Will not start unless primed?

Before I read your last post I checked the fuel pressure. This fuel rail doesn't have a banjo bolt to connect the gage so I used a T adapter that came with the gage. I connected one end to the fuel pressure gage and the other to the hose from the fuel filter. I connected the gage to the T. I had someone turn the key on several times to let the pump prime, but the gage registered 0. We cranked the engine and the gage read 45 lbs. For a few seconds then abruptly dropped to 15 Lbs. So it seems that the fuel pump is not working since I have a new fuel filter. Also, I noticed that the fuel gage shows almost empty when I have over one half tank. I checked all the fuses and found the one marked CIGAR was burned out. I replaced the fuse, but it didn't afect the fuel gage reading. I asume my next step is to work on the fuel pump and check the pressure again. I will deal with the compression test later. Your opinion?

I checked compression and thesew are the results:
#1 121 PSI
#2 120 PSI
#3 119 PSI
#4 122 PSI

I installed a new fuel pump and these are the results:
No start
I cannot hear the fuel pump run when priming
Fuel pressure 0
Tank has 3/4 of fuel
Fuel gage now doesn't move from empty with key on.
New relay checks OK
I cannot find a fuel pump fuse in the fuse boxes or in the schematics. Unless it has a different name. Is there one?

Next:
I will resinstall new pump and check connections. Also check power with meter and key on and resistance in floater.

Info: The problem started 4 years ago with high vibration. I changed all motor mounts and didn't help much. I took it to Pep Boys. 2 mechanics who worked on it said they couldn't fix it and after charging me $350 they said to take it to the dealiership. I decided to do it myself and so here I am at age 81 and retired corporate executive. I am in Phoenix and have been working in my garage with temps up to 112 degrees inside.

Sorry for the delay: After I ran a wire from the relay to the pump positive the pump works. How do I test the power and the negative cables from pump to relay?
The new ECM shows two codes: 1. P0340 Position sensor A circuit Bank 1 or single sensor. 2. P0102 Mass air volume air flow A circuit low?

I installed a new Camshaft position sensor, but I got no power. How do I trace the cables from the sensor to the ECM?

You mentioned checking the grounds, but I can't find a chart showing the grounds. I hope you guys can help me.