Not starting like it should???

[imaaron44]

So i have a 2003 with the 5.9 and was curious if anyone can give me some possible answers to my questions... So when i try to start the truck it cranks for like 3-4 seconds before starting any suggestions?
ps I do let the glow plugs warm up and the light for that does go off before cranking...

 

[Bob V]

Before anyone jumps on you. The Cummins motors have grid heaters, not glow plugs. The CR (Common Rail) motors will take a little more cranking to fire because the high pressure pump takes a bit to get up to pressure. However, longer that normal crank times can also be a sight of other problems, like a bad injector(s). How many miles is on it? Do you know any of the service history?

 

[imaaron44]

oh i see ok haha sorry its my first diesel... it has 241k and im not sure about the history

 

[Bob V]

If the injectors have never been replaced they might be getting to the end of there life. Fuel and filtering quality has a lot to do with injector life. Also, if it ever had a pressure box on it, it will shorten injector life.

 

[Hoefler]

Also, tired batteries will cause abnormally long crank conditions as well. My 05, 08 and 2010 would act like that when I had one bad battery.