First off, there are no poppet valves on these injectors. There are spool valves and yes there are relief ports that weep oil when the spools are moved and when the intensifier piston cycles. There have been injectors that have failed by a number of sellers over the years, but the rate of unexpected failure has dropped dramatically with the installation of new or rebuilt spool valve assemblies. Almost all of the injector issues seen were caused by spool stiction, not spool failures.
Second point. I don't work for any injector seller, but I did take the time to understand how the injectors work and what are the problem areas that cause injectors to fail. I did make 4 sets of injectors that have all run perfectly over the past 4 years - I did just recently have a nozzle failure on one of them. There have been many cases of "bad injectors" that were a direct result of installation error, including from mechanics that were not closely following the correct installation procedure. If you would do a search for burned, damaged or missing O-rings, missing copper seals, loose injectors, combustion gas in the fuel rail; all of these are primarily installation errors.
Now on to your apparent problem. As the injector cycles, oil will come out of the weep holes on the top of the injector. You typically would never see it, except as run-off as the rail covers the spool. Oil may also be coming from the rail nipple or even from the injector nipple seal - not good. FWIW, when you apply air to the rail, you will get some air moving through the seals, but not much and it typically happens once the oil has been displaced by air. So, I don't know how you diagnosed a bad injector, except for perhaps applying air to the top of the injector and watching oil come out of the weep holes or perhaps out of the side where the intensifier piston relief hole is. If the spool valve was not in the closed position with air applied, you would see more oil or air than expected. How did you test them? Did you apply an electrical impulse while applying fluid pressure? Now, it is possible that you have loose (worn out) spools? Of course it is, but 6 out of 8 is way over the top, even for a bad injector modifier/rebuilder!
This was an old thread reactivated. A lot of magic surrounding injector modification has since been demystified. Most of the 6.0 problems (injectors included) have been identified with the fixes readily available to those that choose to find them. There used to be 100s of postings a day, now not so much as there are less 6.0 owners and less owners with problems.
So back to my initial questions in the previous post.