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.

[Mangled03gmc]

Ok so you have a intank walbro, one inline?? That is kinda unclear.. If the one inline is going south that might be the problem, remove it, see what happens. As the inline can draw through another pump, but one can't push through a weak or dead one.. If you decide to do a intank, save alot of hassle imo and do a single BOSCH 044.. Here is a write up I did when I did mine.. Have about 270 buks in it, you might have a lil more if you decide to get factory connectors..


http://www.performancetrucks.net/for...d.php?t=428535

[sliverado rst]

wow man i thought everybody was running 1intank and 1 inline pump, i guess i was wrong, ill have to see if i can bypass it hopefully without replacing a line, thanks for the link.