Jeep Repair: 88 cherokee fuel pump problem, fuel pump, fuel tank

Question
help, replaced pump and sending unit. ran for 40 miles and quit. replaced pump again and did the same thing. jumpered across relay and cannot get power to connector at fuel tank. thanks jhp

Answer
88 cherokee... kind of out of my area of expertise because of it's age but maybe this can help:
http://www.vfaq.com/mods/pump-relay.html

This site caters to a different kind of 4 wheelers (AWD :)  )  but if you can grasp a little bit of electronics and figured out how to jump a relay then a fuel pump re-wire may be in store for you in the near future.

I would think that there is a lack of power or poor grounding that is wiping out fuel pump after fuel pump.  I would recomend seeing if anything in the re-wire may help, even it it's draping wires across seats and such for a couple of test drives just to rule out old and bad wiring that has high resistance.
Doug