Brake Pressure Problems

[chuckseabo]

Looking for help. I have been searching the forums looking for help with the issue i am having with my car however I couldnt quite get the answer for my problem. I am sorry if this seems like a redundant post. I had my engine replaced and got the car back at the beginning of this week. When I left the garage there was some brake pressure however by the time I got the car to the house there was no pressure. When the car was off there was no pressure so we replaced the master brake cylinder. Now there is pressure when the car is off however no pressure when the car is turned on. We bleed the brakes in the sequence instructed for car. All the air is out of the system and still there is no pressure when the car is on. We disconnected battery for 15 minutes and hooked it back up. There reason for this was that there was a post i was reading where the abs may lock shut and to reset them was to do this. Either way there still was no pressure when the car was turned on. Again we bled the brake system and still no pressure when the car is turned on. There are no lights appearing when the car is turned on. We don't have the tool for the abs sensor. In the end here I am no sure if there is something I am missing. Does the abs system have to be bled even if all the brakes have been bled? If anyone has any ideas please help. Thanks. The car is a 2001 alero v6 all stock.