93 4.3 vortec changed fuel pump and fpr also cleaned up the spider assy and reinstall. Now when I tried to crank it wouldn't turn over so I removed spark plugs and engine turned over. Just wondering how you install spider without causing this 2 happen. Also if poppet valves were stuck open would fuel pump build pressure?

 

Well vapor lock is something else. Vapor lock occurs in the fuel lines themselves, and it's when gas boils in the lines. Now as to why your engine won't turn over without taking spark plugs out....that sounds like a stickey valve to me.

 

You shouldn't be having vapor locking on this truck. Not until it's hot, and most problems that seem like vapor lock are really fuel pump/fuel filter/dirty fuel problems.