The car is a '92 Civic Si hatchback, completely stock.

Sometimes when the engine is still warm and I go to start the car, it fires up, but immediately stalls. It only does this intermittently when the engine is warm, not when cold. Another clue I have is when I turn the key to the "ON" position, sometimes I won't hear the fuel pump priming, and those are the times when the car will stall after I crank it.

Is this a relay problem, fuel pump problem, or both? Which relays are involved getting the fuel pump going?

 

Did you check your main relay?

 

Main relay controls signal to the fuel injection circuit and fuel pump itself, the symptoms of a failing main relay are exactly what you have described..

 

plus i have seen it documented that hte main relay can get a bit cantankerous when warm...

some reports suggest that your can open it up and check for loose solder joints...

or you can replace.

to know for sure, locate the main relay and have someone turn the key to on nad it should;

click - 2 second pause - click

HTH,

t..