New here, I just bought a 2004 Denali XL with a Joe Gibbs Radix supercharger, and it has some fuel issues, the PO said it had gotten hard to start so he replaced the walbro 255 with a new one, but the problem is still there, it looses its residual pressure in the rails after sitting for a few minutes. I dropped the tank today and it has a walbro GSS340 in it, which has the big center inlet pick up, but It needs the side pick up (342)?? not sure if this is the issue. Also with a full tank the thing runs great, at 1/4 it acts like its running out of fuel, and actually stalled a few times. Any help would be great!

Here is a pic of the basket that it has, anyone know if the check ball under the grey cover keeps the pressure in the line or is it something in the pump??





and here is what the beast looks like:

 

Nice ride!! I think the check valve is in the outlet nipple. I also think you have the correct pump, but the placement pf the pickup shouldn't cause you problems. You might try e-mailing Racetronics, or call Lonnie's. They're both sponsors on Ls1tech. You might need to replace the corrugated hose with a new one, and get the proper clamps. Might not be making a good seal to the outlet nipple. Racetronics has all the proper stuff to get the job done.

 

As Wkdivr said, sounds like your pressure is bleeding off once you shut it down. You want crimp clamps for the hose, worm gear clamps have a tendency to work loose on the fuel pump. New hose and clamps will be cheap.

 

I just talked to magnuson and it is the wrong pump should be a gss341, does anyone know where the pressure regulator is on this pump housing?

 

It looks like the grey thing on the left?

 

That is a filter, but there is a small ball and seat device on the side that looks like it could be a pressure relief.

 

AH! i forgot they had the filters in the tank.

 

On the set-up you have, does the plastic line go straight from the pump to the grey canister? Because, on mine (04 GMC Sierra) , the line from the pump goes to the far side of the canister/filter; fills the filter up; then there's a plastic T fitting that has the regulator on it, like a side fitting. The fuel then comes out the top of that fitting, to the top of the fuel module. The regulator then shoots the extra fuel into the venturi; which helps keep the bucket full. Looks like somebody removed the regulator altogether. On the driver's side of the fuel rail, up on the engine, there should now be a fuel block, with regulator that has 2 lines attached. Hopefully a supply, and return line. A picture would be helpful. Is yours drive by wire, or cable?

 

It is by wire, and there is no reg. On the fuel rail, is the regulator the stainless gizmo onthe top of the filter with a ball and seat, held down by a spring tab, and covered by a piece of grey plastic with two clips on it?

 

You can see it in the first pic.
It also has a small black plastic ring under the ball, but I'm not sure if it needs to be between the ball and seat, or the ball and the spring.