When my truck drops below half a tank on fuel it loses prim...and I have to get out, pump the hand pump, and it starts right back up...but if I remove power from my fass 150 lift pump it doesn't act like anything is wrong..Thanks for any help and I hope this is simple..So how can I use my pump without problems?

Moved to Fuel upgrades.

I know I have seen this problem before but I can't recall off the top of my head what it took to fix it. Did you try doing a search? I would do it for ya, but my bandwidth sucks out here! LOL

Does your pump return bypass fuel via the filler neck?

I heard from somewhere that the tank "cup" is not refilling fast enough and I need a suck tube or re-route the return ...but how?

Ill copy and paste my post off Comp-D since this more of a target audience here:

The issue is your stock sending unit.

Here is what happens:

The FASS is a recirculating fuel systems. Meaning its moving fuel pump volume all the time. Your stock sending unit stays full with fuel for the FASS to pull from when the tank is full or above 1/2 tank. BUT once the fuel level drops below the top of the fuel "Cup" in the tank, the FASS pulls more fuel out than what the "Cup" can allow back in to fill up. SO the cup empties and the FASS sucks air. The "Cup" fills back up and the whole song and dance happens again.

This prob is a hit an miss one with the D-Max trucks...some work fine and others kick and scream.

Fix's:

1. Suction tube kit. Install one and you will get more use our of your tank.

2. Route the FASS return into the stock fuel "Cup" or "Basket". This will increase the refresh rate and replace what the FASS is taking out due to circulation.

It real simple....you either install a Stuction tube kit, which any FASS dealer can help you wiht (Part number STK-1001). This will let you use more of your tank.

OR take the FASS return line, and figure out a way to dump the return back into the sending unit via a bulk head fitting or something to that nature.

so the suction tube kit will help the 1/4 tank problem ?