1991 Honda Civic no start situation

I have a 1991 honda civic hb dx 1.5L which has intermittent starting problems. The car always starts when it is cold and runs perfectly getting 30mpg around town and 40mpg+ on the road. When the car is warm and I turn it off for a short time, 5-10 minutes, sometimes it will not start. The starter turns normally but it will not start. If I let it sit for a few
minutes, it starts like everything is fine and continues to run beautifully.

when I turn the key to the ll position, the cel comes on for a short time and then turns off and I can hear the main relay click. Is it possible that the ecm is not energizing the fuel pump for the two seconds to start the car? I have a hard time hearing the fuel pump in the start or no-start situation. How do I determine if it is the ecm or the main relay that is not sending the correct signal to the second relay, injectors or the fuel pump?

so far, it has always eventually started and I don't think the temp has changed much between the start and no-start periods. The fact that it always runs well when it starts leads me to think it is not the main relay. I have not changed the fuel filter in 5 years so I will start there but if it were the
filter, why only problems when it is hot? There is a little ground wire at the bottom of the distributor which appears a bit whipped and I wonder if a bad contact there might cause arcing and overheating but why wouldn't it cause the car to cut out in normal use? How about the coil, igniter or fuel pump
sock as possible causes? Any direction would be greatly appreciated.
thank you, gerry connery
Email: gconnery@aol. Com