BMW Repair: 84 bmw 528e ignition problem, bmw 528e, ground connections

Question
ive own this car 15yrs i started getting intermittently starting problems so ive replaced starter still same problem but worst must presskey hard to start now , now it starts fine when its cool outside like first thing in morning or late in evening but if cars been sitting in heat all day on hot day it wont start at all unless i start it from starter myself please help ive just brought new ignition switch and tuimbler and keys but havnt installed yet   please help me Mr Don

Answer
It is possible that the electrical part of the ignition switch is bad.The mechanical part is just that mechanical.It could be worn out(doubtful),you would see when removing the tumbler from the column.Check all your electrical connections, ground connections,and the wires(bumpy looking although the casing is complete)