over-filling the gas tank

[TomFromStLouis]

Twice now I have filled my BJ8 gas tank, drove the half mile home and parked it. Next warm day there is gas seeping from the tank cap. What appears to happen is that the gas expands as it warms to room temperature from whatever temp it is underground at the station. The first time was a hot day and it percolated and bubbled out when I removed the cap. Perhaps some air was trapped somewhere in there.

Obviously I am putting too much gas in, although I just let the dispenser shut itself off and I do not top off.

Does this happen to you? Any ideas on how I can prevent it other than driving a few miles after each fill-up? My parking spot is level.

 

[AH100M]

I think maybe the air is expanding from the heat, maybe more that the gas. Is the vent in the cap clear?

I always fill my tank by sight, not by auto shut-off. But then I have a 100 and it's easy to just look down the filler neck and watch.

You need to stop the flow before the auto shut-off. Reminds me of the joke about the tourist on a bus who didn't know what stop to get off at to get to the art museum. A helpful fellow-passenger said to just watch him and get off at the stop before he did.

 

[anthony7777]

tomfromstlouis, if your filling the tank in relation to what your fuel guage is reading it might be time to have the guage re-callibrated, they are notorious for being innacurate

 

[Keoke]

Tom faget the fuel gauge that fella 7777's is talking about and carry a yard stick in the boot if it says 4" of petrol you are good to go. But stay outta da sunshine and only park on the level places.---Keoke-- Az-- :cowboy:

 

[anthony7777]

keoke, only you would enjoy havin a 3 foot long fuel soaked stick stuck in ya boot.

 

[ArtQ]

Actually, a 3 foot long quarter or half inch dowel works great---and don't forget to mark a spot on the stick that equals "full"!

 

[TomFromStLouis]

Okay, I am getting the message that the fuel gauge cannot be trusted. This I already knew, since it bounces around the full half when full and all around thereafter. So I fill up every 100 miles or so. It is the one gauge I have that is almost useless.

But are you telling me you guys use a dip stick WHEN filling up? Or that the only way to prevent this overflow is to watch and see when the tank is NEAR full? What I seek here is a way to prevent this from happening and I begin to think that I should drive a few miles just after each fill-up.

Thanks for all feedback!

 

[AUSMHLY]

Hi Tom,

I hear ya. I too would be frustrated with your situation. I would not want to have to insert a stick every time I fill up to find out where the gas level is.

If I may add onto Toms, question.
How does the gas pump know when to auto shut off? The pump handle rubber seal should seal around the top of the fuel entrance tube. I would assume it's pressure that triggers the stop, not liquid touching the pump nozzle. It would seem that Toms gas tank is filling more than it should? Or the gas is filling up higher in his tube than it should? Should gas be filling up the tube at all?

I'm not schooled enough to help you solve your problem Tom. I'll ask my Healey mechanics if they have come across this. Hopefully someone here will explain how to fix it, before my guys get back to me.

Best of luck,
Roger

 

[simco]

I am curious to know if anyone tried a voltage stabilizer like triumph or Land Rover uses to keep the fuel gauge from swinging. I'm new to this car and haven't screwed with this problem yet. 2 cent editorial

 

[nevets]

I'm also not knowledgeable about your problem but could there be a problem with venting?

 

[Keoke]

keoke, only you would enjoy havin a 3 foot long fuel soaked stick stuck in ya boot.

:wh----- :wh----- :wh----- :wh------

 

[AUSMHLY]

I am curious to know if anyone tried a voltage stabilizer like triumph or Land Rover uses to keep the fuel gauge from swinging. I'm new to this car and haven't screwed with this problem yet. 2 cent editorial

There is a fuel gauge dampener sold by Zim.
Per Zim, works with 6 and 12 volts.
Here's the link:Zim

 

[anthony7777]

ausmhly, that unit is a great idea, however it will not correct for the poor calibration of the gauge, installing the "stabilizer" will result in the fuel reading no longer bouncing around but it will remain incorrect, there is much info on this problem in our archives ive been trying to find it without success, i calibrated mine about two years ago and its been nuts on ever since, imho i think one would find carrying around a "stick" to be inconvenient, messy, a waste of valuable boot space, combersome, dangerous, and rather unglamerous. :frown:

 

[anthony7777]

Hi Tom,

I hear ya. I too would be frustrated with your situation. I would not want to have to insert a stick every time I fill up to find out where the gas level is.

If I may add onto Toms, question.
How does the gas pump know when to auto shut off? The pump handle rubber seal should seal around the top of the fuel entrance tube. I would assume it's pressure that triggers the stop, not liquid touching the pump nozzle. It would seem that Toms gas tank is filling more than it should? Or the gas is filling up higher in his tube than it should? Should gas be filling up the tube at all?

I'm not schooled enough to help you solve your problem Tom. I'll ask my Healey mechanics if they have come across this. Hopefully someone here will explain how to fix it, before my guys get back to me.
roger, you are correct, fluid contact does not trigger the pump shut off feature, there is an additional small tube that detects "air pressure" increasing and shuts off a valve in the nozzel head, without being sealed the build of this pressure would not be detected and the pump will simply continue tom pump.

 

[Michael Oritt]

The resettable odometer is a great gas guage.

 

[zblu]

Isn't the sensor a rheostat and it is the action of the attached float moving over the winding that gives the tank contents on the gauge?

And speaking of gauges had an old LandRover where the last quarter of contents took up about a third of the gauge face and as you went to full the spacing over the quarters decreased, ie its only the last quarter one is fretting on!

Been using the trip meter on my old 4x4 for years, just not worth pulling it all apart to get to the tank to replace the unit!

I use a bit of No.8 fencing wire as a fuel dip in the vw beach buggy

 

[AUSMHLY]

The resettable odometer is a great gas guage.

Hi Michael,

I wouldn't rely on that.
Maybe I am alone here, but my mileage varies too much between around town and highway.

This mileage issue is a thorn in my side. I get 12-21 mpg. What!?

So I can't rely on my odometer saying you have gone 125 miles and you have half a tank left. Not if I'm driving around town. I'd better make a bee line for the gas station.

I'm a member of the quarter tank club. I always fill up when the gas gauge estimates/guesstimates I have a quarter of a tank.

Maybe we should add, empty gas container, to the list of items to carry in the boot.

Cheers,
Roger

 

[John_Progess]

If you drive an MGT series you get used to using a stick as there is no gas gage! They have a dash light that comes on when there is approximately 3 gallons left. I have a calibrated piece of stainless tubing with the gallons marked off. You do get some strange looks at the gas pump. Have a good day!

John

 

[AUSMHLY]

Hi Tom,

I just spoke to one of my Healey mechanics.
He questions the gas cap. Is it an original BJ8 cap? Is it a good reproduction? Is it a working cap?

If the cap is good, then he says it's gotta be there is too much gas in your tank. It then maybe the gas station nozzle is letting too much gas in your tank.

I'm following this tread, just in case it happens to my BJ8.
Good luck,
Roger

 

[Michael Oritt]

Roger--

My 100 gives me 22-24 mpg consistently and at 200 miles on the tripmeter I am looking for a gas station. My wife's 3000 consumes a bit more and my limit of comfort with it is 180 miles.