Gas tank dilemma

[gerviswaddell]

Ok, Im not sure how this system works, but when filling up the tank, there is some kind of feedback between the pump nozzle and the tank itself, Im sure everyone is familiar with this process, when the tank is full, the pump cuts out. simple right? On my Terc this cut-out happens early, sometimes very early. At first I was convinced that I was getting poor mileage, but if I check the mileage via how much fuel is used to fill up the tank its all right...problem is when I last filled her up after a 200+ mile trip, the tank topped out at only 11L...so what is going wrong here? how do I get the tank to communicate properly with the pump?

thanks,

Dave.

[terkill]

this happened to my el camino but it was because the aftermarket gas tank didnt fit as well as the stock. what i had to do was hold the pump partway out of the hole so the gas overflowing on the latch at the bottom of the arm didnt trigger it to shut off, the gas flowed under it, also hold the handle at halfway pressure at the same time so it isnt a huge flow of gas. im trying to find a diagram to show but none work. (when i went to very old style gas pumps they worked fine) the main problem was the seal between the pump and the tank*

[Neu]

Okay, the actual shut off of the gas pump happens when gas flows over a small little hole on the underside of the gas dispensing nozzle. It's just a small hole on the underside of the gas nozzle. When gas hits it, it shuts off. It's really simple.

The reason this happens to your car is the tank isnt' set up right, they're trying to fill it too fast for your nozzle. Some how the gas is coming back up, or not going down fast enough. Get yourself a custom made tube coming off of the gas tank inlet to let the air out, sometimes it'll bubble and cause it to come back up, like when you're draining a gallon of water out of a jug, it burps kind of.

[Petros]

fuel is bubbling up the filler neck and tripping the nozzle shut-off. You either have to fill it slower, or alter the tank to allow it to fully vent with a breather tube from the top of the tank.

BTW, I have never managed to get more than a bit over 11 gal of gas in any of the Tercels I have owned. The owners manual says the tank is 13 gal. but either that is a lie, or 2 gal of fuel (or volume inside the tank) are not usable to the car (out of reach of the pick-up). Anyone know which it might be?

Is there a way to make all 13 gals usable? It would give me over 60 miles more range per fill-up.

[keith]

If I recall correctly, don't stick the nozzle in all the way, back it out about a half inch from all the way and it will fill up normally.

[takza]

I keep the nozzle out maybe 1-2"...used to try topping it up in summer....but once it shuts off...I can't get more in without overfilling it. I've put in around 12.5 gallons I think.

If you are using the vapor recovery nozzles...with the corrugated rubber cover...they shut of much sooner.

If you keep a 3 tank avg...you can factor out those unusual fill ups. If you have a short fill...you will think you've done real well...until the next fill up where you will likely makeup for the short fill and think you did poorly. Avg the 2 and you get a valid number. 3 tanks smooths it out.

[Neu]

As to the 11 gallons being the most you can get in there, maybe there's a lot of dirty in your tank? I've heard of it happening in a friend's old, old farm truck ford. It got to the point where he could only get 7 gallons in his 17 gallon tank.

He dropped the tank, and found a LOT of sediment. After he cleaned it up he could fill it to 17.

[Petros]

I doubt it is full of dirt, I have had the sender out of it and looked inside, it was clean. I think once I got 12 gallons in it when I was about out. But one time I ran it dry and had to coast down a hill into a gas station. The gauge looked like I still had at least a gallon left, my low fuel light did not come on (which I found was not working), so I do not push the bottom of the tank anymore.

How much does everyone else usually put in it whey you fill up? I am usually between 10 and 11 gals. Even with the gauge at empty I only once have put 12 gals in it. Does the tank actually have 13 usable gallons?

[takza]

I've run dry 2XS...and it doesn't sputter any...it just quits. I usually refill at 10-11 gallons down...though I wouldn't be afraid to go for 12. It's just that in winter...my gas gauge reads differently (ran out)...in summer when it gets low...it is very accurate and the light still works. I take them for their word...13.2 gallons.

[Neu]

My gauge is really dumb. The light comes on way before it's really that low. Once the light comes on, I can generally go 80 miles. The gauge will go completely under the E line, then you should really, really worry.

[sdoan]

In both my Tercs the warning light comes on at almost exactly 10 gallons. It took about 8 years before I actually ran it long enough to put 11 gallons in it. The most I've ever put in is about 11.5 - in about 395 miles. It's never run out of gas, so I don't know what the limit really is. I always assumed it would go to 13 gallons before running out, but not so sure now.

[Neu]

In both my Tercs the warning light comes on at almost exactly 10 gallons. It took about 8 years before I actually ran it long enough to put 11 gallons in it. The most I've ever put in is about 11.5 - in about 395 miles. It's never run out of gas, so I don't know what the limit really is. I always assumed it would go to 13 gallons before running out, but not so sure now.

When the light comes on, in my experience, that means 85 miles or so. So about 2 to 3 gallons.a

[Jarf]

The shutting off phenomena is a result of the fuel bubbling up the intake tube, which is what would normally happen when the tank is becoming full. If your problem is a new (no recent fuel system repairs/same filing station) then you have to look into the tank venting, it was vented from the factory and the system works well when it is whole, rust can play all sorts of nasty tricks on fuel systems, the worst are the ones that allow only vapour to escape/enter. You should not need to add any vents to your system, just make sure the ones that are there are functional.
A fuel gauge is supposed to represent what is in the tank, they are not always accurate, but it is still better than using a stick to dip the tank.
Having a 2Gal reserve isn't such a bad thing anyways.