Been there before as well. Think you did something wrong just to find out it's the parts.! There are only a few brands I personally use and currently trying to get my 2 boys to understand why. And even using the same parts store. I give a shout out to Brad at the Fayetteville Autozone he is the man!
My son is 19 and this was an eye opener. It was also very frustrating! Now he has $260 in 2 bad pumps to return and I'm sure the first thing they will say is "Well they have a lifetime warranty". Prob is this junk only has a lifetime anymore of a few months - if they arent DOA like these two.