Hello, my 91 civic hatchback dx suddenly quit while driving--as if it ran out of fuel, and I couldn't get her going again. The usual dash lights work when key turned to position 2 and the fuel pump primes for 2 seconds. The check engine light does not come on. The starter turns the motor over easily but it doesn't even try to catch. There is no fuel smell from the exhaust after turning the motor over many times. I checked the timing belt by seeing the valvetrain move as I rolled it forward in gear. The ECU only blinks once when key turned to position 2. Is it possible the main relay is gone even though the fuel pump primes and there is no ECU code? Can a fuel filter suddenly kill the motor driving at about 60 km/hr? The entire distributor is only 2 years old and the car has 186k. The car always did need to be turned over a few times before it would start--unless it was already warmed up. Also, if I didn't turn the key from position 2 to 3 smoothly--after waiting the 2 seconds to prime, I would hear a relay chatter. Any help would be much appreciated. Thank You

Check for a bad MAP sensor, which affects timing and fuel/air mixture. If it fails, you won't get spark. Replacements are expensive, so shop around. A failing MAP sensor often manifests itself in the relay chatter you describe. Apparently, the MAP sensors on many of these older Civics are starting to fail.

Check if you're getting a spark. If not, you might have a shot igniter unit.

Also, you might have problems with your ignition switch.

Are you actually getting fuel pressure, or are you just hearing the pump come on?

I had this problem with my 1991 civic and it was a rotor switch and spark plugs. I was told by my trusted mechanic, although they replaced both I honestly think it was the rotor switch that was bad because I replaced the spark plugs and wires only months earlier.. I don't this is a "fuel" related problem but it could be possible. Common reasons would be rotor switch, spark plugs and wires, battery, alternator, battery cables, ignition, or more serious problems would be fuel pump or fuel injection related although I think you are definitely looking in the wrong place here.