fuel problems

My sons 1988 2500 Sierra will not start after you shut it off for about 30 minutes. We have replaced the fuel pump.When we did we found a hot wire running from the 3 prong plug(cab part) of the sending unit to the fuse box. This keeps the pump running all the time the truck is running and I think the the pump gets hot. Does anyone know how to fix this problem. The truck will not get gas until it cools off.

Welcome to AF. Your query is unclear, If the pump runs all the time how does that affect the not starting issue. Pull the relay and see if the pump stops, How do you know the pump gets hot, it is in the gas tank.

Was the fuel pump an aftermarket fuel pump?The aftermarket fuel pumps are junk and most will not cover one under warranty.Carter and Airtex are junk,they are both to stay away from.Went through that,my cousin's Oldsmobile Alero.Put three aftermarket fuel pumps in and they went bad.The fourth one was from the dealer and put inone of them in.The car has not come back after putting in the AC Delco pump in.

If I remember right you should not hear the pump running continously. Only after the truck gets to running temp will it not start again until cool. I'm not sure how to check for a vapor lock or if it is something with that jumped wire. Yes the pump is in the tank

GM fuel pumps have a big problem with the factory wiring harness. The connector pins in the harness wear out over time (often the harness is bad and the fuel pump is still good) and should be replaced. I have no idea why someone would run a wire straight to the fuse box unless there was damage in the factory wiring.

I work in the aftermarket parts industry and carter and airtex pumps are like playing the lottery, go for delphi if they are available.