I have a coarse filter before my two EFI pumps, two High Pressure Filters (one for each pump) after the pumps.  My rationale is that I would prefer to keep junk out of the screens on the fuel injectors should something go amiss with a pump.  If one pump failed in a mode that put debris in the flow, then that pump’s filter should catch it and the other pump can continue to provide fuel (hopefully) to the still clean fuel injectors.  If a pump should fail without a filter between it and the injectors then if debris plugged up the tiny screens in each fuel injector – then having the other pump pumping clean fuel would not help.  My plan is that the coarse filter will likely catch any pump damaging debris before it gets to the pumps. 

 

Damaged pump putting debris into fuel line may be a unlikely scenario.   But if it can happen, it can happen to me.

 

Ed