LBZ rail pressure question???

syrupdawg

syrupdawg

GA Diesel Mafia
Joined
Mar 16, 2008
Messages
1,792
we put a ppe on a LBZ today on level 6 and it is throwing the 0087 code which is low rail pressure correct? We didnt put the shims in the rail yet will that help? When at full throttle the rail pressure drops to 13K. Im not a duramax guy so im not sure what they run at WOT or just idleing. Any help would be appreciated...I was just trying to figure out if it could be the cp3 or if it just might need a lift pump to give the cp3 more fuel. Im sure you duramax guys know more about it than I do. Thanks
 
idle Dmax runs 4800-5100psi

LBZ WOT run 25,000-26,000psi

you need shims and lift pump to be able to hold rail pressure..

the P0087 trips when the difference between actual and commanded(asked for) go beyond a set point in the ECM..
 
alright the truck was only ideling around 3900 to 4000 PSI...do you think the cp3 could possibly getting weak?
 
When is the last time the filter was changed?

Always start with the easy one.
 
Had this same problem on a truck with 20000 miles dealer replaced fuel rail said it had an internal crack but this was after we had shimmed the rail and put a lift pump on
 
the truck doesnt run bad or anything but the rail pressure definately drops on the guage and is running about 13-15K at WOT. The only thing is it throws the code so obvisioly there is something wrong???
 
syrupdawg said:
the truck doesnt run bad or anything but the rail pressure definately drops on the guage and is running about 13-15K at WOT. The only thing is it throws the code so obvisioly there is something wrong???
Click to expand...

yep loosing you rail pressure and its whining about it..

either lift pump, or drop down a tune.
 
I ran PPE's stage 6 on my truck (w/ no lift pump) and it drained the rail severely...by about 13,000psi under commanded.

Like malibu said...either put a lift pump on it (probably still need to shim the fprv after) or crank it back.
 
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