1993 Jaguar XJ40 No Start

My car ran fine but one day it did not start. I had a mechanic look at it and he said the Fuel pump did not start. I put in a new Bosch fuel pump and it ran fine for 3 weeks and than it stalled while driving. I listened for the fuel pump and the fuel pump had stopped running again. I changed the relay located in the trunk and pulled out the gas tank again. I removed the fuel pump and tested the pump outside of the car and it worked fine. Put everything back and the car started. I let it run for 10 min shut it down and started it again, started first crank. I let it run but after 15 minutes it died. Checked the fuel pump and it had stopped running. I had a 2nd person crank the car and I could hear the pump go off and on during the crank but no priming at the on position. The car sounds like it wants to start but no go. Is there another relay that tells the fuel pump to turn on and stay on?