1954 cat 112 moter grader

Howdy fellows
Been helping my neighbor work on his grader . He got every thing back togeather finslly got around to pulling it off this afternoon and it finnaly got the injectors primed and started running but #1 cyl. isnt fireing right. When he crackes #1 injc. line it quits fireing as it should and the engine smooths out like it is only running on 3 cylinders. When the line is retighened the engine starts making a loud poping sound. There isnt any white smoke like if it wasnt fireing but the engine dosent have the power of all 4 cylinders. All the work that was done to the engine was a complete head rebuild including injectors.
Any thoughs out there in catepillar land.
THANKS
Richard

Try taking the side off the injection housing & see if the pump plunger gear is in time with the rack bar. They both have a notch on them & the pump gear usually had a little ball on the gear too so check it out as they could be out of time. Also if things look ok then try switching the pump say with the # 4 pump & give it another try. If the miss follows the pump then the pump might be bad. Also if it fires ok on # 4 then check the lifter screw height on #1 & see if it,s ok.Another thing is recheck the valve clearance too to make sure it,s ok.They should be .010". The lifter screw height should be 1.736" with the # 1 cylinder on TDC on the firing stroke.To check for sure if your on # 1 watch the lifter screw & when it,s coming up on #1 the lifter screw will just start up from the bottom poition of the housing & the flywheel mark has to be on the pointer then to set it.Make sure you turn the engine CCW from the flywheel end. Another thing is if you pass the flywheel mark a little don,t just back it up to the mark but back it up a ways & then come back up to the mark & stop directly on it.