I recently bought new Teleflex Lido gauges.  I got the Tach and oil pressure to working, but I could not get the temp to read correctly.  I checked my wiring which is all new.  The Sender is a Sierra part, could that be the problem.  I wonder if the alumium Intake manifold is not allowing the Sierra Sending unit to ground.  Does anyone know if you have to have a Teleflex sending unit for the water temp? Thank you for your help.