Won't start. Ideas needed-Please take a look

[restoguy]

I have searched until my eyes burned and didn't find anyone with the same symptoms I have, so here goes.
First a little back ground.
I had a fuel leak around the filter housing. It would cause the fuel lines to pick up air and lose pressure. In order to get it to start without burning up the starter and batteries I would have to jump the lift pump relay before cranking the engine. This worked fine for the last couple weeks until I had time to fix it(I don't drive it much lately). So today I pulled the fuel filter housing out of the rig and cleaned it up. I replace the O-rings on the heater and water sensor and put the filter back in. I jumped the LP and bled the air out of the filter housing. I knew that the line between the filter and IP probably had some air in it, but figured what the heck, it would work it's way out. I've had this pickup('94 K2500 w/4L80E) for 5 years now and I've replaced the fuel filter numerous times.(Not to mention the whole engine 3 times and an injection pump once!) So I've 'been down this road' so to speak. I cranked the engine and it fired right up, ran for about 5-10 seconds and then died. This was to be expected. I cranked and cranked again and got nothing. I figured that I had air locked the pump so I loosened an injector line to bleed the pump. I cranked again and it tried to start then died. Assuming that I had bled enough of the air out I closed the line and tried to start the truck. Again, it would not start, nor even try to. I opened three lines this time and when I cranked it I got no fuel or air at the injectors. I have checked to see that I have fuel being pressure fed to the IP, the fuel shut-off solenoid is operating correctly, and I have some fuel flowing through the retrun. I have checked numerous times to verify that there is no air at the filter housing. With an injector line completely removed from the injector I don't get so much as a drip of fuel when the engine is cranked over. I know, you're thinking "PMD". Well, I have two on the truck. One mounted on a cooler and one on the pump. Both were known to be good with in the last week. The truck drove into the shop on one PMD and the other was just used a week or so ago when the truck stalled. The stall was later found to be air in the line and not PMD related. I have tried both PMD's and neither produces any better result. The pump is not metering fuel for some reason. I can discount the PMD, but can not find the problem. Anybody have any thoughts?

P.S. I have cranked the engine enough in my attempts to fix this problem to be equivelent to about 6000 miles of driving! So I do not believe that there is any air in the system causing this problem. I believe it's a pump problem, but I don't know where to start short of pulling the pump. Thanks for your help, ahead of time!