Quadstar is not all the hype you think he is.... 5288 was superseded by the 5521 which is the basic standard for quite some years. If it don't run right get rid of it. But a good 5288 will run as good as a 5521. No reputable dealer would build one to 5288 specs as newer improved parts are in the 5521.
If you find a non OEM crank sensor that works great let us know. The 6.5 is notorious for causing all kinds of problems with the off brand sensors. Evidently the 6.5 ECM has trouble recognizing the signal and creates havoc No one here has used an oscilloscope to verify what is going on with these sensors. I suspect some evil conspiracy in the part but I don't have the time to investigate the problem. I may have been the one here that discovered this issue years ago...
You need to junk the "marine" injectors and the pump as you well know now they are inferior products. One thing that will pop a return line off is an injector that has one of the two holes plugged up. In all the cases I have seen this is on Chineeseum Injectors. The holes where not drilled all the way through. Since the fuel has to return out these holes pressure can build up and then the hose blows off. Marine injectors are really bad performers. Very poor atomization. New Delphi or Bosch will out perform them. Almost ALL marine injectors are China made because they are cheap.
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