ask your fully qualified mechanic and your uncle to help out your mate
about your 4ac..god knows whats wrong with it..you haven't provided any details of what you guys have tried or what not..lol and seriously if a fully qualified mechanic doesn't know whats wrong im pretty sure no one over the internet will..
AE86 is your dream car...time to put some money into it to get it working then i think
buy 4age, install, drive off