chighley_00

I installed a walbro 392 fuel pump and new 3/8 line from the tank to the pump and 3/8 to the stock fuel filter. I am using a SimFlo Bypass Regulator after the pump. My fuel pressure is 21 at idle 19 at 60 mph. Then when I turn the edge juice on 5 it will drop the pressure to 10 psi. Is this a good number or do you think I should do something different?

sid325

My FP idles at 22, normal driving about 20 and running hard about 18. That is with my Smarty on level 9, never dropped below 18. I have never seen my FP drop that much?

Sid

Rpainter

mine only drops about 2 psi from idle to wot.did you put in a prefilter between the tank and pump??

matego

I agree, something doesnt sound right. My fuel pressure is 29 @ idle and drops to 26 with the Edge on 5. That is with 3/8 line all the way from the filters.

vzdude

I have 3/8 line from the tank, thru Walbro, to the factory filter. From there, it goes to 1/2" lines and thru a 2 mic filter. I see 20psi @ idle and @ 60 mph. With quad race on highest level @ WOT I can draw it down to 15-16 psi.

chighley_00

I bought a dorman fitting to go right on the tank since I have an 04 with no lift pump in tank. Then from their went about 2 foot and put a prefilter then another 2.5 foot and hook to the pump. After the pump I went 4 inches and put my SimFlo Bypass Regulator. From there I went to the adaptor block I bought on the stock fuel filter. Then I used a piece that was 4 foot for my return line. I plumed my return line in the old breather line since I did the tank vent mod.

doug60

1/2 pick up tube / 392 pump with a 18 pound check valve.1/2 inch lines all the way to CP3.
3 micron filter a tank / stock filter/ 2 micron before CP3.
19 to 20 at idle & it seems to hold 18 even at 60 pounds of boost.

vzdude

I would guess the trouble with your Walbro setup, and the difference from the rest of us is the bypass regulator. Can't exactly explain why, but it appears that is the only difference. I used GDP's regulator in my setup.

doug60

What size wire & where are you pulling power from. Maybe it not getting enough juice?

chighley_00

I ran 1 30 amp wire from the battery to a fuse then to a relay. Ran a 14 ga wire from the hot lead on old pump for a trigger wire for relay. Then I ran a 14 ga wire for ground on relay. Then from the new pump I ran 14 ga hot lead to the relay. I also ran a ground from the pump to the battery.

doug60

That should do it!

derf464

Well I don't know if this is your problem or not but it's where I would look. I was having pretty much the same problem. Mine was that dang pressure regulator. I just bought a Mallory FP regulator from summit racing part#MAA-4307M. I have it adjusted to 18# and it does's budge but a couple pounds either way, and solved my problem. Hope this helps

trik396

I have 20lbs at idle and 20lbs when I put down 617hp. I use an Aeromotive bypass regulator. Not cheap, but effective. As others have stated, your bypass reg is suspect only because it's the only different piece. A bypass regulator SHOULD keep whatever pressure you set it at, all the time, especially with the Walbro392. You shouldn't be losing any pressure with the correct type of bypass regulator.
Glacier uses a "check valve" type regulator which is totally different and pressure WILL change.

vzdude

Agreed! If (and when!) I start laying down some more serious HP, I plan on changing to the Aeromotive type regulator. GDP's just fit in the budget and time constraints I was under at the time of my install!

trik396

Nothing wrong with a GDP style checkvalve. It'll get the job done. In the constraints of a "kit" type setup, it is somewhat easier to install and costs much less money.

In a no compromise system, you have to spend more money, but it's generally worth it in the long run.