95 cavalier not firing

last summer my 95 cavalier spun a bearing, it would start but it knocked. i pulled the motor and put in a new crank,bearings,timming kit,oil pump and screen and a new water pump. i put the motor back in the car and now it wont fire. the fuel pump is running but im simply not getting spark. i had the coil packs tested and the ecm and they were both good. i checked for any loose connections but cant find anything. this thing is driving me crazy