Faulty wiring at one of the connector plugs?
Is the fuel pump earthed through the oil pressure switch on these cars?
Make sure the relays are identical to any you replace. I changed (cos I lost it ) a (bosch) fuel pump relay on a previous car with one that was marked identically but the car wouldn't run with it fitted. It wasn't until months later when I found the origional relay and re-fitted it, the car fired up straight away

Have you checked fuel delivery? It could be priming the system but pump not running after that, hence abot 2secs of running.