03 Cummins low rail pressure issue

STROKETHISF350

STROKETHISF350

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I've been chasing a low power problem for a while now and after finally getting to find time to throw the solus on the truck I found that the rail pressure will not go above 19k. The weird part about the situation is that the demanded rail pressure doesn't go above 19k psi either. What would cause the truck not to ask for full rail psi at wot, the test was done with the smarty on level 5 if that helps. Does anyone have any idea what the problem might be? Thanks in advance.
 
You're obviously above de-fuel temps, so now we're looking at possible high rate of injector return flow or possibly the CR bypass valve not holding. Open the valve on the rail and check to see if you have fuel sitting on it.....if so, it's popped and most times they don't re-seat. That should narrow down the issues.
 
The injectors have 60 k on them so it doubtful but possible I would guess the relief valve could be suspect but that won't solve the question of why won't it command for over 19k psi
 
a little update on my issues, I was messing around today and decided to do a cp3 return rate test and I found out something interesting. with the key on and lift pump running fuel steady flows out the cp3 return. is this normal? Im unsure but I would say not, also I got 150 ml of fuel in 15 seconds of running out of the return. someone with some knowledge please chime in as im very anxious to finally get this thing to run 100%.
 
Not quite sure, anytime I have done return flow test cummins says to measure while engine is running. I am pretty sure there isn't supposed to be that much fuel flowing past return. I think, it's been a while, spec is 90cc in 30 sec max. But I may be wrong on exact spec.


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I was under the impression max rail should be mid 20s I put another cp3 on it and wot it maxes out at 19k and with the FCA unplugged at idle its close to 17 k, I'm kinda lost and I'm starting to think mabey the computer is in limp Mose possibly
 
unplug the FCA and injectors so it doesn't start and monitor with a hand held viewing rail K, it will peg the rail during cranking (24K). if the rail return is getting hot its doing its job. if so, then its in the head.
 
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