Dead hole. What’s the next step

Good that you figured it out. And like RRR said you were looking for a leak, the leak down tester tells you how much of a leak, you didn't need to know that, you just needed to know "yeah its leaking when it shouldn't be" Its like a "go no go" test. Also like PRH says you take not of any "visual" indicators of what is "broke" . remember think "inexpensive and easy" things first... or KISS method. we all ran out and bought parts when we were starting out, but it gets expensive. have you ever bought a starter only to find out its the battery or a bad cable? Also dont be afraid to tear that thing down. Its fun and you'll learn something :)