Fuel pump relay location

Tap on your gas tank and see if the humming starts. I had to do this to trip the pump. Might need a new pump soon.

You may also want to try to find a disconnected ground wire on the left side of the engine block. Had that problem before. Left side when your facing the engine, just past and a bit below the distributor.

Engine Performance problem
1989 Jeep Cherokee 6 cyl Four Wheel Drive 100000 miles

Hi, Sometimes my Jeep wont start when the engine is warm, but I can get going if I give it a shot of starting fluid.
Sometimes when it is cold there is no spark and again wont start. Then if I let it sit for a couple days it fires right up like it should. I have replaced the fuel pump and filter and the fuel pump relay on the fender Any ideas?

1987-1990 4.0 L AMC 242 I6, 177 hp (132 kW) with Renix fuel injection system
If this is the engine you have check crank position sensor jiggle the wires and or replace