how long should a defender td5 fuel pump run for with ignition on?

does the fuel pump run on a timer or should it cut out when the lines are full and ready to fire?

Hello Ritchie. My Td5 is a year 2k, which might be slightly different to yours. My pump can be heard from when the ignition is turned on and continues to be heard when the engine is running. It was replaced two months ago with a spurious make. The "original" one was the same but less noisy.

yeah mine a 03 so maybe be slighty different, i think my fuel pump is on the way out as sounds weak and struggling to start when cold, thanks