2001 jimmy 4x4 4.3 crank, no start

Preface this with: No history on this truck. Bought Used, as is where is.

2001 GMC Jimmy 4x4 4.3L 212K miles

Started kinda rough but the first 60 miles was fine, drove good, idled well, good acceleration then headed home and just quit. Turns over fast and wants to run and if you hold you foot in the throttle, it will, at about 1800 rpm but makes a fuss...sounds like its missing, engine rocking on the mounts a fair bit.

Changed the usual culprits, and they all needed it, badly. Distributor cap, rotor button, coil. No luck. Swapped a known good coil wire on advice and still no change.

Next leap of faith and changed the fuel pump. Got it all buttoned up and turned the key...no prime. No nothing. But the fuel gauge works, so I know it has power. Had to change the wiring harness, fairly straightforward with no problems. Gray to gray, black to black, purple to purple and striped to striped as per instruction with crimp connectors and a good wrapping of e-tape. The sock was black as smut and had the paint markings of being re-built, so this was a large chunk of change and time, but I don't think it was not unneeded.

So, no fuel pump. Must be the relay. Pop the box and stare for about 5 minutes at a gym clip..yes, paper clip jumper, from the horn fuse ( now a 25 amp) to the fuel pump relay. Discard and buy a new relay. VERY loose in the socket so bent the prongs outwards just a tad to set it well. Still nothing. No fire to the fuel pump.

No pressure at the rail, just a few trivial drops. No codes.

So, I ask with hat in hand...any suggestions?

Pull the Fuel Pump Relay, and apply 12V to where pin 87 of the Fuel Pump Relay goes into the fuse panel (if it were plugged back in). This should power up the fuel pump. If the pump turns on and the truck starts, either the relay you just installed is bad, or it's very possible the wiring to the fuse block is bad (or the pins them selves aren't making contact with the relay). If the pump doesn't power up, you'll have to pull the plugin off the pump and verify power and ground at the pump before going any further, and troubleshoot the wiring further.

Note: There should also be a separate Fuel Pump Prime connector, in the engine bay (a one pin female connector, which will do the same thing if you apply 12V to it. I can't remember it's location off hand.

Okay. Tried the hot jump from 87. No fire, however...the tag lights came on?! This is looking more and more like the previous owner had fuel pump relay problems, which would explain the very very worn sockets in the fuse block, and tried to pull an ignition hot from somewhere at the back of the vehicle. Will try to chase that down this weekend.