i had to replace the heater core in my civic so i took out the dash and everything so then i replace the heater core hook everything back up put the dask back on start the car let it run for a min or 2 shut finsh up with the dash and now the car wont start (full tank of gas, new wires and plugs)
you missed/disconnected a plug. does it even turn over? or just “click click” from the keyhole but no motor sounds?
car sound like it want to turn over but wont , evrything connected the right way i think
there was someone on here not too long ago with a similar problem, turned out two of the electronic plugs for things were the same plug, and the two got mixed up and the car wouldnt run.
part car out and sell me the ecu really cheap 
yeah def check over all your wiring under the dash. maybe when you put the dash back on, you knocked one of the plugs out…
im not getting any spark any suggestion why