1430 No Ink Printing

Hi, Something strange and probably fatal is happening to my 1430. I had a bad nozzle with cyan and yellow that didn’t resolve after a couple of cleanings. So I refilled all cartridges, reset them and other colors started banding. Ended up flushing all jets in head with piezo flush and syringe used carefully, Fluid went through fine. Refilled all cartridges, reset chips, vent plugs out, and now I’m getting absolutely nothing on nozzle checks for any colors. Ran 3 head cleaning, still nothing. Checked exit port on cartridges to be sure spring valves were working and there was ink there. All seemed fine. Flushed head again with fluid and it flowed through, still nothing when printing.
Any ideas? I’m stumped.

Out of desperation I took the yellow syringe and stuck it in the fill hole while plugging the vent hole to pressurize the cartridge (still installed) to see if any ink would go through the head onto a paper towel. It did, so I did the same with all 6 cartridges and their respective syringes, and got a semi-decent nozzle check, Now everything is printing great for 10 prints or so. I guess the cartridges and head needed to be primed, but I never had to do this before. And I don’t think what I did is a healthy way to do it. Do the refill cartridges for the 1430 need to be primed. And if so, is there a link to the proper way to do it? Also, what’s the best way to make sure there’s no air bubbles in the cartridges? Thanks