Hi all, I have a 08 GMC Duramax with around 90K on it. Recently I've had to crank it longer to get it to start. Once it starts, if I restart it, it cranks right up as normal. If I let it sit, I have to crank it for a while to start. I can't find any fuel leaks, fuel filter serviced regularly. It seems like it'* loosing fuel PSI, I'm not that experienced with the Diesel as I'm a Motorcycle Tech. Any help or suggestions is greatly appreciated.
Joe

Do Duramax'* have lift pumps? Meaning, a pre-pump before the main pump? I know the bigger Cummins engines have lift pumps. They are designed to prime the fuel system prior to starting.

they take longer to get going in the cold, is this your first winter with it?

Could have a couple of bad glow plugs but that usually sets a check engine light

I,ve own it since 08 lived in Very cold weather for a while and never had this problem, about a year ago I replaced all 8 glow plugs. I really think its a fuel PSI problem or maybe air in the fuel system?
Joe

most diesels are sort of self bleeding after they run a while the air is worked out. not real familiar with that specific engine, did you take pressure readings and compare to specs, see if it holds there for a while?

battery condition seems to make a difference too, i have a 550 at work that was hard to start but it was actually the batteries needed charged, they have to warm the engine and crank it and power the pump all at the same time.

Up date, tried bleeding system at filter housing, had to pump it three times before I got fuel at the bleed screw. Now it starts as it should. The million dollar Question is where'* the Air coming from, no visible leaks.
Also interesting enough, "It is time for Batteries" 6 years old and cranks slow on cold mornings this could also be part of the problem.
Thanks for all the suggestions, I'll keep you updated on what the new batteries do.
Joe

Air could have come from the last filter change, or fuel got low, and sucked up some air.

Here'* what I'm being told now, the air is coming the o-rings at the fuel filter housing? So tomorrow I'll replace filter and o-ring and see if that fixes the problem. It makes sense to me, as the filter is do to be changed.
Thanks for all the help
Joe