theres two lines in an a/c. a high pressure side and low pressure side. aka discharge line and suction line. with ANY a/c system in the world whether its a house, refidgerator, whatever. it goes into the suction line. you cant force it in there. it has to be sucked in. and in order for it to be sucked in the compressor needs to run. otherwise it wont take it and otherwise you wouldnt have to have the car running to do it cuz y would u if it just goes in? you can take that cheap hose and puncture the can, but nothing will come out of the other end because it needs to be sucked. the only way something will come out of the hose is if you take the side that punctured the can off.
unless theres a special "pressurized can" i dont know about. theres no way you can force it in there.
