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Fuel Pump F134 Problem

Discussion in 'Early CJ5 and CJ6 Tech' started by PierreDnepr, May 22, 2021.

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  1. May 22, 2021
    PierreDnepr

    PierreDnepr Member

    Barrie Ontario
    Joined:
    Sep 4, 2013
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    Hi,

    Last year my mechanical fuel pump quit on me... it was giving me trouble for awhile when the weather was really hot and driving in town. It was sputtering and showing sign of fuel starvation especially on hills. One day it quit and after diagnostic and a tow I had to order and new one and replace it.

    Since the jeep in fully stock except for the Solex carb, I ordered the same mechanical pump with the vacuum booster for the wipers. Well that one is starting to give me the same telltale sign as my old one before it quit. Yesterday it was starving with fuel (+30C in traffic). The fuel filter was almost empty. The pump is made by Omix Ada. My old one had a proud "Made in the USA" stamped on it and it does look old.

    My question is... because of the Solex, I added a fuel pressure regulator. so my set-up is:

    Fuel tank -> steel line to the front -> rubber line across -> pump -> rubber line -> pressure regulator set to 3 psi mounted on the fender -> fuel filter attached to the regulator -> rubber line across to the engine -> steel line along the engine -> Solex carburetor.

    Is it possible that the fuel pressure regulator is screwing something in the pump? may be because of backpressure? I wonder because its a new pump and to have it quit that early is surprising (although it is Omix Ada?). Should I ditch the fuel pressure regulator?

    Last question - if I have to change it again, do you know of a store that retails American made pump that are reliable? or should I considered re-building my old one.

    Thanks a lot for any information... I haven't been on the site for a while... the Jeep was not giving me too much trouble and I was too busy with work... I am now semi-retired so the CJ-5 will become a new hobby.
     
  2. May 22, 2021
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Hills of NH
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    Before anything else, I would want to be absolutely sure the fuel line, tank intake, and any or all filters, are completely clean. And that the tank is venting (try loosening the cap...).

    I had the similar starvation problem, which I eventually tracked to my filter being clogged - even though it looked clean.
     
  3. May 22, 2021
    Primer Coat

    Primer Coat New Member

    Ohio
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    Jul 17, 2017
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    Ditto That. In the spring after it sits all winter I have have that very same problem. CJ5 would run for several miles and then act fuel starved and just quit. Every spring a new fuel filter and problem solved.
     
  4. May 23, 2021
    PierreDnepr

    PierreDnepr Member

    Barrie Ontario
    Joined:
    Sep 4, 2013
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    Hi,

    Yesterday I looked more closely at the set-up. The jeep was cold and the fuel filter filled up nicely but then I notice the rubber hose from the steel line across to the pump spraying some fuel. It looked like a B-movie horror scene, so at the moment I'm assuming that when it get hot the old rubber just collapsed or is internally compromise. We are still in a stay at home order in Ontario so the stores are closed... I ordered a new hose on Amazon. Will let you know how that goes...
     
  5. May 28, 2021
    Oldpappy

    Oldpappy A.C. Fults - Curmudgeon at large 2022 Sponsor

    East Tennessee
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    I assume you mean the standard flex hose from the steel line coming from the tank to the fuel pump inlet. If that hose is leaking it would certainly limit the volume coming out of the pump, so very likely is your culprit. Be sure to replace that with a good quality flex line, with brass fittings, made for the purpose rather than just clamping on some rubber fuel line.

    If you do indeed determine you have a bad fuel pump I recommend rebuilding the old pump rather than buying something from Omix-ADA, but be aware there are cheap kits, and good kits which are not so cheap. You want to be sure to get a kit with a diaphragm designed to handle the ethanol gasoline, and the cheap kits I have looked at do not mention this, so I assume that is one reason they are cheaper.
     
  6. May 31, 2021
    PierreDnepr

    PierreDnepr Member

    Barrie Ontario
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    Thank you for your advice "oldpappy". I had a rubber line with clamps and it was really bad on the inside... its currently replaced with a new rubber line but I will take your advice and switch it to a real flex line... the last ting I need is a fire in there.
     
