Reason is because when you tried another injector it did not seem to make any difference and that (my thinking) is that you are unloading that piston when you disconnect it. If another injector had resolved it then I would not have stated that. It is easy enough to pull the lower oil pan and take a gander up into the bottom of the #2 cylinder.
Oh yea - make sure the engine is off when you remove the lower pan.

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Jim

today, I had the injectors checked.....they are fine. I did a bunch of "other" work to the car and thought to myself...."do I really want to put the old injectors back in or just diesel purge the ones I replaced mine with?"....well I diesel purged the ones I had in. (don't worry there is a point here)...while waiting for the purge to run through I was working on something else when the knock started getting louder (and lots of white smoke). I thought it strange because the knock has been getting better each time I have driven the car. I looked at the "set up" and realized the intake hose wasn't fully submerged and air was getting into the system. I dunked the hose back into the purge and after a couple of seconds the knocking went away (almost all the way, although I had to strain to hear it). It got me thinking.....when I cracked the metal injector lines I swear I see air bubbles coming out of the lines. And, only after reading several posts did I even know that I had to "crank the primer pump a couple of hundred times" to bleed the system. The most I have even primed was about 5 pumps (I do hear something which I thought was the correct sounding noise).

So, I am wondering.....could I have mistakenly gotten "air" stuck in the pump (could that even happen) or could my OLD STYLE primer pump be letting air into the system even if it doesn't look like its leaking diesel? Or, does this lead me back to a injector pump that is weakened or its timing off?

I do think the knocking is slowly improving and I think I am half way through my 3rd tank of "good diesel" since getting the car with the gas or whatever was in the tank originally (if you remember it had gas or water or indutrial waiste in the tank which made it go only 10mph and blow white smoke).