Car doesn't want to start in extreme heat

I have had trouble getting my Honda Accord (1990) to start when it gets hot (into the 30’s). It will start when it cools down in the evening. By the time I get it towed for a diagnostic, it starts. Ant comments out there

The main suspect could be a faulty main relay, which is a common problem on these cars. It’s like this one.
http://www.partsamerica.com/productdetail.aspx?MfrCode=SMP&MfrPartNumber=RY186&PartType=598&PTSet=A

Other less likely possibilities could be the ignition switch or the ignitor (part of the secondary ignition system).

I’m assuming here the failure to start problem is that the engine is being physically cranked over by the starter motor but the engine itself will not start.
If you mean the starter motor does not do anything then that could be a faulty ignition switch, bad neutral safety switch (auto trans) or clutch safety switch (manual trans), starter relay, etc.

The PGM-FI relay is under the top of the dash. You can usually get an engine start in a few minuets if you open the car windows and place a cool, wet, cloth on the dash, on the right side of the left-mounted steering wheel.

thanks for the tips. Gives me a staring point.