LB7: Long crank before starting

[Righteyeblind]

My Fiancee's 03 LB7 is having to crank 5-7 seconds before starting.
I was getting a P0380 code but I think that has been there a while. I replaced both of the relays in the glow plug module which are way cheaper then buying a new module(Napa Echlin part#AR282) and all 8 glow plugs. No more code but still very long crank before start.
Balance rates are good
Logged rail pressure when cranking and it starts at 200 and slowly creeps up then when it hits 1400psi it starts, like it should right?
Checked FRP with DVT and will only hold 14k when 23500 is commanded.
No fuel in oil. Primer is not hard after you start it. I deleted mine and never checked the primer unless I replaced the filter so I am not sure if the primer stays hard all of the time unless you lose prime?
Im running to the parts store right now to get a non vented cap and pressurize the system and wanted to see if anybody else had any thoughts.

 

[rcr1978]

Primer is soft on them when running but only if theres no lift pump, I would say check return rates, rail pressure releif valve for leakage but doubtful, or air leaks like you stated.

 

[Righteyeblind]

Figured it out
I had my old fuel filter head off of my truck and stuck it on there. Starts no problem and holds rail when I crank it up at idle. Just an FYI if your truck does this check the small stuff first.

 

[TeaBagger2006]

that damn fuel filter head sure does cause a lot of grief for duramaxes. glad you figured it ou:thumb:

 

[Burn Down]

We need to ditch that piece of crap filter head... Tell Sage to start saving money, we need to mod the hell out of her truck to!

 

[rcr1978]

Cool it was something easy, it would suck to dink around trying to check return rates. What do most mechanics always do they assume the worst right off the bat