Won't start in the cold!

[boostnlb7]

my motor has 20,000 miles in it, brand new injeciotrs and cp3 pump, new FF too, 15w40 rotella T, original glow plugs and batteries that are almost 4 years old, well one is over 5 and the other is almost 4, its been 0 or below here and without plugging mine in at all it wont start, if i plug it in for a half hour it starts.. i know my batteries are weak because i can tell when im cranking it.. im not sure if i hav a combination of weak batteries and glow plugs tho.. when it starts it rattles like a cummins, but not if i plug it in all night..im gonna try batteries first..any other ideas?

[Wantamax]

Is this your first diesel/Duramax? If so, are you priming it correctly by removing the bleeder screw? If so, Im with everyone else about fuel being jelled up.

[Bosis21]

if its the batteries i would take it back to the dealer and put up as stink as you literally just bought it, and if they arnt jews and want repeat business they will put new batteries in for you as they probably already knew they were junk but just charged them up for a quick fix to sell the beast

[JZK01]

yes this is my first diesel, and i have loosened the bleeder screw once or twice but not everytime i prime it.. Am i supposed to lossen it everytime?

[07GMCLBZ]

Yea you gotta loosen it everytime until straight fuel comes out. Pump it about 10 times give or take and crack the bleeder.

[JZK01]

just gave that a try again, still wont fire up.. ill replace the fuel filter tomorrow hopefully that works even though im pretty sure it was done not to long ago.

[WVRigRat05]

Originally Posted by boostnlb7

my motor has 20,000 miles in it, brand new injeciotrs and cp3 pump, new FF too, 15w40 rotella T, original glow plugs and batteries that are almost 4 years old, well one is over 5 and the other is almost 4, its been 0 or below here and without plugging mine in at all it wont start, if i plug it in for a half hour it starts.. i know my batteries are weak because i can tell when im cranking it.. im not sure if i hav a combination of weak batteries and glow plugs tho.. when it starts it rattles like a cummins, but not if i plug it in all night..im gonna try batteries first..any other ideas?

Just built mine, took it to my guy to have some shit checked out I didnt replace the glow plugs, and 3 were shot. It was 8* this moring sounded like a champ with new glow plugs.

[Banjo Willy]

you have to have very strong batteries. They have to be able to spin the engine pretty fast ( about 150 rpm) and still have about 10.5 volts to fire the electronics. load test the batteries, if they won't hold a charge and pass a load test, replace both. Charge both overnight before installing them.

[boostnlb7]

Thanks guys.. My glow plugs hav 265k on them, i think.i will just replace glow plugs and batteries all im one shot.. That should do the job eh?

[2500-HD]

as a test over the past few days of single digits, i cold started a few times without glow plugs...cranked the same as if i waited the extra second.