Swapped out Guages

Okay , I swapped out guages and the little electrical paper circut board. Did away with the clock and added the tach. My problem is in my fuel guage(as was the reason for doing this) Guage will peg out until its about empty then itll read 1/8th tank. Was hoping it was guage or computer print on back . It did this before the change. Also I removed the clock and added the factory tach out of the donor dash guages, Seems to be getting power cause it sits at 300 then with key on it zeros out, but is inop when car is running , is the somethin i need to hook up to get a factory tach to work? Both circut boards were Identical so i know thats not the problem. Any Ideas would be appriciated.

No didnt add any wire scince printed boards were identical , Figured it was set up from factory. Do i need to add a stand alone wire to the tach and run to the tach side of dist? Thanks

K thanks . any ideas on why fuel guage acts the way it does?

yea it does , was hoping it was guages cause i didnt want to drop 80 bucks on a sending unit lol.