Page 1 of 2 12 LastLast
Results 1 to 15 of 26

Thread: Frame mount fuel pump

  1. #1
    Fuel Injected! dktool's Avatar
    Join Date
    Oct 2016
    Location
    Covina, CA.
    Posts
    102

    Frame mount fuel pump

    Can anyone recommend an inline pump to use for the low pressure tbi ?
    And...will it draw through the existing in tank pump ?

    My reason is to have one plumbed in with valves to use as a "don't leave me stranded" pump.
    My application is a Class A motorhome which makes changing an in tank pump a super b-atch.
    Dean

  2. #2
    LT1 specialist steveo's Avatar
    Join Date
    Aug 2013
    Posts
    4,071
    if you're worried i would entirely remove the in-tank pump and install an external pump and filter then carry a spare (easily swapped on the road)

    the in tank pump has a strainer and check valve that can screw you over

  3. #3
    Fuel Injected! dktool's Avatar
    Join Date
    Oct 2016
    Location
    Covina, CA.
    Posts
    102
    What pump would you recommend ?
    Dean

  4. #4
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    6,411
    Quote Originally Posted by dktool View Post
    What pump would you recommend ?
    The 1988 Ford F-150 / 5.8 Liter used a frame mounted fuel pump and an in-tank fuel pump.

    I like the idea of a "Factory" fuel pump for cost and availability. Aftermarket Ford F-150 fuel pumps are good option, but don't include the isolation mounting like the Motorcraft PF4.

    The picture below is a Motorcraft PF4

    PF4-Ford.jpg

    E7TZ9C407BA-ANG.jpg

  5. #5
    Fuel Injected! dktool's Avatar
    Join Date
    Oct 2016
    Location
    Covina, CA.
    Posts
    102
    So Ford used 2 in series but trying to have the frame pump pull through a non running tank pump would not work ?
    Dean

  6. #6
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    6,411
    Quote Originally Posted by dktool View Post
    So Ford used 2 in series but trying to have the frame pump pull through a non running tank pump would not work ?
    I've never tried an inline pump to pull fuel from a non-running tank pump.

    The Carter P74028 (aftermarket F150 pump) is $43.79 at RockAuto. Perhaps an experiment is needed to figure out if installing an inline pump will pull fuel from a non-running tank pump?

    I think everyone understands trying to save time and money. Sometimes simple / low-cost fixes are an option and sometimes simple / low-cost fixes are not an option.

    I've used the F150 pump on several TBI conversions for older GM carburetor vehicles, it's a good frame mounted fuel pump option.

    P74028_P04_KIT.jpg

  7. #7
    Fuel Injected! dktool's Avatar
    Join Date
    Oct 2016
    Location
    Covina, CA.
    Posts
    102
    When you used that pump on a carb did you need a regulator to keep it from pushing the needle open ?
    I have used inline pumps for carbs but they were 4-5 psi.

    I think one for a tbi would need to be at least 20 to over come resistance and let the oem regulator return some fuel to tank.
    Dean

  8. #8
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    6,411
    I’ve only used the F150 frame mounted fuel pump for TBI conversions. The TBI throttle body has a pressure regulator in the throttle body.

    I agree that the F150 frame mounted fuel pump would require a pressure regulator for a carburetor.

  9. #9
    Fuel Injected! dktool's Avatar
    Join Date
    Oct 2016
    Location
    Covina, CA.
    Posts
    102
    OK, so the f150 pump pressure is high enough to satisfy the 12lb'ish tbi ?
    Dean

  10. #10
    Fuel Injected! dktool's Avatar
    Join Date
    Oct 2016
    Location
    Covina, CA.
    Posts
    102
    I was searching for pressure specs for the Carter pump and found it is 43 psi. Excessive ?
    Dean

  11. #11
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    6,411
    Quote Originally Posted by dktool View Post
    I was searching for pressure specs for the Carter pump and found it is 43 psi. Excessive ?
    No, not excessive pressure. The fuel pressure regulator is in the TBI Throttle Body, not the fuel pump.

