every morning when i go to fire up the greatest motor in the world(5.9 cummins) it sounds a lil hesitant but then fires up, i checked the batteries, cables and alternator..everything has a good charge... also i replaced the fuel filter as well thinking it may be bad... anyone have any advice? it has been getting in the low to mid 40's overnight also, maybe just is a little cold for the cummin's?

 

providing tha tyour letting the grid heat up b4 you crank it 40* is abit chilly for the 5.9 but nothing it cant handle... how old are your batteries? when it's cold sometimes they dont like to give up that energy as easy ontop of cold be rough on the batteries anyways. take it to advance and have them load tested... should give you an idea of what kinda health your batteries are in; other than that look for resistance in the starting circuit; i've heard that the starter contacts like to go bad (they're undersized for the ammount of current that's flowing through them and the arcing can cause a poor connection over time)