Trever1t, I also have the walbro 340 pump. How much boost are you running? I wonder why I'm running lean and you did not?

 

Tuning? I have the advantage of one of the nations most respected GM tuner's shop only minutes from home. We have repeatedly tweaked the fueling on the dyno and the street. I also run Methanol which is added octane fuel so that helped too.

 

I recall that someone on here with that style of intank FPR turned the screw and said they got a couple of more psi out of it.

I have run my setup with 8-12+ psi. Just running a 3.2 pulley(8-10 psi) until I get the fuel pump fixed. I feel that, on your motor, with a returnless fuel system, the 42lb/hr injectors will be pretty well maxed out at 8 psi/upper RPM range. Mototron 60's(actully 68's at 60 psi) will be able to provide the required fueling at the lower fuel pressures.

There is also an Aeromotive inline booster pump controller("Digital FMU") available for returnless systems. This allows you to add an inline booster pump without requiring a return line. Best price I have seen so far is $420
http://www.aeromotiveinc.com/product...tsub=0&prod=32

 

A couple more thoughts:

What are your shift points? Setting lower shift points will keep the RPMs down and reduce fuel requirements.

A methanol injection setup will provide some extra fueling.

 

DrX, Shift at 5600rpm, Do you think the Aeromotive unit would be better than the Magnavolt? I drive the truck alot, so I would like to stay away from meth if possible. I would think I would be always having to fill it.

 

I use less than 5 gallons in 3 months. 1 pass at the track is ~a cup. It only comes on at 3lbs and I can stay out of boost and still be faster than most traffic all day.

 

So you don't really want to lower your shift points any more to compensate.

Not sure if adding an inline pump will be that much better than boosting the voltage to the single 255 you already have unless you add an even higher flowing pump($). Max flow will always be a little higher than that of the higher flowing pump in the series. If both pumps were 255's, then you might be better off with just a voltage booster. Unless the Aeromotive unit also allows you to to control the voltage to the second pump.

Either way the intank pump still needs to be working properly.

I know someone on here has used the Aeromotive unit, just don't recall who.

 

Anyone else?

 

O.K. the latest update. I replaced the FPR and removed the factory fuel filter. When I put another FPR in, I turned the screw a little. Now the fuel pressure starts at 62lbs, but still drops to 53-54lbs. There is nothing else but fuel lines and the injectors. What's going on?

 

Are you referring to the filter and FPR that are inside the tank?