91 Honda Accord, when it's hot out my car won't start

If I leave my car parked in the sun for 10-15 minutes it won’t start. One mechanic said to try and pound on the dashboard (that doesn’t work.) I’ve got a new excellent battery but even so have gotten a jump a couple of times and the car started (even though it was turning over okay and all the buzzers and bells worked.) I just tried the jump trick again though and it didn’t work and I’m stuck. Anybody got any suggestions???

I remember some discussions from time to time here about a problem with Hondas about that age where a relay under the dashboard stops working when it gets too hot. Some searching here and on Google ought to turn up some details.

I think it is the fuel pump relay you are talking about. To see if that is the case spray some starter fluid into the intake. If the engine fires up then it is a fuel delivery issue. If not, check the ignition system for a problem.

This is a long known problem with Honda.The circumstances fit perfectly to a problem with the PGM-FI relay under the dash, where it gets really hot in the sun.
The PGM-FI relay can, sometimes, be jarred into working again when the top of the dash (to the left of the steering wheel) is pounded upon. Another temporary fix is to open the car doors/windows, and let the inside of the car cool. After about 15 minuets, turn the key and away you go! (until, the next time).
The PGM-FI relay (aka: “main relay”) is $70 retail, and (about) $110 from a repair shop. It takes about 1/2 hour to change.

For the mechanically inclined, and on your own vehicle, and as a temporary “proof of concept”, you can, temporarily, bypass the PGM-FI On 1991-93 Honda Accords. Remove the PGM-FI relay, and jumper the wiring harness that goes to the PGM-FI relay. Jumper female terminal 5 to both female terminals 7 and 3. Terminal 5 is 12 volts from the ignition switch. Terminal 7 goes to the fuel pump, and terminal 3 goes to the engine computer (ECU).