aftermarket tach
 

I've got this question in the 2nd gen forum and still haven't got an answer, anybody out there really up on 2nd gen/turboII electronic ignition? I've got a '87 TurboII in a car thats not a RX7. I'm using the stock coils ignitors, but have a Haltech E6K. I've got a vintage (1978) VDO tach. I've taken a lead off the trailing coil and get a signal from it (using a multi-meter) that raises with RPMs. I get no reading from the tach. (The tach is getting 12 volts) I have tried all the settings on the cyl dial on the back of the tach (2,4,6,8 cyl)