MJ runs but only when the key is in the crack position

[88mjsally]

The 89 lwb is back together but only runs when the key is held in the run position. I’ve changed the fuel pump and latch relays, the ignition switch, bypassed the ballast resistor, and changed the tps. Also changed the starter relay which was also wired incorrectly. All new fuses in the fuse block too. So I’m currently stumped as to what the issue is. Any ideas would be much appreciated

[scaleless]

The starter relay has a terminal labeled "F" - this is connected to the fuel pump and bypasses the ballast resistor when cranking.  Sounds to me like there's a corroded connection or bad wire that is getting bypassed when you're cranking.  I'd hook up a fuel pressure tester and check if it builds pressure in the ON position.  Or perhaps just listen to hear if the pump is on at all.  I'd check the fuel pump ground behind the driver side tail lamp, as well.

[88mjsally]

Problem solved! Bad fusible link to the fuel pump. Only 5v was going across that link so I changed it and now it runs great!