About two weeks ago, my truck just died while going down the highway, no warning or anything. After getting it towed home, I check it out and the lift pump was not pumping fuel, but it was running. I pulled the suction line off and there was no suction. I figured there was an air leak in the suction side of the pump, so I replaced the lines, and for good measure, replaced the lift pump as well with a fass system. (I convinced myself that I really needed it!) After hooking everything up, the pump runs good, but again, no suction! I tried priming but nothing happens. I can't wrap my head around on what is going on. I need to get it fixed within the next day and I have no idea where to look for the problem. I drive a 2002 2500 ram. any help is greatly appreciated!

 

When you say no suction, do you mean that the new pump will not pull fuel from the tank? Or, have do actually done a vacuum test on the suction side of the pump and the pump itself is failing to pull a vacuum?

 

The pump fails to pull fuel from the tank, so I removed the line and dipped it into a jerry can full of fuel and it does not suck. I put my finger over the end of the tube and felt no suction. And I done this with both lift pumps.

 

If the lift pump is running and failing to pull the fuel you either have an internal bypass that needs adjustment on the FASS, or a bad FASS.

Most times when I see this it is that the wiring is not providing power, and the FASS is good but simply not running.

The OEM lift pump runs and does not pump fuel when the internal lift pump bypass valve sticks. That destroys the pump.

 

The pump runs, but are you saying its not getting the proper voltage it requires to operate at full potential? If so, how do I check and fix? How would I go about adjusting the internal bypass? Thanks again for your help. I'm getting a migraine just trying to figure out the problem!

 

If it is running, it should be fine. The documentation that came with the pump should tell you how to set the internal bypass. If it does not have the adjustable bypass, call FASS and get them on the problem. There were some defective pumps sent out some time back, but I would have expected all of those to have been replaced by now.