i see.. well, i know that if the actual chip dies (the one that the antrx chip replaces) or if it has been programmed incorectly, the chip is the incorrect speed or something else has happened, then this will stop the fuel pump from running.
what i will do for you, if you are interested, is i have a copy of a stock ecu chip at home which i used for testing purposes, it works 100% fine in my car, i'll send it up to you and you can have it fitted into your ecu and see if that makes a difference, if it does, then you're in luck, if it doesnt work, well then its replacement ecu time.
you'll just have to find a 28pin socket because i have run out of sockets at the moment.
either way i'm more than happy to help out if i can.