Hi guys, I recently finished building my engine for my 2003 silverado rcsb.

5.3 bored to 5.7
cam SUM 8710R1
heads 243 ported and milled
long tube headers
injectors 12613412 (lab tested)
wideband innovate MTXL-PRO

I decided to go with a tune in speed density and open loop, I started marking my VE board but by the time I went WOT my fuel pressure dropped to 20 psi below 3200 revs I came to the conclusion that I would go for a bigger fuel pump, I bought a walbro 255 (I also changed my fuel filter). I installed the new fuel pump and started driving with a quarter tank of fuel, I decided to go wot and the exact same thing happened but now at a little higher revs I also saw that when I came to a complete stop and accelerated to continue the engine had no power to push and was shuddering.
No dtcs for now

Any ideas?

 

What injectors are you running?

 

Brand new set of 8 Delphi 50lb/hr fuel injectors, part number 12613412.

 

Was the injector data adjusted in the tune?

I wonder if the Fuel pressure regulator has an issue?

Also try filling up to 1/2 tank and make sure it's not just sucking the bocket dry under acceleration.

 

Yes, injector data adjusted for vacumm regulator, fuel pressure regulator works fine, i will try to fill up to 1/2 gas tank, you have some tips to prevent my inner bucket from running out of gas? when in put the new one fuel pump i didnt insntall the bucket soak i just put the soak from the fuel pump ¿that can cause issues?

 

I don't know if the sock missing can cause issues. I have never tested with out one.

But with only 1/4 tank, it is possible that when you accelerate all the fuel is moving rear ward uncovering the pick up and it is possible that maybe it sucking the bucket dry before the fluid levels out and can be picked up again by the pump. I know Some people move to returnless style tank to get a larger bucket for the larger pump's. But I have never done any testing.

If the issue goes away with 1/2 tank of fuel, you will know you have a fuel supply issue.

I have seen vehicles stall out while going around a corner with a 1/4 tank or less of gas. We discovered the pick up of the pump was being uncovered due to the way it was mounted in the tank. So when you went around like a right hand corner, It would suck air and drop pressure causing the engine to stall out.

The other issue is tanks in modern cars are plastic. Over time due to weight, heating and cooling as well as pressure, they tank will sag in the center. The more it sags the further the pick up of the pump is from the bottom on some models.

 

It makes sense, when I accelerate the gasoline moves from one side to the other, thank you very much for your time I had forgotten how kind the community is in this forum, when I have results I will return

 

I’m back, the solution was to have 1/2 tank of gas and put the filter sock outside the bucket, now i will drive with 3/4 of gas if i want hit hard the gas pedal, thanks dude

 

Cool. Thanks for the update.

 

Is this the kind of problem that will be SOLVED by a Holley HydraMat fuel intake sock ?