i have a M1008 CUCV (1984) and i am having problems with fuel delivery to the injectors. there is good flow out of the fuel filter supplying the inlet to the injector pump. it appears to be the fuel injector pump servo piston. i disconnected one of the fuel lines off the pump, pressed the accelerator and no increase in flow out of the discharge of the pump. any info on what to do with this problem? if i have to pull my fuel injector pump, can i replace it with another off a 1986 chevy 1ton 6.2 diesel? what extra parts should i have on hand before starting? also, what is a substitute for "calibration fluid"?