Dead

[crsgmc]

I have a 1996 GMC K1500 5.7. I just got home with my truck on the back of a flat bed tow truck. I left home drove about 20 miles. Went into a store, came out and was headed home. Truck had been running perfect up until that time. Started up the on ramp and it totally died. Got it backed of onto the shoulder and tried to restart. It would not start and acted like it wasn't even trying. You can hear the fuel pump prime. I checked for codes and there were no listed codes. I was sure there would be a code a fast as it died. I did try to start it again after the tow truck left and it was the same. I have been rebuilding this truck the last couple of years and a lot of the parts have been replaced:

New crate engine
New injectors, the new non popit ones.
New distrubutor
New wires and coil
New spark plug
New fuel filter
New Battery
New O2 sensors

Any ideas, I am not an expert mechanic, but I have done a lot of work on this truck. Including all of the above. It has never been in for service, I have done everything. Last problem a couple of months ago it would not start and it turned out to be the starter relay was bad. Any help I can get would be great