LLY: no go over 2000 rpm

T

TCHIGGZ

New member
Mar 12, 2017
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Need help!

Have read a bunch of post, and cant find and answer. I have a 2005 Silverado 2500hd LLY. It wont go over 2000 rpm once I reach operating temp. I have no codes. I have changed the fuel filter several times. I have changed the fuel filter housing. I have changed the fuel pressure relief valve twice to a racing plug. I have changed the fuel pressure regulator. And I have changed the air filter. I pull over, turn key off for 3 minutes and it runs fine, until it gets warmed up and you give it to much pedal. Any real help is very much appreciated. Thank you in advance.
 
2004LB7

2004LB7

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Dec 15, 2010
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What code reader are you using? Sounds like limp mode. That should turn on the CEL
 
D

Digmax

Member
Jan 23, 2016
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Need to monitor desired rail vs actual rail. Sounds like a fuel limp

Sent from my SM-G935V using Tapatalk
 
Harbin_22

Harbin_22

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Dec 4, 2010
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No one is going to be able to guess the correct part to fix this. Either get a scan tool and start diagnosis, or take it to someone who can. This could be something very minor, or really expensive to throw parts at
 
2004LB7

2004LB7

Well-known member
Dec 15, 2010
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TCHIGGZ said:
That sucks, runs great when cold.
Click to expand...

That is likely due to the fact that diesel is "thicker" when cooler and thus doesn't leak through the injectors, cp3 or pressure release return as much. This allows the cp3 to maintain higher pressure and no limp.

When it gets hot the fuel leaks past at a higher rate. When this plus the normal fuel use exceeds the cp3s' ability to keep up then fuel pressure drops and the engine goes into limp mode
 
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