2006 6.0 Fuel Pressure bleed down

[BigOrange]

Hey fellas - think I know my answer but figured it wouldn’t hurt for a second opinion...but recently my ‘06 3500 6.0 sat for a couple days and when I went to start it, burped and didn’t fire.  Second key turn it started, stumbled for a couple seconds, then it was fine.  The next morning it fired on the first roll but did have the stumble for a second or two - - - so I started thinking fuel pump.  

 

However throughout the day it fires up just fine, even after sitting from morning till lunch, etc.

 

So I bought a pressure gauge and got to testing...

 

I’ve got 55psi with key on, not running.  Steady 60 psi at idle running.

 

- key off it drops back but holds 55

- after 10-15 mins drops to under 50-48

- hour to two hours drops to 30

- by morning dead 0

 

I would think it should hold SOME pressure even overnight, so thinking bad check valve or pressure regulator - both of which are in the pump on an ‘06.  Maybe draining off enough pressure/fuel overnight that even though it bumps to 55 right off the bat, there could be air or space still in the system at the injectors which is why the initial burp/stumble since it doesn’t last very long at all.

 

 

- so I’m assuming I’m likely looking at a new pump assembly since with 265km on the clock, even fixing something minor (valve/regulator) would be a bandaid.  BUT.... should I also be worried this pump is giving me the telltale “wink” that it could crap out any day/time or could I possibly run it for while doing the double key cycle truck in the morning since that seems to help.  Just spent a bunch of $$$$ moving so if this is the only issue I have to deal with for a bit till I can change it out that’s fine, but if the pump is saying “change me now!” So be it I guess.

 

Thanks guys!!

[asilverblazer]

Same thing on my 06 Caddy, changed the pump, cured the problem. 

 

There should be no pressure loss overnight. My symptoms were extended crank times. But diagnosis, revealed similar condition, fuel pressure not holding with pump off.

[BigOrange]

Thanks Asilver - I’m 99% that changing the pump will be the solution.  

 

I’m now just wondering how much of a gamble it is to continue on doing a double key flip first thing in the morning for a little while.  I’ve read that guys have had similar issues for years before there is any real pump failure.  But that typically if these types of issues start showing up the pump itself could just take a crap at any time too based on its age.  ?

[Markmx6]

On my silverado I did the key dance for a month or so, but then the pump just died on the freeway. Better to just replace it when you get to choose the when and where...

[BigOrange]

I hear you Markmx6 - I know that's the right answer for sure.  The joy's of owning an older truck of course, but this way I don't feel so bad when a bang a few trees of her in the bush vs. brand new paint!