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Discussion Starter #1
How much should a brand new stock fuel pump and new fuel filter be able to keep up with?
I put a new fuel pump and fuel filter into my fuel system and then filled the fuel tank up COMPLETELY to make sure that It wouldnt have an issue even if there was a crack in the draw straw. Started it up and it now idles at about 10-12psi. But the moment I accelerate moderately i drop to zero psi. I believe its all stock minus a superchips tow tune. The only difference I see with the new fuel pump is that the psi goes back to 10psi faster when I let off the throttle.
Is this normal?
 

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The stock lift pump is the real Achilles heel of the VP trucks, IMO.

10-12psi fuel pressure at idle is low. As a general rule, idle fuel pressure should be somewhere between 15-20psi, and WOT fuel pressure should not be below 10psi. Where are you taking your fuel pressure reading from, and how (e.g. mechanical gauge, electric gauge)? If your fuel pressure really is dropping to 0psi under acceleration, that is a sure fire way to damage / kill the injection pump. I would strongly suggest you disable the Superchips tow tune, and be very light with acceleration until you sort out your low fuel pressure.

It's normal to see a drop in fuel pressure during acceleration. The greater the fueling mods (tuners, large injectors) the larger the lift pump needed to keep up with the fuel demands. Even with a high flow external FASS or AirDog pump, some performance upgrades will pull the fuel pressure down 8+psi at WOT. The real problem arises when the lift pump has not been upgraded to match fueling upgrades. The stock lift pump cannot keep up, fuel pressure becomes too low, and the injection pump experiences cavitation.
 

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Discussion Starter #3
So this thing was able to be pushed open with my mouth. And of course its not a part anyone keeps in stock. Overflow valve strikes again.
 

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Yep, that would do it.
 

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Discussion Starter #5
Well I finally got a good gauge on this thing after swapping the fuel pressure overflow valve. I dont think its a fuel issue. Fuel idled at 16psi and went down to 9psi. Then I got this when it went into limp mode.
 

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Does the Wait to Start light come on immediately every time you turn the key?
 
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