I have a 93SE 5spd and tried connecting my new aftermarket tach but I hardly get any signal. I have it connected I get lights from the thing and the needle moves but not the way it should. It stays between 0 and 1 throughout the entire RPM range, I can rev the crap out of the engine and it will move from zero to half way to one.

I ran the signal from the OEM tach and then straight from the coil and got the same result. I checked the ground and that was alright. I even tried another Tach and still didn't work. Someone said I should run it from the ECU directly, will that work?

Anyone have any idea what the problem could be? Any help will be appreciated!!