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Fuel Pump?

Discussion in 'Early CJ5 and CJ6 Tech' started by 60CJ5, Jan 6, 2020.

  1. Feb 17, 2020
    DirtRoad61

    DirtRoad61 Member

    California
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    Jun 9, 2019
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    If the crank could not vent, it would have increased internal block pressure.
     
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  2. Feb 18, 2020
    gpjeep13

    gpjeep13 Member

    PNW
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    Ok I thought so. Could this cause or worsen blue smoke exhaust?

     
  3. Feb 18, 2020
    scoutpilot

    scoutpilot Member

    Asheboro, NC
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    You have discovered why the PCV needs to be functioning correctly. When the crankcase can't breathe, excessive pressures develop which will blow seals, gaskets, etc.. The vacuum end of your pump is part of this system.
     
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  4. Feb 19, 2020
    gpjeep13

    gpjeep13 Member

    PNW
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    I read that the vacuum connection is to improve wiper function and if not using wipers it is not necessary. Is that true? If its only necessary with wipers is there any reason to hook it up?
    I understand the crankcase venting and but I still don't really get what the vacuum portion of the fuel pump does for the PCV system?

    This was posted in another thread by Willys3B
    fuel pump madness

    "The fuel pump is a dual action pump. The upper portion is the fuel pump and the lower portion is the vacuum pump. Sounds like you have that figured out. The vacuum pump is an assist for engine vacuum to operate the windshield wipers. In the stock configuration engine vacuum is taken from a port in the intake manifold below the carburator, a steel vacuum line from that port wraps around the front of the engine to a tee on the pump side of the engine. One side of the tee connects to the vacuum pump and the other connects to a steel bodied PCV valve that is connected to the side valve cover. Without the wipers running the engine vacuum pulls air from the crankcase via the PCV valve and valve cover. Turn the wipers on and the engine vacuum pulls air from the wiper motors to operate them. If you open the throttle quite a bit you loose engine vacuum and the vacuum pump then provides the air suction to operate the wipers.

    Here is a view of the pump from the cj3b page;

    http://www.film.queensu.ca/cj3b/Photos/Tech/Fuel/FuelPump.gif

    Also on the 3b page is good commentary on the PCV system as well as good pictures in the engine re-build write-up by Eric Lawson.

    You will have to figure out why the tubes no longer fit in the vacuum pump body and if they can be fixed as you suggested. Also need to find out how oil has gotten into those lines. I'm not sure, maybe a ruptured diaphragm in the pump or oil through the PCV system. By the way the PCV valve is servicable, it is two pieces and unscrews.

    If you do not have vacuum wipers you can ditch the dual action pump for a single action pump and plug the vacuum line to the pump."
     
    Last edited: Feb 19, 2020
  5. Feb 19, 2020
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Sheboygan
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    :rofl::rofl::rofl:
     
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  6. Feb 19, 2020
    scoutpilot

    scoutpilot Member

    Asheboro, NC
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    The pump was originally designed to operate the wipers and augment the entire vacuum system when accelerating. With electric wipers, the value is the same. Only now it's augmenting the vacuum for the PCV while the motor is accelerating.
     
  7. Feb 19, 2020
    gpjeep13

    gpjeep13 Member

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    Ok that makes sense. Thank you. Wanted to make sure it was doing something when I do hook it up
     
  8. Feb 19, 2020
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    It certainly can't hurt for it to be hooked up.
     
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  9. Feb 19, 2020
    tcfeet

    tcfeet Member

    east of west,...
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    May 30, 2009
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    The "creamy" looking sludge on your dip stick tube is common when your engine sits without running often. You need to get the engine
    up to 180-190 degrees to dry the engine out. Mine did that until I replaced the thermostat with a 190 degree new one.. These old
    engine are prone to condensate inside I suppose..
     
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  10. Jun 1, 2020
    60CJ5

    60CJ5 Member

    Alabama
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    Jan 29, 2003
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    166
    ok, an update. had my son replace the fuel pump over the weekend (just now getting into working on cars) Wife and I took it out for a spin around town and it seemed to be running well. then after 30 minutes it started to stall again. it didint die but i know the feeling (just like running out of gas) ran fine for another 20 minutes then did it again. Same again 15-20 minutes later. This is when the light went off, it only does it after sitting on or going up a good incline. On flat land it runs like a champ but stop on a hill and it will do it in the next minute or two.

