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So I have a 2006 LLY w/a bully dog programmer, afe intake, and 5" MBRP turbo back. When I am in Extreme setting and hammer down, I get a P0087 (fuel rail pressure too low) around 90 MPH. When in the Performance setting this does not happen. Any ideas?
 

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I'm That Guy...
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You are probably draining your fuel rail, if it has a monitor watch desired vs actual fuel rail pressure. Either that or you could be popping your FPRV.

Ideally I would data log it if you have a friend with an EFI Live v2 and we can give you a better idea what is causing the code.

There are many other possibilities.

When did you change your fuel filter last?

If it's the fuel rail being drained, I would recommend adding a lift pump like the AirDog2 165.
 

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Lack of lift pump would be my guess. Looks like its time to spend some $$$$$.
 

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As tony said, fuel filter fist (although doubtful with your extreme tune being used when it happens)

you're more than likely draining your fuel rail. Edited cause i'm stoopid
In my mind the best out is HANDS DOWN the Airdog II 165, plus the added filtration adds to the fact that it is strongly recommended by most (if not all)
this should alleviate your issues :thumb
 

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I'm That Guy...
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You can temporarily fix the issue by either shimming the fprv with a PPE shim kit, or using a PPE race plug in place of the fprv. I say temporarily because you're already putting strain on your cp3, so you're to the point of needing a lift pump.
This is not accurate. These are two entirely different issues, a shim kit will do nothing for a draining fuel rail. The FPRV shim increases pressures required to pop the Fuel Pressure Release Valve.

The issue on big tunes is the pw on the injectors is too big and they stay open such a long period of time the cp3 is unable to maintain rail pressure. Once that desired vs actual rail pressure hits a certain mark it will set off the P0087. There are many things including the FPRV that will set the same code off, but you can usually have idea what is causing it from a good data log.
 

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My guess is lift pump
 

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Lift pump for sure, i bet you are dropping at least 5k below desired on wot. Stock lift pumps are only good to about 90HP over stock, then they cant keep up and the rail pressure drops.
 

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^^^ yes what stock lift pump? Never seen a dmax with one
 

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Wait there is a stock lift pump!!! Must be a special edition from the factory!


Sent from my Autoguide iPhone app...
 

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My bad guys, i was under the impression that they had a transfer pump in the tank like the dodges. Northwest Coal Roller you dont need to be a dick! Im sure you have made a mistake once or twice
 

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Haha thanks man. So just so i have it straight, the stock cp3 without a lift pump will only hold rail pressure up to somewhere around 90-100 over stock right?? Adding an air dog or fass you can hold rail pressure at higher levels?? What point do you need to upgrade your cp3?
 

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Haha thanks man. So just so i have it straight, the stock cp3 without a lift pump will only hold rail pressure up to somewhere around 90-100 over stock right?? Adding an air dog or fass you can hold rail pressure at higher levels?? What point do you need to upgrade your cp3?
Depends. My max effort tune didn't throw the low rail pressure code without a lift pump.
 

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I know LMM's can run hotter tunes.. What about LB7?? Different model CP3 right?
 

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I'm That Guy...
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Haha thanks man. So just so i have it straight, the stock cp3 without a lift pump will only hold rail pressure up to somewhere around 90-100 over stock right?? Adding an air dog or fass you can hold rail pressure at higher levels?? What point do you need to upgrade your cp3?
Every truck is different, even stock a lift pump is helpful and reduces strain on the injection pump.

Some injection pumps are stronger then others and it's not year by year.
 

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Get a lift pump on your truck..Hot tunes demand lots of fuel and the CP3 cannot supply enough fuel with tunes over 100 HP usually.....
 

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Take Dustin up on his offer. Buy a Lift pump, and PPE race valve. Forget shimming it, like I did!!! I should have blocked off.
 
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