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Discussion Starter #1
Hey guys

My fuel pressure drops off after 1 bar of turbo boost.
Fuel pressure follows up to 3,5 bar and when I hit 1 bar boost it suddenly drops to 3 bar.

I have walbro 450 pump, adjustable FPR, an6 everywhere, modified in tank armature, thicker cables and relay for powering fuel pump

FuelPressure without vacuum is set at 3,0 bar. With vakuum around 2,2 bar.

When I'm cruising and hit a uphill my car gets bad AFR around 2,500 rpm. Jumping between 14-15 AFR when it should be consistent at around 14 or less.

Why does it drop off?
Return line too thin? FPR broken?
 

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Discussion Starter #2
I opened the tank and nothing wrong there.
My FPR is very hard to set pressure on. Like it's stuck.
I run E85 on HKS regulator which was bought by my tuner for this setup.
Will try a new one and check vacuum line.
 

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maybe it is stuck? i have seen another FPR with a broken spring, not sure what would cause it to break...but trying another one may fix it...also check if fuel line routing is correct
 

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Discussion Starter #4
maybe it is stuck? i have seen another FPR with a broken spring, not sure what would cause it to break...but trying another one may fix it...also check if fuel line routing is correct
I think it's so strange that my FPR would be broken.
Sinxe it's my tuners setup and he have a very big reputation about being very good with Subaru and evo.
But my guess is leaning to this too, that it's stuck/broken. Maybe it doesn't like E85 so much.
The routing is OK. Was working before until I put in Goat fuel E100. After this my tuner said that fuel is dropping off way to fast.
So I bought new fuel pump because he told me so.
But now both gas and E85 is loosing pressure at +1 bar boost

Will post update later when I'm at garage.
 

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Discussion Starter #5
Broken fuel pressure regulator.
Changed and pressure was more stable and went up with boost. Also kept pressure after engine shut down alot longer than before.
 
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