Harder Cold start

T

TxDiesel007

Uncommon CR problemed
Joined
Jul 15, 2007
Messages
1,648
The thread below pretty much sums up what my 05 is doing..

Hard cold start - Competition Diesel.Com - Bringing The BEST Together

But for a more detailed explanation, here goes.. Truck sits for a day or so, and i go to start it.. It cranks over for a good while, normally to the point where the starter sort of "cycles" again... 6-8 seconds im guessing.. and it fires right up... Sort of like its losing prime or pressure in the lines.... truck can sit for a while and it will fire up again real easily every time (8 hours for work) hot or cold engine its just the first start of the day that it gets finiky.. Oh theres no white smoke either... its been doing this for three days now... truck runs and tows really well other than that.. i have zero issues with it (knock on wood) other than the hard morning start... and its south tx so its not freezing yet.. or ever for that matter

truck does have a new FCA (less than 10k miles)
New injectors (less than 10K miles)
GDP 2 micron filtration
NO DTC codes other than a P0541
oil change and filter changes less than 1k miles ago
fuel is always from same station

I do question tho.. what is a PRV? (pressure relief valve im guessin?) where does it go? how does one tell if its bad?
and NO i did not change the connector tubes when i put injectors on..
Also, how could you tell if the in tank LP is going bad? it sounds pretty darned strong even with 210K miles... and truck runs smoothly?

does anyone have an idea which of the three is the more likely culprit?

thank you in advance!
 
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ok after searching more..

rail relief valve? interesting.. where is it located?
 
Im having the same problem, truck is a 2005 with 215k miles and 100% stock. The longer it sits the harder it is to start. No CEL and no codes!
 
PRV is at the end of the fuel rail, towards the radiator end
 
Is this problem really that damn uncommon???? I guess its true... I have uncommon problems with commonrail trucks...

Anyways fwiw..injectors are coming off to be tested.best insurance while the freakin things are still under warranty...

For now added diesel kleen to see if it aint some crap stuck on filter canister etc..

Gonna check canister later.... No way to test prv... So im s o l....
Gonna check crossover tubes and hell why not.. just replace em while injectors r out..
 
Batteries, bad connection, poor starter or a combo of some sort. Try that first before you start chasing a ghost.


To check a PRV you use a rail plug. That's what's its purpose is for from my understanding.
 
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Have you swapped FCA's? I would do external things that are easier before automagicly doing open heart surgery. You catch fish the short cast sometimes.
 
Brand new fca... But have not swapped out the old one yet...

Thank you very much
 
Gibson said:
Batteries, bad connection, poor starter or a combo of some sort. Try that first before you start chasing a ghost.


To check a PRV you use a rail plug. That's what's its purpose is for from my understanding.
Click to expand...

rail plug

read on those.. 22 bucks from some JL diesel or something like that.. Although it was advised not to do so unless you have a RP gauge.. stuff of which i dont have (but now noticed i need:nail:) because im sinkin my toy money into a 12V....

so in doing so, and if i get this correctly, if a PRV is bad, and i put a plug on there.. the truck should fire up immediately (assuming all other factors are good?)

more so, i thought the PRVs job was to actually relieve excess rail pressure to protect the injectors, Does this mean that even when the truck is off it would "bleed" pressure and leave the injectors with nothing? it makes no sence really, since i was under the impression injectors needed to leak a little to self lubricate... anyways.... So is it possible a smarty on 5 would pop the darned thing? Im guessin 210K on the original could do it as well...

anyways.. sincerely.. thank you for the help... i appreciate it... :)
 
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Rail plugs aren't meant to run all day everyday. But are meant to check if a PRV is not operating correctly.
 
Gibson said:
Rail plugs aren't meant to run all day everyday. But are meant to check if a PRV is not operating correctly.
Click to expand...

understood sir... so is my above post correct in the way im thinkin it works? If not please correct me....

:thankyou2:
 
The PRV only 'pop' at a certain psi which is around 26,000psi. It should never open unless pressures go above that in the injection system.
 
What data is the Ecm seeing from the engine fan with the engine off?
 
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