water separator/fuel pump plumbing?

[kapnklug]

So I'm adding a Racor heated fuel filter/water separator. I've heard that for the water separator to work, it has to be on the "suction" side of the fuel pump, not having the fuel pushed through it. Problem is, I'm already running a Walbro FRB-22 electric fuel pump, mounted with a small pre-filter on the frame rail near the tank. There's no room there for the 16" tall water separator, it has to go in the engine compartment. Will the water separator still work if it's downstream from the pump? Or, will the fuel pump still work OK if I remount it in the engine compartment downstream with the water separator? The pump supposedly has a check valve in it to prevent losing its prime, but if I ever have to drain the line between the tank and the pump, I'm not sure the pump can prime itself over such a long distance.

 

[3dubs]

The fuel pump can prime itself just fine. Without looking I believe it is a solid line to the fuel pump. There is a small rubber section under the body of the truck you could tap into.

The stock fuel filter is heated and has a water separator. it drains out the bottom. To top it off there is a light that comes on to tell you when to drain the water. Unless you are making bio-diesel or leave the filler cap off the stock filter does a great job. I add sulfur to my fuel and it got wet. The stock filter separated the water. The light came on and I just opened the drain. You can spend the money if you want. But I drive my truck everyday and like to keep it simple.

 

[kapnklug]

Hmmm, but the stock filter on the firewall is AFTER the stock (mechanical) fuel pump. If there's a water separator in there, it is not on the suction side of the pump. I was under the impression that a water separator will only work when it is on the suction side, not the pressure side, of the fuel pump???

 

[watkinssr]

Hmmm, but the stock filter on the firewall is AFTER the stock (mechanical) fuel pump. If there's a water separator in there, it is not on the suction side of the pump. I was under the impression that a water separator will only work when it is on the suction side, not the pressure side, of the fuel pump???

I'm no expert on these things, but apparently that's not the case.