MSD 6A

[S Schroeder]

Hi all-
I FINALLY have a pretty sweet running 914. I Increased the size of the idle jets, installed a comp-u-fire in place of the points, and an MSD 6A. Really fun to drive. Thanks to those who replied to my last volley of questions!
So, I'm down to one last issue - the tach. I installed the tach adapter but my once perfectly operating tach now either bounces or does not work at all. The symptoms are worse when the headlights or other bigger electrical draw happens (fogs, turn signals) are on. There is a diode included in with the tach adapter which the instructions say "may be needed on some models" but when I install it the car won't start. Any of you using the MSD have any suggestions? Any help is GREATLY appreciated.
Thanks!
Scott Schroeder
Denver, CO

[mikey]

Are you sure you have the diode in the right way? They are polarized.

Mike

[John Rogers]

I had to dif out my MSD info and I found there are several things to make sure of/check: First of all as delivered the diode can only be hooked up one way due to the connectors. There should be 4 wires connected together at the negative side: MSD white, Blk/Purple to tach, Black from distributor and a wire from 8910 unit. Make sure this assembly DOES NOT contact the negative side of the coil. On the other side there are also 4 wires: red from distributor, MSD small red, red +12volt from key and a wire from 8910 unit. Also Make sure this assembly DOES NOT contact the positive side of the coil. There should only be MSD orange to coil + and MSD small black to coil -. Finally make sure all the MSD wires are loose and NOT bundled tightly together as the high frequency will cause ghost currents and voltages which could make the tach jump. I did not use the diode as I installed an Autometer memory recall tach but it worked well before I switched. Good luck.

[Ian Cubus]

I have the same MSD and didn't use the diode. You are right it won't start! Ha-ha! You don't need it.