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Discussion Starter · #1 ·
I have had ATP tunes for a little over a year now. I have noticed sometimes when I mash the pedal, the desired fuel rail pressure is higher than the actual fuel rail pressure by up to 10k. Other times, it is right on under the same conditions. My logic of thinking would tell me that there is a fuel delivery problem IF it happened all of the time. This is not all of the time, so I don't know what to think.

It doesn't seem to matter what gear I am in, or whether or not I am already moving. I have tried this going up hills just to see what the pressure did, and it could go both ways.

When it does it, the truck falls on its face, so I know the reading is legit.

I assume if it was defueling I would also see that on the desired pressure reading, but I don't know.

I've noticed this before with smaller tunes, but I have been running the big tune this week. I don't usually beat it because I really don't want to rebuilt the transmission yet, so I don't do this often. It pisses me off a little when I do jump on it and it doesn't do what I need it to do though.

Mods are the usual entry-level mods. Turbo back emissions unfriendly exhaust, Transgo jr, EFI live with tunes by Rob.

Any thoughts?
 

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HERE SO I DONT GET FINED
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Sounds like you need a lift pump.
 

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Reign in Blood
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you are draining the fuel rail, a lift pump would help cure that. :thumb
 

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Discussion Starter · #4 ·
Well damn.
 

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Like said above, get a lift pump and you will be good to go
 

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Discussion Starter · #6 ·
Did you guys notice any mileage gains with the AirDog? Are the horsepower gains noticeable without stabbing the throttle? The truck is lifted 6" with 35's and the mileage sucks anyway, but I figured I would ask. I got next to nothing when I free'd up the exhaust.

Also, AirDog recommends the smaller pump (up to 500hp). Do you guys agree with that?
 

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I am willing to bet your fuel lines are collapseing where they go in and out of your fuel filter head. Mine did it too, the Airdog will fix the issue but I would replace the lines anyway. Also check the fuel lines where they go soft next to the tranny, they collapse there as well...
 

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Do the NBS trucks have the same issue with the FPRV opening when it shouldnt?
 

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Discussion Starter · #11 ·
I will check the lines.
 

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How close should desired vs actual be? Percent wise might be the easier way to answer.
 

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Discussion Starter · #13 ·
Should be almost identical from what I can tell. Mine is if I turn the tune down some and jump on it.
 
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