150 Fass problem

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 it doesn't act like anything is wrong..Thanks for any help and I hope this is simple..

DuramaxDaddy29 said:

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 it doesn't act like anything is wrong..Thanks for any help and I hope this is simple..

Click to expand...

It is...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.