i would guess wires before relay...once a relay shorts out it's pretty much done for. however they are cheap so i would replace that first...assuming your wires have no shorts in them...also go in there and check the wire at the fuel pump...you will have to do this when it isn't working....if you can be so lucky, if power is going in before the relay and not going to to pump it's the relay if power is going to the pump and no pump action then you need to check the pump and make sure all wire connections are firm if still no luck replace it. also your ecu will remember if you turned the ignition on and then off (fuel is sent to engine) and will not send it again the next time you start up. you might have some trouble with that, i'm not sure how long the delay is but that might be other possibilities