Whenever I fill up, I cant get more than 8 gallons before the pump shuts off. I can always get at least three more in before it spills out so I know that something is wrong. How does the pump lknow when to shut off?

I have a similar problem on my 84.

The pump senses back pressure. If your vent line on your tank is restricted then the back pressure tends to build up faster than it should and the pump will shut off prematurely. If the vent line is plugged, you won't get in a quart before the pump shuts off. That's how mine is.

is the vent line connected with the charcoal canister? Could the charcoal canister be the problem?

Small and long filler tube. Just set the pump to go slower so backed up air can get out the filler neck. Even if vent tube is open, its still way smaller than capacity of the pump putting fuel in.

quote Originally posted by MordacP: is the vent line connected with the charcoal canister? Could the charcoal canister be the problem?

No... 2 vent lines... Vent line for fueling is next to fill line. Look inside at fill and vent lines near filling cap.

quote Originally posted by jscott1: The pump senses back pressure. If your vent line on your tank is restricted then the back pressure tends to build up faster than it should and the pump will shut off prematurely. If the vent line is plugged, you won't get in a quart before the pump shuts off.

Not pump... It's the Nozzles. See http://science.howstuffworks.com/gas-pump5.htm or http://www.straightdope.com...w-to-shut-itself-off

Some Nozzle are set to keep people from spill gas. Spill gas cause Station paper work and big spill can be an EPA problem.

Nozzle can be different from pump to pump yet alone from station to station.

Try this... Pull nozzle up instead letting it rest or turn it a little sideways.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top of every forum page...)

[This message has been edited by theogre (edited 12-27-2009).]

quote Originally posted by theogre: Some Nozzle are set to keep people from spill gas.

Yeah these nozzle in Texas have the vapor recovery crap on them and are a real pain. I know the vacuum hoses on my 84 are all screwed up and the charcoal canister is probably buggered up as well. I don't think it's a nozzle issue because I have the same problem at every pump I've tried.

Oh, i think we're beginning to shed some light on this. I will try to pump at a lower speed next time and see if that works. Good idea Roger. And the info theogre provided was also quite helpful

EVAP can, charcoal canister, will not cause this. EVAP system is too small.


And see 22p

Fill Vent is big. