This is topic How Do I Set Fuel Pressure? Help, Needle On FP Gauge Jumps. in forum Tech Talk at Northern California Ford Owners .
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Posted by FivePTSlow (Member # 7682) on
:
http://youtu.be/r-BOoKBQHpE
I made a video to more easily explain what's going on. To put it simply the needle on the fuel pump gauge jumps around at idle. That makes it really hard to set the fuel pressure to stock level. The needle does this with my bbk gauge(liquid filled), & the gauge that's hooked up in the video(non liquid filled)
At idle the pressure is jumping from 28-34psi with vacuum line attached. With the vacuum hose pinched it goes to bouncing from 36-42psi. When revved it will jump to around 40 then drop down to a steady 20psi then return to bouncing around at the same numbers as above.
If I turn it up much more it will sit at 50psi steady @ idle. If I turn it down much more it will go to around 20psi @ idle & run super lean.
My fuel system is as follows:
Aeromotive 340lph in tank pump, wix fuel filter, factory lines from tank to engine bay, sn95 fuel rails, fms 42lb injectors, aeromotive adjustable 1:1 rising rate fpr.
[ 2014-02-24, 09:46 AM: Message edited by: FivePTSlow ]
Posted by FivePTSlow (Member # 7682) on
:
Changed the fuel filter today, still does the same thing.
Posted by 70 5.0Merc (Member # 13369) on
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My fuel pressure gauge bounced around like yours. It turns out my fuel tank vent was plugged. I unplugged the fuel tank vent and the fuel pressure is now steady.
Posted by FivePTSlow (Member # 7682) on
:
quote:
Originally posted by 70 5.0Merc:
My fuel pressure gauge bounced around like yours. It turns out my fuel tank vent was plugged. I unplugged the fuel tank vent and the fuel pressure is now steady.
I'll look into that, never would have crossed my mind. Although I've never noticed pressure in the tank.
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