There are many reasons your Instant Pot is steaming when sealed and not coming to full pressure: 1) There is not enough liquid in the pot. Make sure there is at least 1 cup (8 ounces) of liquid. 2) The silicone ring is not secured. Double check this is in the correct position. 3) The pressure release valve is is in the venting position. Turn the knob to the sealing position.