Fuel Pump Got Noticeably Louder

Discussion in 'Injection Tech' started by MrKenmore, May 26, 2019.


  1. MrKenmore

    MrKenmore High Wheeler

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    Hello all! I have about 3,000 miles on my HFI system (system complete February of 2019). It's been terrific with no issues. Today, all was well in the morning. In the afternoon, when I went for a spin, I noticed the fuel pump was considerably louder. I use MrsKenmore as a good gauge of how loud or not loud it is. I have rubber isolators so when all is well I know it's there but it's not too loud. Any ideas what could cause this? I do have only about an 1/8 of a tank now so maybe the pump is stressing a little? Outside temps are 85 degrees. No visible debris in the filter. Thanks.

    FYI - Supply fuel line is 3/8" NiCopp and return is 5/16" NiCopp
     
  2. stevewillis

    stevewillis Farmall Cub

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    Did you change or clean your fuel tank when you changed to injection? If not, perhaps some crud from the tank has fouled your fuel filter with the increased flow. Otherwise, is the noise reduced if you remove the fuel cap?
     
  3. stevewillis

    stevewillis Farmall Cub

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    Sorry. I’m reading on my phone and missed that you checked the filter.
     
  4. MrKenmore

    MrKenmore High Wheeler

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    You're a good detective Steve. I did recently change my fuel cap (to a Stant 10623). When I unscrewed it in the garage (Scout not running), it made a decent whoosh sound. My prior cap never did that. I thought I got the same vented style as before. Old one was locking (Stant 10491). I also filled up at the gas station to 3/4 tank. The noisiness has definitely subsided and things appear and sound normal. My guess is the pump was working overtime in a negative pressure environment and it didn't like that very much???? I put back on the cap I got originally with the Scout. Not sure what function that one is (venting/non-venting)!
     
  5. Dana Strong

    Dana Strong Dreams of Cub Cadets

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    Some days ago I was looking at the Stant application table for pre-'94 vehicles (a .pdf Here), wanting to know the correct replacement for the non-vented caps on my 800B. That table doesn't list any for my year and model, and looking up either the 10623 or 10624 on Ebay and checking/according to the automated 'application' chart under a few ads, neither is supposed to be correct for the 800B. I now have what looks like the 10624, which leads me to assume those are both vented. Any chance your new one (10623) was actually a different model put into the wrong box at a store?

    Stant has a technical service department and I expect a call back about my needs.
     
  6. Greg R

    Greg R Dreams of Cub Cadets

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    I'd say there's something wrong with the new fuel cap. I have used the 10623 fuel cap on the 67 Travelall, the 60 Ford 1/2 ton, even a 1965 Gravely with no problems in fuel delivery and never had a woosh pressure or vacuum. Stant does list the 10623 and the 10491 locking cap for non-Calif non-emission Scouts.
     
  7. MrKenmore

    MrKenmore High Wheeler

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    Oh there is a significant chance that occurred. I love Amazon but sometimes I don't understand what I get. What I received was a gas cap in a Carquest box with some other number. It fits but I bet it is not vented. Looking at the cap.....it does have the Stant "S" logo on the inside. It does make a rattle when you shake it.

    Greg R - I wish they would describe the caps as "vented" or "non vented".

    I have no liquid vapor separator / charcoal canister so the cap is the only means of keeping the tank pressures balanced. Not that the liquid separator would do a great job with that tiny orifice.
     
    Last edited: May 27, 2019
  8. MrKenmore

    MrKenmore High Wheeler

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    Pondering this further, perhaps the cap is the correct vented version but the vacuum relief function is insufficient for the fuel system I have.
     
  9. Dana Strong

    Dana Strong Dreams of Cub Cadets

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    Your system recirculates fuel, which carburetors don't do, but still uses the same amount to run the engine. Even a poorly-vented cap sould have slowly allowed air in and prevented the "wooshing'. Either the cap is defective, or the wrong one.
    I would call Amazon Customer Service and 'complain'/explain the problem. Their phone number is 1 (888) 280-4331.
     
  10. stevewillis

    stevewillis Farmall Cub

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    I am also using a Stant 10623 with my EFI setup with no other venting (liquid/vapor separator and charcoal canister removed). It is vented, and seems to have resolved my issues with the previous cap, but I had the opposite problem--I got a face full of gasoline when I removed the cap. My issue has similar symptoms as yours with an audible change in the fuel pump.

    A thought: perhaps there is an issue with your fuel pressure regulator in the throttle body or the return line that is causing the fuel pump to reduce the tank pressure? I am way out of my depth and would seek Bill Hamilton's input.

    Another thought: maybe I also have this problem, but it is masked by the compliance of my poly tank and/or my 7200 ft elevation.
     
  11. MrKenmore

    MrKenmore High Wheeler

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    Well, I drove all over today for about 4 hours. No issue with the different gas cap.
     
  12. JayKray

    JayKray Farmall Cub

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    @Mr Kenmore, what is the different cap? I also am using a 10623 cap with my closed loop/non charcoal canister/non vapor recovery Hamilton fuel injection setup and I also get a woosh sound when opening the tank. I thought this was somewhat normal as I have read here that the "vented" cap holds a certain amount of pressure differential, but lets go if it gets to a dangerous level. Last time my fuel pump sounded loud, it ended up being the hard line was touching the frame. I have since isolated that issue.
     
  13. MrKenmore

    MrKenmore High Wheeler

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    The different cap appears to be a vented style. I cannot be 100% certain though. But then again, I cannot even be sure the new one I got is the correct 10623!! I wonder if it was a combination of low gas in the tank and also the sun shining down on the bed and heating up the area cause the gas to expand. JayKray - Do you get a whoosh every time you open the cap?
     
  14. stevewillis

    stevewillis Farmall Cub

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    I might have misunderstood. If the whoosh is expelling air from your tank rather than drawing it in, that is the same problem I had that was solved by the 10623. It didn’t happen every time. I once got a powerful blast of liquid gasoline in my face, and was lucky to have it happen at home where I could stumble inside and rinse my eyes. The tank was close to empty.

    If this is the case, I’d think you might have received a bad 10623 or an incorrect part.
     
  15. JayKray

    JayKray Farmall Cub

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    Funny you should ask! I drove the scout to and from work yesterday, roughly 54 miles total and stopped on my way home to fill up. No woosh, no drama, no nothing when opening the tank. I think it does very much have to do with a very empty tank and the weather. It happened to be a cool grey day here yesterday. The time I got a woosh, it was a pretty warm sunny day, so the tank may have created its own pressure due to warm expanding gas vapors. I also received a handful of gas then first time filled the sealed poly tank all the way. I have since been careful to stop pumping before it is all the way full.

    I will say that I have somewhat limited experience with a completely sealed system as I had a leak in my old steel tank and could not get the sender to seal on the poly tank. I recently purchased a sheet of nitrile, made a new larger sender gasket, and used permatex #2 on both sides. That seems to have done the trick.
     

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