Filling tank with gas

F Body General Discussion

  1. droptop

    droptop Well-Known Member

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    Just checking to see if anyone else is having the same problem when refueling. Car is an 80 RR. When I first start to refuel, I have to keep moving and turning the nozzle to get it to take fuel without kicking off. I wind up holding it turned to about 4 o'clock and as slow as the pump will allow. I don't dare try to use the little lever lock or let go of the handle. Also when the tank finally gets full, with the flow so slow, it is hard to tell when it is close to full and I usually wind up with fuel running down the side of the car. Could I have some type of vent issue? Any suggestions welcome.
     
  2. 80mirada

    80mirada Well-Known Member

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    Your tank vent could be plugged.
     
  3. Silver Bullet

    Silver Bullet Well-Known Member

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    I have the same problem with my '77 and '79. I think it is the newer fuel nozzles. I never had that problem back in the 80's and 90's. The nozzles don't go in far enough. I also have to rotate the the nozzle to a 3 o'clock position to fill so the pump doesn't kick off. What I do is take a wad of paper towel from the cleaning station and put it between the nozzle slash guard and the panel. That way the paper towel absorbs the gas instead of running down the car.
     
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  4. old yellow 78

    old yellow 78 Well-Known Member

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    That's a good point. I wonder if they did change the design somehow. I dread putting gas in OY because unless I go very slowly, it easily backs up. I also don't remember it being much of a problem when I had F's as daily drivers.
     
  5. Aspen500

    Aspen500 Well-Known Member

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    I always have to fill mine at about half throttle.
     
  6. BudW

    BudW Moderator Staff Member

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    There could be several reasons for this – but I suspect the most likely cause is the vent. The vent is actually the charcoal canister and is located under the hood passenger side front corner.

    There will be either 2 or 3 ports on the Charcoal canister. The small port (small vacuum hose) goes to the base of carburetor and it helps to remove the fuel vapor from the canister (ie: pulls the vapor into engine to get burnt).

    OF the two large ports, one goes to the fuel tank and other goes to the top of the carburetor. My ’77 has no large hose going to carburetor and that port is plugged on charcoal canister (from the factory) – but most FMJ’s will use that carburetor vent (it catches any fuel vapor from carburetor after shutoff and stores it).

    What I recommend to do is to locate and disconnect the large hose that goes towards rear of car from the charcoal canister – and then fill the fuel tank. If tank fills better, then the filter on bottom of charcoal canister is dirty (or canister is stopped up). In many cases, the filter can be removed from charcoal canister and cleaned or replaced – but that is not the case on all charcoal canisters.
    77 FSM pg 25.41c.JPG

    Charcoal Canister Filter.jpg
    Note: the owner’s manual on my ’77 Wagon says the charcoal canister filter (called a vapor storage canister filter element) is to be replaced every 30k miles (48 km) – but I don’t recall ever changing one as part of normal maintaince.


    If disconnecting the hose did not do the trick – then a person will need to get car jacked up some distance of the ground (you will need plenty of wiggle room under the car). Start to trace the three metal fuel lines going from front to rear of car (5/16” will main fuel supply line, 1/4” will be fuel return line and 3/16” will be fuel vapor line (aka the fuel vent) - which is the smallest of the 3 lines). Check for bends, kinks and for rust. I prefer to use a small flat screwdriver, but an ice pick also works. Anyplace you see that might be rust – poke it. If your “poker” dents or goes through the tube – then you have a rust repair to make (and maybe more). These tubes can rust from inside out (and outside in) and rust will restrict airflow through an already small line.

    The rubber hoses can also come apart and a small flap inside of hose can restrict air flow (or fuel flow). Sometimes the rubber hoses that do that are generally also cracked on outside. If a car has sat outside for 25+ years – it is not uncommon for those hoses to be on their last leg . . . several years earlier.

    A few years ago, my '86 Fifth Ave was getting poor mileage and hard to start in morning (excessive crank time). Come to find out the “hidden” hose (by where the firewall is at on passenger side of car by frame rail, a commonly overlooked hose), the main fuel hose had cracked to point it was leaking fuel after car was turned off. I changed all those hoses and several problems was fixed.
    Note: 3/16” fuel hose is expensive!
    I needed just under 3 foot of each size fuel hose – but your vehicle might vary. Measure first (at tank, the hidden area and underhood (to fuel pump, to fuel filter and to charcoal canister)!

    It might be helpful to have a helper when working on the main fuel line hose. That line is full of fuel and you “could” siphon the entire tank if not careful. The fuel return line is also full of fuel, but it will not matter if any leaks out (except for the minor loss of fuel and any that gets in your face).

    A rusty line repair can be done on car – but you will need to pull line out of the way some, get a pipe cutter and cut a decent section of line out and replace with a section of rubber fuel hose. This size pipe cutter works great on-car.
    Tube Cutter, Small.jpg

    Hopefully this helps.

