Changed fuel filter and now it wont start,,,how

You may have air in the injecter pump.You need to crack the lines loose at the top of the injecters.Just loosen as many as you can reatch.Back them off about 1-1 1/2 turns of the nut.Crank until you see the dielel squirting out without bubbles and re-tighten them individualy as the air is bleed out.When changing fuel filters try and fill them with disel as high as you can and then try to manualy prime the system while opening the bleeder valves.Well hope this helps and good luck.