Weird starting problem/no crank

[AtomicHoe094]

Hey guys, kinda stumped on this..

About a week ago i put an new yellow top optima in and its been great. (2 months ago i put in a highoutput alternator thats been good). Today after coming out of the gym, the truck wouldnt even crank or begin to crank at all. I had a guy try and jump me with no luck. Gauge on dash shows im around 12 to 13v. over 14v with jumper cables on

Checked all my fuses and seemed to be good. Noticed with the key on, my fuel pump is only "half" working and gave me around 4 to 6 psi instead of my 15psi.

Lights/radio all worked. alarm works fine.

Go to turn the key to start it and nothing. oil pressure gauge kind of goes crazy and notta.

Put in a new starter crawling all over the wet concrete and still same thing. No crank, nothing changed.. put the old starter back in, tried another jump with nothing. Tried jumping the starter solenoid, no luck..

Ground on the block to battery is good. cant find the ground on the block to frame, but its been fine for over 7years when ive had the truck..

any ideas?!?! im clueless right now, might have a tow truck come tomorrow morning unless i can get this squared away early enough..

 

[SunlitComet]

so dash will read 13+ volts but fuel pump is maybe getting less? this sounds like a resistance issue inside the power distribution system where it feeds the switched side of power or contact in the ignition switch are at fault. track your voltage form a problem component looking for bad voltage and work your way back until you hit the area where it is good again and you will find the issue. if you think it is a ground issue with the block look around the back of the heads for grounding cables that attach to the frame.