I had pretty much the same problem at one time... My fp would raise with boost to a certain point. I was told by the previous owner that I had a high volume fuel pump but when I had the tank dropped it turned out to be something like like a 190lp or something I can't remember but it wasn't a authentic walbro 255 hi volume one
How much fuel in the tank when this happens ? If it under 1/3 then its starving for fuel due to the fuel runs to the back of your tank (poor baffles) in the tank, uncovering your pump. Lowering your truck makes this worse..
bad fuelpump:rant: new one fixed it right up:tup:Did this ever get resolved? Just curious...
(There is a FP test connector at the firewall near the dist. in case you didn't know.)
put the feed line from the fuel rail in a bucket and measure the volume over a specific time. i don't remember the specs for our trucks though. what size of injectors are you running?
Also you can amp draw the fuel pump. The less amp's the pump draw's it's junk. 6amp's or less it's junk.just my :2cents:
Failing pumps can also draw too much current. The harder a pump has to work, the more amps it's going to draw.