ive got a compression tester for a gasser, only goes up to 300psi

 

does not go high enough and you have to have an adaptor to Screw into the glow plug holes

 

Ive got an update on the truck, found out i was having a lot of air getting into the fuel system, ive fixed most of the potential spots where i had put in new lines already and just didnt have the hose clamps tight enough, there is a fitting on the back of the fuel rail on the drivers side that has a line going down the bellhousing of the trans, then the 2 other rubber lines on the fuel rails and the hard line that runs back to the front of the motor, that fitting moves quite a bit, but isnt damp or even look like it has leaked anything. Wondering if thatd be a good idea to replace, and if there is anywhere else in the fuel lines between the motor and tanks that may be a potential spot for air to seep in

 

Keep in mind a diesel fuel system is not the same as a gasoline engine system. Gas systems usually are pressurized from the pump inside the tank whereas a diesel usually is vacuum from the supply pump which is NOT in the fuel tank but mounted in between the tank and engine and if there is any place it can suck in air, IT WILL.
To confirm there is no air getting into the fuel lines to the high pressure pump on the engine, a sight glass type fitting is placed in the line just before the hi press pump and it will show bubbles if any air is getting into that line.

 

I have wired in an electric pump to bypass the mechanincal pump on the motor, when i turn the key on the pump will be loud, then quiet down, when i press in on the shrader valve there is air for a little while, then just straight diesel without air coming out, i have bled my injectors 3 times, each time there have been small air pockets in the lines, i only put 5 gallons of diesel in the front tank about 2 months back, i think thats all thats in the tank, so maybe its pulling air from the tank as well, this is my first diesel so this is all new to me. So if its pulling the fuel instead of pushing, im wondering if there is a crack or a small pin hole in the lines going back to the tank and thats causing the pump to pull air right as i turn the key after it sitting. I cannot get the truck to start on ether, or even pop off on it, so i could have bad compression as well, i just have no way of getting it to a shop that has a compression tester