Filter Upsteam or Downstream?

[AKOne]

Question: Is the OEM fuel filter upstream of the lift pump or downstream?

[Alpine36]

Originally Posted by AKOne

Question: Is the OEM fuel filter upstream of the lift pump or downstream?

Ours is downstream of the lift pump in series to the CAPS pump.
It's under pressure when the lift pump runs, under a vacuum always going down the road.

[Ljwt330]

Originally Posted by AKOne

Question: Is the OEM fuel filter upstream of the lift pump or downstream?

If you consider the “stream” as fuel flowing from the tank to the engine, then the fuel passes through the water separator/filter before it reaches the lift pump, therefore that filter is upstream of the lift pump. Common rail engines often have a second filter between the lift pump and injector pump, and that filter would be downstream of the lift pump.

[followingsea]

Originally Posted by Ljwt330

If you consider the “stream” as fuel flowing from the tank to the engine, then the fuel passes through the water separator/filter before it reaches the lift pump, therefore that filter is upstream of the lift pump. Common rail engines often have a second filter between the lift pump and injector pump, and that filter would be downstream of the lift pump.

And some have added a second lift pump close to the tank so both filters are downsteam of at least one pump.

[AKOne]

Discussion with the Cummins folks this morning, my single OEM fuel filter is downstream of the lift pump.

[Ljwt330]

Originally Posted by AKOne

Discussion with the Cummins folks this morning, my single OEM fuel filter is downstream of the lift pump.

Yep, did a quick double-check and the filter is downstream of the lift pump. The remote location of the filter got me confused.