im helping one of my friends put a motor in his truck. its a 4.8 in a 02 sierra. we got it in last night and hooked everything back up, when we tried to fire it up it wouldnt crank. after turning the motor over a few times i pulled a plug and it was still dry, i turned the motor over to see if that plug was firing and it wasnt. so there is no fuel or spark. what is the problem?

 

i done some more checking yesterday, the fuel injectors and the coil packs are getting electricity but the injectors arent spraying and the plugs arent firing. ive checked all the grounds and they all seem to be tight, anybody got any ideas?