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  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech

CFI - two fuel pumps into one?

  • Thread starter Thread starter Darkwriter77
  • Start date Start date Aug 17, 2008

Darkwriter77

Resident Ranting Negative Nancy
5 Year Member
Jul 1, 2005
314
281
134
Apache Junction, AZ
Aug 17, 2008
#1
  • Aug 17, 2008
  • #1
Sooooo, for the time being, until I can scrape together the funding for a full CFI-to-carb conversion (gonna be awhile, it seems) and beside the fact that I'm not sure if I could squeak through emissions with a carb'ed setup, I'd like to at least convert my exhaust from singles to duals. Small problem: I have two fuel pumps, and the high-pressure pump and the fuel filter are both mounted right where the passenger-side muffler need to go.

I remember reading somewhere that in '85 some of the CFI cars switched to the same single-pump setup that Ford used on '86+ EFI 5.0's, and that that '84 and early '85 CFI two-pump setup was just a temporary setup they had been using in the LTD II's and early Mark VII's, as well... And being that the operating range of fuel pressure is pretty much the same between CFI and EFI motors, I got to thinkin'... (and smoke started rolling out of my ears ).

Sooooo ... being that CFI uses a low-pressure in-tank pump and a high-pressure external pump, would I be able to get away with just switching out the stock tank for an '86-'93 tank with just one fuel pump (the in-tank high-pressure pump) so I can delete the external pump and relocate the filter up closer to the tank where it's supposed to be? I can score a used pump, tank, and sending unit altogether for $25 locally, and if the swap would work, I would later on be able to just drop the tank, remove the high-pressure pump, and poke in the older low-pressure pump if/when I get around to converting to carb.

Anyone done this before? ... or does anyone know if the single high-pressure pump would work in place of the low-high two-pump setup?

Also, will the sending unit for a later-model ('86+) 5.0 hook right up or at least can be wired up to work with the '84? ... or will I be losing the functionality of my fuel level gauge?
 

Darkwriter77

Resident Ranting Negative Nancy
5 Year Member
Jul 1, 2005
314
281
134
Apache Junction, AZ
Aug 18, 2008
#2
  • Aug 18, 2008
  • #2
Bump.

Anyone?
 

BK_CAULEY

it's built for speed not longevity, woman
Dec 26, 2006
0
10
49
Thomasville, ga
Aug 18, 2008
#3
  • Aug 18, 2008
  • #3
i dont see why it wouldnt work. the only things you hve to make sure of is getting proper power to the pump and rgulating pressure if its higher on 86+ cars.
 

Darkwriter77

Resident Ranting Negative Nancy
5 Year Member
Jul 1, 2005
314
281
134
Apache Junction, AZ
Aug 18, 2008
#4
  • Aug 18, 2008
  • #4
Well, if the pressure is higher, it shouldn't affect it because the CFI has a fuel pressure regulator right there on the throttle body assembly, as well as a return line - everything excess just gets sent back to the tank. I guess maybe the bigger questions would be whether or not the fuel level sender is a direct hookup (or at least can be spliced on) to work with the '84 dash/fuel level gauge, or if I'd be losing out on that? ... and will I need to buy all-new fuel line from front to back or can I just get some connectors to fit things together when I get rid of the external pump and move the filter back up above the axle near the tank?
 

Darkwriter77

Resident Ranting Negative Nancy
5 Year Member
Jul 1, 2005
314
281
134
Apache Junction, AZ
Aug 19, 2008
#5
  • Aug 19, 2008
  • #5
Bump.


Man ... everything on this car must be a mystery.
 

Darkwriter77

Resident Ranting Negative Nancy
5 Year Member
Jul 1, 2005
314
281
134
Apache Junction, AZ
Aug 20, 2008
#6
  • Aug 20, 2008
  • #6
Nobody?
 
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