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Discussion Starter · #1 ·
on my 05 lly duramax when i put i on a hot tune such over 200 hp setting and over and run it to hard it will limit me to 2000 rpm's,but i can reprogram it to the same setting and it is fine untill i run it to hard.my question is what causes that and what can i do to stop it,with out dangering the truck to much.:cool:
 

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Dose it set any codes? IT could either be a low rail psi code (p1093) or u could be limping the trans!
 

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What he said, I'd just like to personally welcome you to limp mode city! :D
 

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Discussion Starter · #4 · (Edited)
no it doesn't throw any codes that i know of:confused: ,it mite be tranny but i am guessing it is low fuel rail pressure.thanks for your imput.is the crowd big in limp city!!!:rof :Dalso what is some things i can do to clear that limp mode?
 

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Discussion Starter · #6 ·
i'm sorry,do what,and where can i get a shim
 

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Before getting into that, you should do a real time scan of rail pressure during a WOT run to verify that is your issue. I am betting it is. I'll walk you through the shim.
 

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Fuel Filter

:rockin
on my 05 lly duramax when i put i on a hot tune such over 200 hp setting and over and run it to hard it will limit me to 2000 rpm's,but i can reprogram it to the same setting and it is fine untill i run it to hard.my question is what causes that and what can i do to stop it,with out dangering the truck to much.:cool:
You might want to try the most simple and chepest first. A hot tune up and bigger exaust is great but you have to get the fuel there and the duramax computer monitors the fuel pressure. I had the same problem; I could only run 1500 rpm and the check engin light was on. A new fuel filter and code re-set fixed my problem. I do and recomend to everyone to replace the fuel filter every 20 tho. miles
 

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Discussion Starter · #9 ·
:rockin

You might want to try the most simple and chepest first. A hot tune up and bigger exaust is great but you have to get the fuel there and the duramax computer monitors the fuel pressure. I had the same problem; I could only run 1500 rpm and the check engin light was on. A new fuel filter and code re-set fixed my problem. I do and recomend to everyone to replace the fuel filter every 20 tho. miles
i replace the fuel filter every 10k and it's due in the next couple of days.but it has been doing off and on over the last couple of months or since i got it.guess i'll have to get the sun coast tranny and then put more fuel to her.:confused: allthough it runs great when it doesn't give me the code.thanks for all the help,james
 

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Bull is right. I overlooked the fuel filter. But the code set is really important here. Autozone will pull it for free if you don't have a scanner.
 

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Discussion Starter · #11 ·
thanks for all the info you guys are great!!!travelswithcharly you said something about a shim where can i locate one it would be most appreciated.
 

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I just want to help solve the problem. There are several possibilities, and doing a valve shim is not the easiest thing to do (and easy to screw up), so just trying to avoid "lawn dart" approach, and narrow down the cause, before proceeding.
 

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Discussion Starter · #15 ·
I just want to help solve the problem. There are several possibilities, and doing a valve shim is not the easiest thing to do (and easy to screw up), so just trying to avoid "lawn dart" approach, and narrow down the cause, before proceeding.
i appreciate all the help and info you guys got me allready.i'll try to narrow my problem down to a more passific thing.thanks again.ps i scanned for codes but it didn't have any codes.
 

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i appreciate all the help and info you guys got me allready.i'll try to narrow my problem down to a more passific thing.thanks again.ps i scanned for codes but it didn't have any codes.
ok, no codes.

Oddly that does help. The dmax is prone to laydown under high fuel loads. Some FPRV's will 1093, and others do not. Mine has fallen into the latter category.

My symptoms are as follows: Under a WOT load, as the rpm approaches higher levels, the truck just seems to give up, and the rpm fades back, with a lack of power. When I completely unload it, the problem has dissappeared, and I can just go on my way. Elusivity.

Does this sound familiar? Or does yours stay in a limp mode?
 

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Discussion Starter · #17 ·
it does the same thing but it stay in the 2000 rpm governer but it has full power in that range,then when i reset it it runs fine.i noticed it does it more often at higher speeds,and when it is under hard throttle to long....if that makes sense!!!!
 

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and one more question. When it happens, does it scare the poody out of you, like something broke or blew up?

Or does it just gently lay down?

Do you know what it feels like to limp the tranny?
 

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Discussion Starter · #20 ·
i shouldn't say i reset it i reprogram the truck and it goes away untill the next time...yes i know how it feels when the tranny goes in limp mode and it feels about the same,it's kind off hard to explain but when it is under hard throttle it will run allright untill you let of off it and when it gets beneath 2000 rpm then you realise it has the governer,that is where it really differs from the limp mode.i guess it has me stumped because at first i thought it was the limp mode but i'm thinking it is more fuel related now
 
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