Fuel and temp gauges maxing out??

My fuel and temp gauges are maxing out every time I turn on the ignition. I put new gauge faces on and thought I just put them back on in the wrong spots or something but even when the car is on and I put them all the way down with my finger, they just go all the way back up. I cant tell if my car is overheating or not because there is steam or something coming from uneder the hood but it could just be from oil on the header and stuff (I just swapped engines) Why are they doing this?