Confused on where to start lookin/testing

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
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Phoenix Az
ok so after loggin some runs in the diesel with mikes (mmlmm) race tune im definitly runnin out of fuel on the taller gears. Now heres where my question comes in.

The injectors are alright. two are right or close to 4 (+/-) but rest are 2 or lower.
CP3 with a command of 23,000 (160) will hit 22,000 to 22,500. no sure if thats ok

ill post my logs here when i get on the other computer that has it all but im not sure where to go with this?

do i do a bottle test? ive heard on the LB7 that its really not a likely cause

Whats the difference in FPR and FPRV? ive never quite got the difference between the two on my motor, jsut maily what the FPRV does on the LLY. Can i check mine somehow?

Ive tried some searchin around but its kinda leavin me confused on what i find and i never really find the answer i think i need.

Im kinda leanin toward the CP3 bein done but think it could be the FPR/FPRV (which ever it is) as mine surges enough to notice but nothing thats like a lope tune.
 

paint94979

Beer Nazi
Sep 18, 2006
11,715
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ok so after loggin some runs in the diesel with mikes (mmlmm) race tune im definitly runnin out of fuel on the taller gears. Now heres where my question comes in.

The injectors are alright. two are right or close to 4 (+/-) but rest are 2 or lower.
CP3 with a command of 23,000 (160) will hit 22,000 to 22,500. no sure if thats ok

ill post my logs here when i get on the other computer that has it all but im not sure where to go with this?

do i do a bottle test? ive heard on the LB7 that its really not a likely cause

Whats the difference in FPR and FPRV? ive never quite got the difference between the two on my motor, jsut maily what the FPRV does on the LLY. Can i check mine somehow?

Ive tried some searchin around but its kinda leavin me confused on what i find and i never really find the answer i think i need.

Im kinda leanin toward the CP3 bein done but think it could be the FPR/FPRV (which ever it is) as mine surges enough to notice but nothing thats like a lope tune.

if your CP3 will hold 22,000-22,500 psi your CP3 is a VERY strong CP3
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
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Phoenix Az
are you saying that in the logs you command 23k and drop off to 22-22.5 during a run?

if your CP3 will hold 22,000-22,500 psi your CP3 is a VERY strong CP3

this is at idle. when i go into the DVT area on EFI and put in 160, the log will show a desired pressure of 23,000 and actual is 22,000. all at idle, no throttle in put and in park
 

x MadMAX DIESEL

<<<< No Horsepower
Dec 30, 2008
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Lexington, Ky
Whats the difference in FPR and FPRV? ive never quite got the difference between the two on my motor, jsut maily what the FPRV does on the LLY.

FPR is the fuel pressure regulator, its on the back of the cp3 and regulates the fuel.

FPRV is the fuel pressure release valve, it opens up if the rail pressure gets too high to save rail from blowing up along with saving other major engine parts. That like you said isn't usually needed to be blocked off/shimmed on an lb7 because they don't pop open as easy. (I think they are electronic on lb7a) were LLY+ are mechanical and mechanical stuff wears out and gets easier to blow open with time.

Try changing your fuel filter befroe anything else, if thats not the problem owell you got a brand new filter :thumb:
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
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Phoenix Az
filters only have 5k on them and even with new ones i dont dont see much difference in pressure
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,670
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Phoenix Az
heres the log of teh race tune, ignore the file name, something mike and i are tryin to figure out
 

Attachments

  • carter race tune wrong os.zip
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