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Fuel pressure drop after engines off

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Old 12-20-2006, 12:33 AM
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Fuel pressure drop after engines off

I just installed a lift pump and an electric fuel pressure gauge. At idle it has 12 to 14 psi. When accelerating uphill it drops close to 5 psi. When I cut the engine off the electric fuel pressure gauge shuts off also. In the 6 or 7 seconds it takes to turn the key back on and the electric fuel pressure gauge to settle down the fuel pressure has already dropped to zero. Is that normal or should the pressure drop slower ? Thanks
Old 12-20-2006, 12:35 AM
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Mine drops like a rock as soon as I shut the truck down, I wouldn't worry about it.

Jeff
Old 12-20-2006, 01:21 AM
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Mine does the same thing. But if I were you I would get the Vulcan Big Line Kit and L/P relocation kit. My pressures were the same as yours. After I put the Kit on I could not pull it down past 12 psi.
Old 12-20-2006, 07:40 PM
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The drop is normal at shutdown. You're basically powering off the gauge and lift pump.
Old 12-20-2006, 07:41 PM
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Welcome to DTR

Pulling the pressure down to 5PSI is a warning sign. Replace the stock LP with an aftermarket set up when it gets lowers. Walbro or FASSII. I can't pull my FASS below 15 PSI.

No more stock LP's.
Old 12-21-2006, 08:56 PM
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Originally Posted by derf464
Mine does the same thing. But if I were you I would get the Vulcan Big Line Kit and L/P relocation kit. My pressures were the same as yours. After I put the Kit on I could not pull it down past 12 psi.
That's exactly what mine did after I did the Big line kit. I hope it keeps the vp cooler too.
Old 12-22-2006, 03:01 PM
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If your fuel is getting hot, you can plumb a simple cooler in front of your radiator. I run the return line fuel through mine for 0 psi cooling.
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