Your lift pump in the stock location is right behind the fuel filter housing. If it works at all you can hear it run or have someone turn the key to the run position and put you finger on the housing and feel it run. If you got nothing at all you have "lost your prime" to the VP44 injection pump which will run without a functioning lift pump, but not well. It cannot pull enough fuel from the tank to run without the lift pump and the pressure head delivered by the lift pump keeps the VP44 cool. You will absolutely need at minimum an OEM lift pump to get your Cummins started. A better solution is a relocation kit to put a DDRP lift pump on the frame rail in front of the fuel tank. An OEM lift pump will cost about $200.00 , the relo kit costs about $100.0 and the DDRP can be had for about $300.00 from Geno's. Now if you only do the OEM pump you will sooner than later probably have to replace the VP44 because the pump may have been wounded by the loss of the lift pump. That rebuilt unit is in the neighborhood of $1,200.00 from many on line vendors. I did all that to my 2002 which had the same fuel system. Diesels are great, but you really need to use them hard to justify the maintenance cost. Good luck.