try pulling the wiring connector off the ecm. check for continuity between the battery ground cable clamp(since the neg battery cable will have been disconnected, please, so no burny-outy ecm like me) and pin numbers 20, 40, and 60 on the connector. it may be that the ground(s) for the ecm became disconnected or severed.
iirc, when i was trying to get my truck going the fuel pump relay wouldn't activate till the key was inbetween the RUN and START position(the fuel pumps would activate for the normal 2 or so seconds if i slowly turned the key to START and as i slowly let the key back to run). i read something in these forums at that time about circuits "scavanging" a ground and i think thats what happened at that point of rotation of my ignition switch. maybe i missunderstood the posters meaning but after i finally found that pin numbers 20, 40, and 60 on my connector had no continuity to the battery ground i snipped all three and ran a thicker wire joining all to the neg cable clamp. first click of key to run after that had pumps priming. turn a little more forward and truck started right up.
so, yeah............ told myself i wouldn't do the two-finger blah, blah, blah, but i did. got some practice in on the run-ons, too. hah!
to digest the above:
the ecm controls engine functions such as fuel pump relay and injector pulses by providing a ground for those ciruits. if the ecm has no access to ground via pin numbers 20, 40, and/or 60(and pin 16 is listed as ign-gnd on my printout of "TRUCK COMPUTER PIN OUTS" from fordfuelinjection.com) then those systems will mal- or not function. [/blah]
p.s. if you knew above info already or if i seem to be over explaining, there was no intent to insult your or anyones intelligence. sometimes i start posting with no exit strategy