the engine compression does not effect the injector if you are get fuel or not but the engine compression dose effect if you want it it ignite the diesel fuel diesel ignite by the compression and by the cycle compressing the fuel and air so tight that the friction and compression kick the fuel off all low compression will do is puff out white smoke (unburned diesel) SEE on Hazts diesel which is the top of the line German industrial engine the piston goes up in to the head 2mm pass the block surface so that is way timing (it will knock out the valve) is important
on hazts they use a copper ring as a head gasket which i use some lead turn the engine by hand hit the lead then take it out to measure the thickness
hope the help some just remember you getting fuel or you are out of the pump or you might check to see if the pump is in the full open not close or half way close you need to have enough pressure out of the pump to pop the injector springs