Which pre filter with external fuel pumps?
Thread Starter
TECH Fanatic
iTrader: (2)
Joined: Feb 2003
Posts: 1,011
Likes: 4
From: Corpus Christi, Texas
Which pre filter with external fuel pumps? I can't remember what pre filter to use with an external pump.
I guess something cheap but will work.
Needing 3/8" inlets as it's a 255 pump and I'll use regular hoses on the upstream side of the pump.
Someone said at one time the parts stores may carry them.
Also do we really need to run a post filter or after the pump?
I guess something cheap but will work.
Needing 3/8" inlets as it's a 255 pump and I'll use regular hoses on the upstream side of the pump.
Someone said at one time the parts stores may carry them.
Also do we really need to run a post filter or after the pump?
TECH Senior Member
Joined: Jun 2016
Posts: 22,291
Likes: 3,615
From: Central Cal.
You DO need to run a post-pump filter to protect the injectors, which are more sensitive than the pump to fuel crud. A 10-micron unit will do it. Mounting the filters immediately pre- and post-pump is the easiest to do from a servicing and installation viewpoint.
9 Second Club
Joined: Nov 2003
Posts: 13,616
Likes: 185
From: Norn Iron
What filter size...will depend on the injectors used, but for pre-pump 40-100micron will be fine when correctly sized.
Some injectors are fussy as ****, others not so. ID are very fussy, Siemens less so. If you can get 10 microns or lower post pump, then that should cover most injectors.
And for any pre-filter, ensure it has adequate flow ability given you're relying on gravity. EFI pumps do not suck, nor do they like to try and suck so using a small filter like the Earls one above is not a good idea even if some get away with it.
Bigger is most definitely better here given the volumes of fuel that will pass through it
Some injectors are fussy as ****, others not so. ID are very fussy, Siemens less so. If you can get 10 microns or lower post pump, then that should cover most injectors.
And for any pre-filter, ensure it has adequate flow ability given you're relying on gravity. EFI pumps do not suck, nor do they like to try and suck so using a small filter like the Earls one above is not a good idea even if some get away with it.
Bigger is most definitely better here given the volumes of fuel that will pass through it
