desired fuel rail pressure vs actual fuel rail pressure

Teamvi

New member
Oct 26, 2011
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desired fuel rail pressure vs actual fuel rail pressure
I have a stock cp3 and injectors on my 05 lly, if I really get on it my desired fuel pressure will be around 23k my actual will stay there for a little then drop down. I just installed a new fass 150 on it also? any ideas why I cant hold the fuel pressure? also have the ppe race plug
 

02greysixer

Active member
Jun 4, 2011
1,829
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38
North Central FL
I am battling this issue as well. Mine is injectors. I have wanted to upgrade to an lbz pump anyway so I did to rule out the pump issue. If I go more than 2500us of pulse my actual starts falling @ wot. I know It's not my pump or fprv and the return test on my injectors was high. 144 ml is the max return allowed for the test from all 8, I had like 130ml.
 

S Phinney

Active member
Aug 15, 2008
4,008
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Quncy, Fl
Also check your pickup in the tank and tank for black algae. It is a nasty gel substance that restricts the pickup and cuts of some fuel.
 

Teamvi

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Oct 26, 2011
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Choose your power level by using the up and down arrows. When the
program you want to load is displayed, press ‘​
Y’ to select it. All power
levels represent additional horsepower increases possible at the crank:
a. Economy Power = +50hp, 97 ft. lbs.
b. Heavy Tow Power = +90hp, 160 ft. lbs.
c. Light Tow Power = +120HP, 200 ft. lbs.
d. Street Power = +160hp (LB7), +180hp (LLY); +265 ft. lbs.
e. High Power* = +221hp, 332 ft. lbs.
f. Max Power** = +270hp, 349 ft. lbs.
g. Race Power 1** = +300hp, 362 ft. lbs.
h. Race Power 2** = +315hp, 383 ft. lbs.
i. Race Power 3** = +330hp, 503 ft. lbs.
j. XTREME POWER** = +350hp, 530 ft. lbs.

*Automatic Transmission must be upgraded for maximum performance and to withstand the increased
power, and manual transmissions will require clutch upgrades. Contact ATS for help upgrading your
LCT1000 Automatic Transmission or your ZF-6 6-Speed Manual’s clutch.
**Further modifications to the fuel system (such as ATS Injector Nozzles and Twin CP3 Fuel System) and
turbo (such as ATS’ line of Aurora Turbo kits) must be made in addition to the power train upgrades above
to successfully achieve these power levels.

I am runnin on the street tune its in blue
 

NC-smokinlmm

<<<Future tuna killer
May 29, 2011
5,199
362
83
At Da Beach
Its nornal for the rail pressure to drop a little during a wot run on a tune that big. A couple thousand psi off desired is ok. When did you change your fuel filter last? What brand did you use?
 

c20elephant

C20ELEPHANT
Apr 25, 2013
2,065
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Phoenix, Arizona
You have a quite a restriction at the fuel pickup assembly in the tank and 2 inside the stock fuel/primer assembly. Delete the stock water/fuel separator filter, NO...
 

Teamvi

New member
Oct 26, 2011
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So are you saying no to delete the stock fuel filter? I have a fass 150 with the filter and the water separator on it? Would a fass drawstraw help any?
 

c20elephant

C20ELEPHANT
Apr 25, 2013
2,065
0
0
Phoenix, Arizona
So are you saying no to delete the stock fuel filter? I have a fass 150 with the filter and the water separator on it? Would a fass drawstraw help any?

Fill out your signature with what modifications you have done to the truck, a draw straw would help. Did not know you had a lift pump, you can delete the OEM pump primer assembly if you want....