[rickpilgrim]

Once you know you have compression, you have verified spark at #1 tdc, everything is hooked up correctly and all fuses and relays are good try pouring some fuel in the throttle body, putting the hat back on and try it. A guy brought us a 97 S10 w/4.3 vortec, 82K miles, left in the shed for 4 yrs while in the army, came home put in new battery and no start. Came to us, scanner(We have a Snap On Modus bi directional w/lab scope, very expensive) said everything ok so a cup of fuel and it started right up and is running great again. Boneyard guys swear that all these FI motors sit a few yrs maybe 2 in 20 start, the rest need a bit of fuel to go. It should at least pop or fire with this if the problem is fuel related. If it starts and quits----
I don't know if the posative side or the negative side pulses. What I would do next is pull the upper intake off, plug all fuel lines and wiring back into the spider, pull the nozzles out of the lower intake and let them lay on the lower, unhook the coil wire, put on the eye protection and observe the system as someone cranks it over. You should have a nice cone shaped spray out of each nozzle. If none work it's either all the nozzles are plugged(not likely) the spider assembly needs replacement due to a dead electrical side(possible, our S10 did this) or there is a problem in the PCM system.
If it does have a nice spray on all 8 the problem is not there. I wish I could plug the scanner in and watch the data while cranking. Then I would know.
By the way, we have 2 1998 5.7 Vortecs, a 1996 4.3 Vortec and a 1997 7.4 Vortec and ALL will start/run without the MAF/Air cleaner hooked to the throttle body.