Fuel pump question

[Paccool]

Anyone running a FASS or Waldo pump on their first gen? If so, what is the pressure at idle and does it stay constant at full load. Can I put on a pump, say a waldo, and then a pressure regulator to keep a constant 15 psi pressure to the filter. I have the first gen piston pump installed now, gives about 14 psi at idle but at full load drops to about 5psi.

Please don't turn this into a war zone about which electric pump is best, I just need to know if it will work the way I have asked.

[wannadiesel]

I have a Walbro 391 on my truck, it's wired in with the valet switch. My experience with the piston pump has been the same as yours. My Walbro install runs 18 psi under normal conditions and drops all the way down to 15 psi at WFO in 5th.

Mine is set up like this: There's a 7/16" pickup in the tank that feeds the Walbro. Fuel from the Walbro goes into the dirty side of the filter head through a 1/4" NPT tapped banjo bolt (the piston pump is still fully operational). From the filter, I used 3/8" hose to the VE. The bypass regulator is teed into this hose. Having the regulator after the filter keeps the filter from acting as a false load on the pump and is the secret to having good fuel pressure at full power. The bypass line is teed into the vent hose at the tank.

[Paccool]

So the bypass regulator bleeds off excess pressure? Is there not an inline regulator that will work with out a bypass?

Is yours set up like Dave over on DTR? I saw some info on his but never saw any pressures after he did the install.


EDIT - oh crap, just went over to TDR to see if I could find it and got the answer to my question above! Sorta stepped in a big pile on that one didn't I!

[wannadiesel]

Is yours set up like Dave over on DTR? I saw some info on his but never saw any pressures after he did the install.

By an odd coincidence, it is!

You can't use an inline regulator with a Walbro, it is not designed to be dead ended. You have to use a bypass regulator. It doesn't have to be after the filter (GDP's kits are pre-filter) but if you put the regulator before the filter the Walbro is no better than a FASS.

[NeedMoPower]

I'm running a FASS. See 22 psi at idle and have never seen it drop below 20.

[wannadiesel]

I'm running a FASS. See 22 psi at idle and have never seen it drop below 20.

NMP, are you running a filter on the stock filter head or does the fuel line from the FASS run straight to the VE?

[NeedMoPower]

The filter is in the stock location

[wannadiesel]

What filter are you running to get only 2 psi drop? I see 7 psi on a new filter with mine. 25 psi pre and 18 psi post. This is assuming that your gauge is after the filter, right?

[Paccool]

thanks Dave for the explanationabout the bypass. That makes since about an in line regulator, had not thought about it that way.

I saw your hose plumbing to the pump and that would also make it easier to work on things in that area.

[wannadiesel]

Yes, I was able to shove the pump a little closer to the head, too.