There's a fitting with a schrader valve down between your vp and the filter. Easiest for a quick check while doing the starter bump. Later you'll be wanting one in the cab so you can monitor it. Google it for the install. Geno's has the fittings. Where is this "new lift pump" located? Can you hear it running? What brand? Battery terminals should be re-done if they're even doubtful. All grounds need to be in good condition, very important. Have you visited Blue Chip Diesel to do the vp hotwire?