1988 7.3L IDI won't start no air leaks

hey so I bought a 1988 7.3 idi a couple months ago and it has 134,000 original miles and it ran good until it started having air leaks, so I did the injector orings, caps hoses, and that seemed to help along with changing the fuel filter to the full canister instead of the one you screw the bottom onto and it has an electric fuel pump so I can check after it sits for a while if there is air in it and most of the time there is not so I still have a small leak somewhwere, anyways when I don't bleed the air out through the shrader valve on top of the filter housing, and try to bleed it out by cracking the injectors and cranking it im getting little to no fuel when doing that after cranking numberous times with the throttle open, am I not doing something right? or do I need a new IP? I understrand the don't like to go above 100,000 miles but I thought maybe it would be a bit more noticeable that I needed to change it, any help would be appreciated thanks!