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fuel pump housing cause fuel pressure drop high load?


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So i was getting my built and cam'd 05 lgt tuned and ran into some fuel pressure issues with it dropping around 6500-7200 @ 20psi boost. Was going for 25psi tune. At first they thought fuel pump so they replaced my dw65c with another and it helped a little but still dropping. They then tried a different gauge in my fuel lab fpr just to rule it out but still dropped. Then swapped out with new fpr but still dropped. Then tried bypassing the fuel controller to supply full voltage but still dropping. When pinching the return hose it builds the pressure needed but still dropped so swapped to smaller diameter return hose which helped a lot but would still slowly drop but not as far. They think it might be the filters or something in the pump housing restricting flow up top so stopped the tuning at 393hp 368tq and put a rev limit to where the fuel pressure would start to come down. Anyone hear of an issue like this with the pump housing? Injectors were doing great he said and the pump should be plenty. Also was getting some break up in high boost/load but he thinks it may be plugs that are gapped to .025 where he likes to do them at .022. Compression and leak down was done before tune and had great numbers. Any thoughts would be appreciated as i need to fix and get re tuned to break my 400hp goal.
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05+ LGT's have the fuel filter inside the tank, it's part of the plastic and is not easily replaceable (like it is on 04-08 STI's). Easiest solution is to buy a new OEM fuel filter assembly, $80 or so.


I'm trying to figure out an easy way to bypass the intake fuel filter right now, already have an inline filter wired in in the engine bay.


Fuel filter is inside of this



Here is what the filter looks like with a broken cover



Engine bay retrofit:


05 LGT 16G 14psi 290whp/30mpg (SOLD)

12 OBP Stock 130whp/27mpg@87 Oct

00 G20t GT28r 10psi 250whp/36mpg

22 Ascent STOCK

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Thank you so much for posting that! I've been searching and searching and couldn't come up with anything. Looks like I'll order that today and try to re gap the plugs this weekend to see if that clears up my break up in boost.
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