  7. May 31, 2021
    Oldpappy

    Oldpappy A.C. Fults - Curmudgeon at large 2022 Sponsor

    East Tennessee
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    One of the first things I do when I get an old Jeep is renew the fuel system.

    I have never bought a running Jeep, and most of the Jeeps I have brought home had sat for many years, so this usually includes a new tank, and always includes a new hard line from the tank, a new flex line to the pump, a rebuild or replacement of the pump, a new line to the carburetor and a quality fuel filter.

    Of course this would depend on the condition, and if some of those components looked fairly fresh I would use them, but I have never bought one that was in any way "fresh".
     
    Fireball likes this.
  8. Feb 20, 2022
    Eric

    Eric Member

    CA
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    More deep research and who do I find?!?!? hahahaha.
    Your advice in another thread was very helpful and now I am finding more help! The copper fuel line I mentioned in the other thread went directly to the fuel pump and now I see I am missing the flex line. I can see why, when several people mention copper becoming work hardened, there is a flex line. Well... back to the drawing board! Thanks again.
     
  9. Feb 20, 2022
    Oldpappy

    Oldpappy A.C. Fults - Curmudgeon at large 2022 Sponsor

    East Tennessee
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    I like to talk about this stuff. The problem on an internet forum is there are often a lot of well meaning people wanting to be helpful who end up giving bad advice. Sometimes dangerous advice.

    I am not always correct, and am happy when someone tells me when I am wrong, but I have worked on a lot of old cars over the years and know a few things.

    When I said "flex line" I am talking about a proper line with fittings not simply a rubber fuel line with hose clamps which a lot of people use. A rubber hose clamped to the steel lines can leak air even if it doesn't leak fuel.
     
    scoutpilot and Eric like this.
  10. Feb 20, 2022
    Eric

    Eric Member

    CA
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    I should have done this weeks ago: On my 1963, the stock fuel line is in place. The jeep is next in line after my 1962 (the one with all the issues). In all the MBs, 2As, CJ7s, etc. that have come and gone, I never tackled the fuel line so it was all "new to me." The '63 is dusty and difficult to get to, but I braved it today and discovered the steel fuel line from tank to fender, the flexible line (with fittings at each end) from the first line to the pump, then the steel line from pump to carb. I see the dangers the PO left me with and appreciate all the advice from you and others who, quite possibly, saved my *** if this line failed. I can see one immediate weak spot where the copper line attaches to pump... loose and potentially a site for separation. I will tidy that up immediately.

    I'm still leaning strongly toward bending my own nicopp line from tank to fender and installing an inline filter there. Is a threaded one more likely to last than one that requires rubber fuel lines and hose clamps? (I am guessing that the response will be yes.) I read elsewhere that you like ceramic ones closer to the carb. I do not believe I have the skills to do that so will likely attach one to the line just before the pump somewhere. Perhaps you, or anyone, has recommendations for ad decent, not overly expensive, inline fuel filter? Thanks.
     
    Last edited: Mar 2, 2022
  11. Feb 20, 2022
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Hills of NH
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  12. Feb 20, 2022
    Eric

    Eric Member

    CA
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  13. Feb 20, 2022
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Hills of NH
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    It looks that way. You'll have to figure it out, but you could surely adapt whatever hard fittings you choose.
     
    Eric likes this.
  14. Jan 2, 2023
    Dwins1

    Dwins1 Member

    Port Richey, Florida
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  15. Jan 2, 2023
    Oldpappy

    Oldpappy A.C. Fults - Curmudgeon at large 2022 Sponsor

    East Tennessee
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    I have used those too, one is on my CJ5 now. They are just fine, but I usually look for a AC or Carter glass bowl filter. I prefer the Carter with ceramic element because they last forever, the element gets dirty you just soak it in solvent and put it back in.

    If the filter isn't filling all the way that usually indicates an air leak in the plumbing.

    Here is a AC filter, with a replaceable paper element, which is on my CJ2A. I have a NOS ceramic element Carter I plan to put on my CJ5 to replace the throw away inline filter on it now.

     
    Last edited: Jan 2, 2023
    Dwins1 likes this.
  16. Jan 2, 2023
    Dwins1

    Dwins1 Member

    Port Richey, Florida
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    I’m up in Maryville this week.
     
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