Have just installed A TT Vapour on my TE 250, but the Tach says Im doing 10,000 rpms at idle?? I have hooked the power for RPM to plug just behind coil so it is after both spark plug lead & coil! The Earth I ran a common ground through old speedo ground! I'm wondering if I should have gone solo for tach? Also values for PPR (pulse per revolution) I am thinking it is 1! Can anyone help please? Grant Starr