.
Wire colors. The tach signal is the same color at the ECU.
Ground Power Tach signal
1990-93 Black (2D) Black/yellow stripe (2K) Yellow/blue stripe (1H)signal
1994-97 Black (2D) Black/yellow stripe (2K) Black/white stripe (1H)signal
1999-05 Black (3J) Black/yellow stripe (1C) Green/orange stripe (2K)signal

You would think yellow/blue goes with green/orange well that didnt work, and I dont have a black/white..

So I found the attached picture of the ignition ...
http://www.sonny2.com/images/car/draw2.jpg
So If I ran a wire from the black/white, and connected the three colors (yellow/blue, green/orange, and black/white) together into one that it would work?