VG30DETT FuelPressure drop help!!!

[viet90tt]

my car would drive fine until it warms up and boost hits, the fuel pressure drops under boost (we hooked up a fuel pressure gauge and tested the car while driving. I switched out the fpr and also Grounded the OEM fuel pump so it has a straight 12v running to it, and same issue. Replaced with a walbro and same issue. The car would boost fine a few times as it warms up but after 15 minutes of drive time it would restrict all boost and restrict rev, I would have to drive the car without boost. Also on cold start-ups the fuel pump is quite and after the car has warmed up the fuel pump would start whining, (known problem for walbro fuel pumps.) Any help would be greatly thanked!

[Timbo_021]

Changed your filter recently?

[Eric]

Make sure you haven't used regular fuel hose to connect the pump to the outlet (the small piece of hose that sits inside the tank)..
Regular fuel hose is not suitable for use inside a fueltank and will rupture or 'balloon' when under pressure...ALWAYS use the special type fuel
hose that is suitable for use inside the tank. (this type of hose costs 4-5 times as much as regular hose)

Also, measure voltage at (or going to) the pump...it should be around 14 Volt at full boost.

another test is to bypass the fuelfilter to see if it makes any difference in fuelpressure