My car won't start!!!!
 

My 92 GSR won't start on Hot summer days, but it starts fine at nights.
I have no idea what's wrong with my car.
Please help me!!!

Heat can kill things like the main fuel relay, the fuel pump, and the coil. Start with the basics: Fuel, Spark, and Air. If you aren't getting spark, check the cap, rotor, coil, if you aren't getting fuel, then check/replace the main relay, if that doesn't fix it, check your fuel pump.

As usual, 1stGenCRXer is right on. It sounds like a main relay.

When you turn the key to ON (not START), you should hear the fuel pump kick in. Listen for it at night, when it starts okay, so you'll you'll know what to listen for. Then, listen for it again during the day, when it doesn't start. If you DON'T hear it during the day, it's probably a bad main relay.

early 90s hondas are known to have trouble with their relays in hot weather. open all doors and let it air out and see if it starts.