Electric speedo problems

[B Schein]

I am trying to hook up an Autometer electric speedo. The car has a tune port motor with street and performance harness and computer. There is a green wire that comes out of the harness label VSS 4k pulse. I Got the gages from Covans with the dash insert so everything was pretty much pre wired with an American Autowire harness. On there body side harness there is a yellow and purple wire. The yellow wire is labeled VSS ground and the purple is VSS signal. As far as I can tell you only need to use the Yellow wire if you are using an autometer haul effect VSS sender. The directions form the speedo say it should work with a sin wave single from 500-400,000 pulses per mile the computer should be putting a 4000 pulse sin wave so it should work. I hooked up the green and purple wires followed the calibration directions and the speedo doesn’t read any thing any one have any Ideas.