I have a 2008 chevy equinox and just replaced the motor and went and powerwashed the engine and now it wont start what is this

You most likely got water in some of the sensors and it won't start until the water has evaporated. The vehicle's CPU doesn't like it when the wire chassis' get wet and it may lift the ground to the starter because it recognizes there is liquid present in a vital area and it doesn't want to blow your fuses, which I hope you have already checked. EFI motors don't like getting wet.
Let it dry out.

OK, 1st mistake....NEVER POWER WASH A ENGINE!!!!, you may steam clean , but never use a power washer. What you have done to it now can be any number of things from breaking wires for the starter to having water in the electrical, Alternator or other places. At this point, try taking a hair dryer to all of the electrical connections under the hood or put a torpedo heater near the front end and hopefully the heat will dry out the affected connection. Be very careful now...make sure you check you oil for water, DO NOT START the car before you make sure water didn't get in the oil.