    Currently, I have no problems filling the fuel tanks on either car (’77 wagon or ’86 Fifth Ave) with the exception the fuel filler nozzle wants to fall out of the wagon when in use. I have to keep my hand on it when filling – which is not a concern. The concern I have is the fuel filler hole is down lower than I like, and it requires for me to bend down when filling – which is, um, uncomfortable to me.
    BudW
     
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  7. old yellow 78

    old yellow 78 Well-Known Member

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    Thanks BudW. Good info to know. I want to take OY over to a friends garage who has a lift and check it out - but not venturing out on snowy, icy, salty roads! No way. So another job for Spring. I also find the fuel filler hole to be inconveniently low. Didn't seem to be a problem when I was younger! :rolleyes:
     
  8. volare 77

    volare 77 Well-Known Member

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    80 may be completely different but on my 77`s( both early 77`s) the vent is at the top of the tank. The hose and metal line is small. I want to say the hose is around 3/16 or so. It connects to the roll over valve. I don`t remember having any fueling issues but I tend to stay with it and not go wide open on the nozzle as i don`t want to get gas on the paint.
     
  9. volare 77

    volare 77 Well-Known Member

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    My 73 Charger was worse. It was behind the tag. At least if it spilled it didn`t get on the paint.
     
  10. Oldiron440

    Oldiron440 Well-Known Member

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    It seems like at one time I remember hearing that the better the fuel was the more it would kick off the filler. I wonder if the alcohol in the fuel has something to do with it.
     
  11. XfbodyX

    XfbodyX Well-Known Member

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    Ya got to remember things are not designed for our old cars, I run into some new pumps with even my new Dart that kicks them off if at the wrong angle.

    And ive noticed the same thing at some stations that you can kick the other guys off with your pumping activity.

    F-s have always sucked at the pump to even put gas in at times as I recall even when new it was one of the biggest pet peeves I had when they were new.

    Ive wondered if one cut out the little section right inside the filler tube if it would help or just make it more apt. to run out around corners.

    I used to know the actual measurement but on the early F-s its not a huge jump from the full fuel level and the actual inlet height.

    Which kinf=da makes me wonder with all the mods we do on our cars why not retro a behind the plate or a higher fuel inlet?
     
  12. Aspen500

    Aspen500 Well-Known Member

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    The low height bugs me as well. Like you said, when I was younger..............The venting is good, the rollover vent valve was brand new (the tank was also) and the canister filter was also new. The car had been the same way since the day I bought it 32 years ago.

    My '08 Mustang has to be fueled at half throttle also. Nothing wrong with the venting (excuse me, fuel fill vapor recovery system:rolleyes:). It's the angle of the filler neck and it actually goes down hill and then back UP hill (what were the thinking?)slightly before going down to the tank. The saddle type tank makes it worse where the left side fills first and then it has to run over the driveshaft hump to fill the right side. It was a complaint from day one with '05 and up Mustangs but you learn to live with it.
    What I'm getting at is the engineers don't think some things through completely then and now.

    On the other side, my '96 Dakota can be fueled WFO on the nozzle with no spit back or clicking off.
     
    Last edited: Feb 20, 2019
  13. Oldiron440

    Oldiron440 Well-Known Member

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    I'm sitting here trying to remember if I've had problems filling my Fbodys, the wagons were thirty years ago and the coupe drank from a barrel.
     
  14. Aspen500

    Aspen500 Well-Known Member

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    Edit: My car did fill fine for a couple years back around '95-'96 when it was in it's semi-pro street mode (to this day, don't know WHAT I was thinking). Open the trunk, take the cap off the fuel cell and let 'er rip! lol.
     
  15. droptop

    droptop Well-Known Member

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    Well, it is good to know that I am not the only one experiencing this problem. The charcoal canister under the hood does not have the vacuum hooked up to it. Had one of those let go and filled the carb with charcoal. Talk about a bad day. I wouldn't think that would effect the filling problem, because the car is not running when putting gas in it anyway.
     
  16. Dr Lebaron

    Dr Lebaron Well-Known Member

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    Had that problem with previous Mopars, but haven't had problems in yrs, due to learning
    Don't fill up hot.
    Don't fill to the brim. I guess a dollar amount v/s the gauge and usually spot on.
    I use non ethanol gas only.
     
  17. Oldiron440

    Oldiron440 Well-Known Member

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    I only use ethanol fuel in drivers.
    Plymouth will be e85 only.
     
  18. Justwondering

    Justwondering Well-Known Member

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    2004 Chevy 2500 truck, since new, never accepts gas without holding the nozzle up and out about 1 1/2 inches.

    My solution was to have the family trust gift the truck to my older brother after my dad died. I'm never bothered by the slow fill now. o_O

    Every mechanic I asked told me the problems began when the gas tank filler tube was redesigned to prevent people from siphoning gas. But for the 70-80 vehicles, the plugged vent seems to make more sense.

    JW
     
  19. Aspen500

    Aspen500 Well-Known Member

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    At some point they put either what looks like a ping pong ball is the end of the tube or a spring loaded flap. It isn't really to prevent siphoning (although it does), the main reason is to prevent fuel from going up the tube in the event of a roll over, which can cause the cap to potentially come off. They work fine for that but also cause a restriction in the tube that can cause fuel spit back, which shuts the nozzle off.
    I know my Aspen has a baffle toward the bottom that sticks out the end of the filler tube. Not really sure what the purpose is though.
     
  20. Super Coupe Man

    Super Coupe Man Member

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    Yeah I have the same problem with my 78 Super Coupe some gas pumps are ok and some are not