  12. #12
    LT1 specialist steveo's Avatar
    Join Date
    Aug 2013
    Posts
    4,071
    most pumps only pump fuel, doesn't really define how much pressure you get. a restriction creates pressure. in a fuel system that restriction is generally the fuel pressure regulator (a variable restriction, it starts dumping fuel into a return line as pressure approaches its set pressure). this is just like a thermostat, it starts opening as it approaches its set temperature. a pump capable of pressurizing a rail to 43psi with a 5psi regulator would make only 5psi, just like if you ran the pump into open air, it'd make no pressure at all. that is, unless it flows so much fuel that the regulator or other plumbing becomes a restriction even when fully open -- this is the danger in having 'too much pump'. if you put a ginormous pump into a low pressure regulator it's possible it will create higher pressure than the regulator is set for. this is rare

  13. #13
    Fuel Injected! dktool's Avatar
    Join Date
    Oct 2016
    Location
    Covina, CA.
    Posts
    102
    Long ago I modified the regulator in the tb to make it adjustable but never had enough pump to see any line pressure increase.

    I will try this pump as an experiment to see if it will draw through a non running in-tank pump.
    Last edited by dktool; 1 Week Ago at 09:57 AM.
    Dean

  14. #14
    Fuel Injected!
    Join Date
    Feb 2013
    Location
    DFW, TX
    Posts
    2,353
    The Ford trucks and vans relied on an in-tank pump to feed the frame mounted pump. The only way I had good results with one years ago was to feed it with the mechanical pump. The Ford pump is not good at pulling fuel on its own.

    In-tank pump failure is extremely rare without other symptoms showing up prior.
    Last edited by Fast355; 1 Week Ago at 05:29 AM.

  15. #15
    Administrator
    Join Date
    May 2011
    Location
    Lakes Region, NH
    Age
    55
    Posts
    3,882
    We used aftermarket inline Ford pumps in 97-02 cutaway buses due to the relatively short lives of the in tank pumps. This allowed us to run the in tank pump until it failed completely rather than replace it when it could no longer deliver 55 psi to the injectors. The in tank pump had to be operating for the system to work. The inline pump would not draw fuel through a non-working in-tank pump.

    We would check fuel filters pretty regularly. As the in-tank pump wears, copper from the armature will get captured by the filter. If the filter is drained the copper looks like rust. We would drain the fuel into a clean rag and if it looked like a rusty mess that meant the pump would likely need replacement soon.

    It's possible to use electronics to gauge the condition of the pump. A simple ammeter can give some information. If the current draw is around 2-3A a TBI pump is operating in normal range. An oscilloscope will tell you even more. A failing or "tired" pump will show an uneven pattern as the pump operates. The more the pump wears the less even the pattern.

    For many, many years I fought GM pumps. Dodge and Ford pumps will last for 200k miles while some of the GM pumps would fail in 60k miles. Then I got smart. Turns out you can install a Ford in-tank pump in a GM vehicle. Two of my own vehicles are now using Ford pumps and the results have been good. Parts stores list a pump only (no sender) for a 2000 Navigator. Make sure it comes with the electrical connector. For the pickup sock or strainer I usually ask the counter person if I can look at what's in stock and pick one based on appearance so I don't have an application for you.

    Good luck.

Similar Threads

  1. TBI fuel pump, can fuel be drawn thru it unpowered?
    By kilohertz in forum GM EFI Systems
    Replies: 8
    Last Post: 04-14-2021, 08:01 PM
  2. Fuel pump controller
    By srgould41 in forum GM EFI Systems
    Replies: 6
    Last Post: 05-08-2019, 08:10 PM
  3. Fuel Pump Recommendations
    By dktool in forum GM EFI Systems
    Replies: 2
    Last Post: 05-23-2018, 09:21 PM
  4. Too big of a fuel pump?
    By trippyjoey in forum GM EFI Systems
    Replies: 7
    Last Post: 07-21-2014, 11:15 PM
  5. Fuel pump troubles
    By mike327 in forum GM EFI Systems
    Replies: 22
    Last Post: 11-12-2012, 05:47 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •