'87 S-10 ECM fuse blows instantly??

I have a 1987 S-10 2.8.
Yesterday it shut off while running and will not re-start. I am unable to pull trouble codes due to ECM B fuse is blown. When I replace the fuse it instantly blows (with key off). Vehicle will turn over and will run while throttle body is primed. I understand the ECM B fuse powers the fuel pump.
Any ideas on what is causing the short? Fuel pump, fuel pump relay - or a problem with the ECM its-self?
Thanks in advance,

Vtwin

Probably a bare power wire touching some metal somewhere. Trace the wires and you should find it easily.

I traced out the engine compartment & fuel pump wiring examining it for damage. I did not find any damage. However when I re-inserted an ECM B fuse, it did not blow. Vehicle starts great - no codes present. I now need to retrace out the wiring in more detail to find the short.
Thanks for the advice.

I had the same problem with my 87 S10 with 2.8 in it and took me for ever to find it, but what happened to mine was the cab mounts were bad and the cab started to sink and when this happened it pinched wires between the cab and motor/transmission. Finally figuring this out it was about 4 or 5 wires that ran down the back of the motor and few of them were grounding out on the cab. Hope this helps, i'm not sure what the wires were for.