88' Carb'd Distributor wires

[wflaw45]

I am trying to get my B6 carb'd swap with MSD ignition to run but not getting signal from disty for some reason.

I know the Black/white wire is "B" and positive
and the Blue "C" wire is negative.

does anybody know the purpose of the third wire "A" that is blue and orange? from a diagram i know that it goes to the computer but its purpose i dont know. any and all help would be appreciated

Thanks
-W.F.