electrical problem

acompton

I bought a 02 jeep liberty renegade for my daughter and i had to replace the valves and springs. I put the engine back in and it was running. But now when i go to start it nothing happens. When I turn the key in the ignition I get power to everything it just wont turn over. I read to jump jump the starter relay and when I do that it will start. It just wont start by the ignition. I took it to the dealership and they said it was an electrical problem. I would love some pointers on this. Problem 2 is when I drive the jeep I have no power when I go to pass someone it shifts just fine. Just wont kick down when I floor it. Im getting a code that says no communication from tcm to pcm. Any input would be greatly appreciated