Sounds like maybe the tach signal is loaded giving a slow risetime and/or falltime. Did it ever work?
Dakota Digital sells a tach interface controller that will drive most tachs. SGI-8, it is a little pricey but I used one with my repop tach and it worked great.
Don
Hey Don. Tach worked perfect last year. It only has about 300 miles on it.
__________________
69 SS396 Camaro Coupe, 4link, 12bolt posi, Speedtech LCA and UCA's, Hotchkis 2" drop springs and sway bar, Ridetech triple remote resevoir coilovers, Bilsteins, Wilwood 6 piston front/4 piston rear, Magnaflow stainless exhaust, Lemons Headers, Comp rollers/p-rods/cam, Fikse 18x8.5 and 18x10
Brian Hobaugh SCCA National Tour June 2014
First Hemi 'Cuda Convertible Ever Built
Short clips: Goodguys Pleasanton autocross and pit videos
Threaded Mode