93 S-10 ECM B Fuse

1993 Chevy S-10 2.8l V6
i recently was the recipient of this vehicle, it did not start. everytime the ignition is switched to the on postion the 15 amp ECM B fuse blows. was able to isolate it to the circuit to the fuel pump relay circuit. when fuel pump relay is removed and the igntion switch to the on position the fuse does not blow.
on the switch side of the relay i have the fuel pump, oil presure sensor, fuel
pump test lead and oil pressure input to ecm. i have gone as far as isolating the fuel pump and oil pressure sensor by disconnecting there connectors and switching the ignition to the on position. fuse still blows. with fuel pmp relay removed and 12v jumper wire to fuel pump vehicle will crank and run. i am running out of idea's an would like some help. thanks

Things to check for.
Try a known good relay.
With a fused jumper on the gray fuel pump wire that is tyed into/with the /oil pressure switch senser feed and feul pump prime connector and pcm fuel pump signal.
See if it blows a 15 amp fuse to start and run fuel pump.
If it will run fuel pump with a 15 -20 amp fuse.
Check how many amps the gray wire circuit to fuel pump is pulling to start and run the fuel pump.
It should not be pulling over 10 amps at the most.
Also find the fuel pump prime connector that is tied into the gray fuel pump relay wire and make sure it is not hooked up to anything or shorted out.
Aso look at back of fuel pump relay block for problems.
Let us know what you find.
Good Luck

Also with the relay pulled check the amp draw on the EMC B fuse circuit.
Something else on the EMC B fuse circuit could be overloading the fuse.
Good luck