It sound like you have a leak of filament from between the end of the Bowden tube and the nozzle. Make sure the end of the Bowden tube is really cut square and pushed down hard onto the back of the nozzle. Both of these processes are harder than they sound, get a raelly square cut with knife is very difficult and even a small error can cause leak in the same way getting the tube seated well needs a quite large amount of force to be sure.