I just installed boost, oil pressure, and egt last night, but i haven't hook up the egt senser and oil pressure senser yet. but it seems strange that when i turn on the car, the oil pressure would stay at 0, but egt would stay all the way up at 2200f. is it becoz of a bad ground?

It's because your gauges are looking for the sensor values. I'd disconnect the power to these two gauges until you connect the sensors. Just to be on the safe side.