60lb injectors, low fuel pressure

[sliverado rst]

ive been after a low fuel pressure/ lean issue for a while now, i used to only have a about 38lbs of pressure at an idle, and then when the truck started making boost (magnacharger) my pressure would drop way down and the truck would run lean. so i upgraded to 60lb injectors, gutted out the stock sending unit and put a walbro 255 pump in the tank witch brings me to around 48 psi, then i disconnected the fuel pressure regulator and brought me around 52-54psi at an idle, but when i start making boost im almost down at 20psi, and the things kinda of slug. so im thinking i need to change my in line pump, im not sure witch pump it is its the one that comes from mangacharger, i just don't know what i should run for an inline pump to feed those injectors. any suggestions?

[Atomic]

Might want to upgrade the wiring to the pump. I have a walbro 255 in take and 60lb injectors and have around 50 at idle and cruise, but down to about 45 at high rpm WOT.

[oleshifty]

honestly, get rid of the 'magnacharger' pump, and have the computer tuned for charger/injectors.


Depending on boost, you may want a dual 255 setup in tank, I would avoid an 'inline' setup.

[sliverado rst]

well i currently have a nelson tune, and Ive never seen a dual in tank pump setup for a truck, do you have to make it?

[oleshifty]

ya, several guys here are running them. Sure someone has a pic / howto laying around

[Mangled03gmc]

What kinda power are you making?? I agree, check all the wires to and from the pump.A faulty or loose connection will def drop amp/volts.. Hook or put a new FPR back on the truck. Then make sure the tune is spot on for the size injectors that you are using. A 255 pump is good to 500 whp.. Their is a guy making like 800 hp using a single 255, it is keeping up fine

[danger_ranger83]

http://www.ls1tech.com/forums/fuelin...l#post13504876

[sliverado rst]

well the pump that's in the tank now is spliced into the factory pump/sender unit were it was originally, and it still uses the factory harness that it did before and it did have power when i installed it, however i think when the old pump in the tank was weak it may have been straining my inline pump, my inline pump i can still here it when i the turn the key and it primes itself, but it really don't sound very good.