Truck Repair: celect electronic m11 cummins, screw out, jam nut

Question
Hi. I have a m11 cummins in a erf.The engine is missinr on no 6 have changed injector and engine ran ok until it was reved up then the missing started again.Changed injector again and it done the same again.Can you enlighten me on what the fault my be.

Answer
Make sure it is the right injector by the ECM data or you adjusted it wrong.
On the Celect,you adjust valves & inj on same cyl.The mark A is now 1-6,B is 2-5, & C is 3-4.Valves are Int 0.014 & Exhaust is 0.027.The injector you hand tighten screw until injector plunger bottoms out.Back screw out 2 flats,ie turn corner of lock nut to align with the riviot in the rocker lever(pushtube side),then back out screw two "corners" then tighten the jam nut down.Adjust the Injector first,then the valves.