starting problems

[strokerman12]

I have a 04 6.0 liter it has a programmer but if i dont plug it in in the winter it wont start it seems like it has a dead battery but if i plug it in it will start but today it barley started it cranks really slow i probably only drive it once a week.

[TurboSevenThree]

It should be plugged in for 1.5-3 hours. That plug-in is an electric block heater. I'm not sure if you know how the diesel engine works but basically, it compresses air hot enough to ignite fuel (hence injectors, and no spark plugs) So when you start it cold without it being plugged in, it is sucking in that COLD air and trying to compress it to cherry red, with cold fuel, and cold thick oil... And it cranks slow because at a diesels crazy compression ratio's, that is a huge drain on the batteries, they aren't dead it's just very hard on them.

If it is over 40 degrees it doesn't really need to be plugged in, but if you only drive it once a week... i would plug it in.

I wouldn't expect it to start if it sat for say 6 days and wasn't plugged in before trying to start it.

If you can't plug it in, or not for long enough, or forget, etc. use those glowplugs When you turn the key on and "wait to start" wait about 40 seconds after the light shuts off, and do this cycle twice or more (i do it 4 if it sits for a week and is 20 degrees) and it should have an easier time starting.