1999 Chevy S-10 No Injection Firing. No Start

143000 mile 1999 Chevy S10 4X4 Auto.
Father-in-Law's truck. So initial problem, and events were relayed to me.
Apparently a slight electrical whine became audible through the speaker system after hitting a "big" pothole. The truck continued about a hundred yards before dying and not restarting.
To make a long story short. All electrical systems have been checked for resistance, cam and crank sensors replaced (checked and rechecked). Pass-Lock checks out as OK. Fuel pump replaced and all wiring checked. Computer system checked.
We have fuel at the injector housing and are receiving a signal through the positive side from the computer, but apparently aren't triggering on the negative side. The injectors do not fire during cranking. Negative side has been checked from injector housing back to computer pins for resistance. OK. The injectors were replaced with a known good unit. Still no trigger signal. There IS fuel pressure to the unit. There IS fire from ignition system. However, there is a consistent "low ignition voltage" trouble-code (P0134.I think. Truck's not in my possession.).
Haven't checked against new computer yet. They have checked against a known good computer from same model truck. It's my understanding that it would need to be "flashed". What's the procedure on this?And why no trigger signal from the current unit?
Any suggestions would be very helpful, as the truck has been down for quite a while.
Thanks.