04 Rendezvous full brake pedal when SUV is off

Changed the brakes and front calipers on our 04 Rendezvous. Filled the calipers before connecting the brake lines. Bled the brakes with an assistant and with a hand vacuum bleeder. I can pump the brake to a full pedal with of compression with the engine off. When I start the SUV the pedal goes to the floor. I bled the rear first then the front, I have bled them several times at each wheel with no luck and the same results. Suggestions? :banghead: