I bought a 1996 Civic DX about a year ago. I have had no major problems but one thing seems to occur in the summer or when it is sunny. My car usually starts fine in the mornings. However when it is hot/sunny it does not like to start right away. A friend told me it may be an issue with the main relay because he can't always hear it click when it turn the key. If I turn the key and don't hear the click I know it is not going to start. It never has. Also, and this only happened a couple of times when it was cool/winter, if I stop and turn the car off sometimes it will not start right away. Again, I don't hear the click. Usually happens when I stop for gas. Any advice is much appreciated.

 

I had a similar problem, the car sometimes would not start if the engine was warm or if it was raining. My main relay looked fine visually but after i reflowed the solder on the relay all my problems went away. Just remelt the solder and see if it helps, its known to crack over time. The most it can cost you is a 2$ Harbor freight soldering iron.

 

Acura Honda Main Relay Solution

could also be bad ect sensor. test on the car to avoid coolant system bleeding headaches
if it's still good (ask me how i know lol).

How to Test a Coolant Temperature Sensor | DoItYourself.com

 

Definitely the main relay solder joint problem. Always seems to happen when you stop for gas or when the sun hits the driver's side fender.
If you're in So Cal, I'll fix it for you for free. It's totally easy. As an aside, until you get it fixed, just know that getting cool air under the left side of the dash, just above the kick panel, will help your car start sooner.