It was blocked somewhere in the middle of the tube. I could not blow air through the end starting at the return line and could not blow air through the 1st 2 rubber lines closest to the return line.So out of curiosity, was the hard line plugged near the Banjo fitting and no fuel is passing to the metering pumps? Or are you saying the tube is clogged near the far end and the fuel can not reach the bypass that goes up to the injector returns? If you are only talking about the bypass to the injectors, I've seen several that were blocked off, but not with junk, they appeared to be blocked from the manufacturing process, possibly with brazing or something as I had to drill a tiny hole through the end. Not sure if it is supposed to be sealed off by design or not.