Wont start on a hot sunnyday

check starter draw when it gets hot it maybe a bad starter.

crankshaft sending unit creates these issues. if check engine light
is activated during these issues

try replacing thermostat

hard starting problems when engine hot could be restricted air filter.restricted clogged fuel injectors.engine could either be diesel or gasoline.if engine dont start and starter wont turn over engine. could have bad battery ground cable or battery positive cable could have broken place when cable get hot crack increases cause less current engine wont have enough power to turn over.

dirty injectors / feul filters check air filter

it wont start because the engine timing usually be off when the engine is hott

I would check the pick up coil in the distributor.

What is the condition of the starter ? Is this an engine hard to turn over problem when hot ? If so, the starter might be grounding out, this happens only when the casing is hot.

check the timing belt

replace the Main relay located under the driver side dash. It gets hot and the pc board warps.