u can't add R134 to R12 system

both frigrant can and pressure port use different adaptor, unless u put on a r12-r134 adaptor. since u said u did add some R134, I would say most likely u car is R134 system, make sure of it 1st. also, if u DID add R134 to R12 system, u AC is just gone!! R134 will mess up with lubcant used in R12 system and forming some solid stuff, hence clog whole system.