    I have replaced the fuel lines and checked that they are as far away from the exhaust as i can get them, replaced fuel filter, rebuilt one carb then replaced the carb (I'm not great with carbs but going through basically 3 of them in this hunt rules out a float issue), checked and rechecked the timing. ALL of this was post it starting to die on me. While it was better (didn't actually die) it is still not right. The only thing left is the fuel tank or fuel pick up. thinking my next step is to drain the tank and pull to to see if there is something there.

    thoughts on something there that would only cause a problem a little after being on an incline?
     
  11. Jun 3, 2020
    Jonbbrew

    Jonbbrew Member

    Paso Robles, CA
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    Not to highjack this thread, ok well maybe, but i have been dealing with pump issues as well for my 198. I have posted the start of my discussion before. The PO had blocked of the mechanical pump location, and added an electric one on the frame near the tanks. Well that started acting up and initially i wanted to have the motor look semi original. Well this past week i just got my engine fired up after a long process of doing little things until they became bigger and bigger things. Once i fired it up i remembered why i wanted to also go original. The electric pump woudl just stop now and again. Not sure if it was over pressure, or over heated, etc. Wiring is all good. But also the new mechanical i added back in, is not pumping at all. Not sure if i have to do something special to get it sucking and pumping, but it would never feed to carb. So thus i used the electrical again and thats when i was reminded how it shuts on and off.

    So now i am wondering for ease right now to just get an electrical. I found original documentation for motor specs for the 198 and it states Fuel Pressure at 1500 RPM idle should be 4-51/4 PSI at carb inlet. At fuel pump (original mechanical) 1/2 PSI higher. So if i did go electrical and mounted it back on the frame near tank i assume i would need more PSI than that. Anyone have knowledge or input on PSI for pump i should look at as well as any certain pumps? Links appreciated! Thanks!
     
  12. Jun 3, 2020
    scoutpilot

    scoutpilot Member

    Asheboro, NC
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    In the original configuration, fuel was propelled by gravity from the tank to the pump. The pump pushes the fuel to the carb. Chose one or the other. Mechanical or electric.
     
  13. Jun 3, 2020
    Jonbbrew

    Jonbbrew Member

    Paso Robles, CA
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    I agree I know I need one of the other right now I’m trying to figure out if I can get my new mechanical to work but also in the meantime I’m thinking I may just bypass it and put a new electrical in for now. So that’s what I really need to know now is any suggestions about electrical box with my PSI requirement.
     
  14. Jun 3, 2020
    scoutpilot

    scoutpilot Member

    Asheboro, NC
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    The PCV system is critical to keeping the motor running for years, not months. A motor with a PCV System that requires auxiliary vacuum needs a double-action pump. I'm not aware of a dual-action electric pump. If you can afford it, fix the problem correctly. The next owner of the Jeep will thank you.
     
  15. Jun 5, 2020
    Jonbbrew

    Jonbbrew Member

    Paso Robles, CA
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    What motor did you use it on. It appears for my 198 requires a 4-5 1/4 PSI at carb @ idle to 1500 RPM. That model only goes to 3 PSI
     
  16. Jun 7, 2020
    DirtRoad61

    DirtRoad61 Member

    California
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    F134
     
  17. Jun 8, 2020
    Jonbbrew

    Jonbbrew Member

    Paso Robles, CA
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    Ahhh...That makes sense. It looks like i am going to go with a AirTex E8090. I may even run a regulator but not really sure if i need that or not. If anyone has any thoughts of regulator or not that would be great. I also heard that regulators, especially ones without at return line, can cause more vapor lock issues.

    If anyone is looking for Airtex Fuel Pump specs here is the link. https://airtexasc.com/media/1178/16-universal-fuel-pump-applications.pdf
     
  18. Jun 8, 2020
    boopiejones

    boopiejones I can’t drive 55

    California east bay
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    I’m running a facet/purolator 12s pump. 198 motor, Rochester 2G carb. No regulator. Works great.


     
    Last edited: Jun 8, 2020
  19. Jun 11, 2020
    Rick Whitson

    Rick Whitson Detroit Area 2024 Sponsor 2022 Sponsor

    I live South of...
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    I used a fuel pump with the glass bowel on top, and indexed it 180* so the fuel goes in the rear and out the front to the carb, makes it easier to plum up the fuel lines. I made my fuel line out of brake line from the fuel pump to the carb, it works out well and there is no need to double flare the end you cut because the fuel pump doesn't make much pressure. My PCV is on the intake below the carb.[​IMG]
     
  20. Jun 12, 2020
    60CJ5

    60CJ5 Member

    Alabama
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    Nice highjack but back to the original question, any thoughts on something in the tank that could cause a fuel issue after being on an incline? It is the only thing I have not changed/cleaned/rebuilt
     
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