I have the original d15 in my 91 civic with dpfi, now this problem will usually occur when I drive aorund for a 15 to 20 minutes and then stop at a store. When I come back out of the store to leave I'll turn the key and the engine turns but doesnt start. I can keep trying and trying but I usually just try two or three times and let it sit for about three minutes and then the car will start up. Now my spark plug wires are fine as well as my spark plugs and my cap and rotor. the thing is it never happens when the cars been parked for over a half hour. So it must be associated to heat. any Ideas...?????

 

Check out your main relay, it likes to act that way.

 

main relay. do a search. there are tons of how-to's on this.