ok guys, i have not seen any eve guys running these. but a little background on my issue:

I'm fully build, ams fuel system, -8 feed, factory fuel feed as a return. i have a 255 and a 400 in tank "now"

the problem i am having is fuel pressure as soon as i get into boost jumps big time, from low 30 to high 90+. now no where into the tune I'm going lean at all. just my tuner does not like that view of it going all over the place. i have checked and done everything i can as so make better lines, swapped fuel regulators, fuel press sensors, and still same thing. its too much fluctuations in the graph.

now my tuner has recommended me this part:
https://www.injector.com/cart/pc/vie...H&idCategory=4

i mean I'm going to try it, but i would like anyone to try and comment on my issue. i have rewired the factory harness and the other in tank on relays, so they are seeing almost 14v all the time, and still the same thing. I'm running 2200 ID injectors just incase. and a aem ems V2.

 

The Walbro E85 is a beast. I see a pressure spike when mine switches from low to full voltage. Not surprised that you're seeing a pressure spike when switching it on while a 255 is already going full bore. You're gonna need to install a -6 AN return and probably raise the boost where it engages to 15-20 psi depending on your power level.

 

but bro, it not a spike. its like pressure becomes all erratic... look you also commented on my thread right here:
https://www.evolutionm.net/forums/ev...ssure-log.html

remember we spoke about upgrading wires and doing a relay on the factory harness, well all that has been done. and still same thing. only thing my tuner can think is erratic pressure, and can maybe be fixed my adding a fuel dampener, will help with the erratic behavior. the crazy thing is the shops car we have the same exact setup and he's not having this issue. and the tuner tunes both our cars. but mine seem to be a freak! so i don't know what else to do. how would i go about doing a -6 return and keeping the siphon effect?

 

Yeah, with the siphon, a -6 AN return will not make much difference. I guess I'm out of suggestions except that you should go through the fuel system piece by piece. Perhaps its something as simple as a bad seal around the pump outlet nozzle, or maybe its a bad pump.