Duramax will not start

[Magman]

2003 Duramax on occasion will not start after an overnite. The hand pump is hard as i have installed an aux electric pump. After 5 min or so, it will start. Any suggestions?

[rapidoxidationman]

any codes stored?

[Magman]

Never any codes at least not on my scanner.

[Kennedy]

How are the hot starts?

Please define "after 5 mins" What is happening during these 5 minutes? Cranking intermittently, walk way and come back?