Truck Repair: T444E failes cyl. contribution on 2,4,6,8, 444e, pump fuel

Question
I'm working on a 1997 Int.3800 bus with a T444E it has lost power with excessive blue/white smoke cylinders 2,4,6,& 8 fail cyl. contribution test. we have replaced the injectors, under cover harnesses,& cover gaskets . we have also replaced the high psi pump,IPR,ICP,CMP,EOT,tamdem fuel pump,fuel PSI regulator,EBP sensor& solinod. We have replaced the ECM,Injector driver modual,VPM & wiring harnesses from a known good source. We have also cleaned the EBP sensor tube. Hopefully you can help us we have been 3 weeks doing every thing that has been suggested to us but nothing we have done has worked.

Answer
WOW, you have tied up some money and time in that engine!  You covered all the normal items.  Some other things I can think of is:  Double check EVERY new injector part number with the IHC dealer and make sure they are for a 444E and not a 466E, I have had that happen 4 times to me.  The 2 injectors look Exacly alike but DO NOT work the same.  Also have you tested the wire harness from the valve cover to the IDM?  there could be a break somewhere.  One other thing to look at is the wire harness around the fuel filter housing, there is a sensor near the bottom of the filter housing that will seap fuel when it is bad; that fuel gets into the harness and swells the insulation around the wires and they short out. Also check the fuel return line at the back of the bad head, in a 97 there should be a screen in the fitting that gets clogged.  If I think of anything else I will get back with you.  Let me know what you come up with.  Thank you, MIKE