aftermarket tach problem

[DOHC VTEC]

i just came across a autometer 5 inch tach with shift light and hooked it up im my car i have the rpm wire run to the dist wire but ireads about a grand lower than my factory tach and there is another wire that i hooked it to and it makes it run about 4 grand faster than my factory one and the backlight doesent work and the tach can still be set with the key off. someone please help im comfused

 

[CivicMafia]

You may have to unhook your stock one... I had a problem with my tac jumping around come to find out the connection was loose...