Tach wiring help...sort-of

Ok got a MK4 2.0 that we're building. Put in a new Auto-meter tach, set it up for a 4cyl per their directions. Started the car and I have a 3k rpm redline. Looks like the the tach is reading 1/2 of actual rpm. From what I understand the dub uses a "waste spark" so it only provides a single pulse per cycle and the tach is looking for 2 pulses. Any idea how to fix this situation?

Have you tried setting it to 8 cylinder? cb

yup, it reads even less.

figured it out after a little trial and error.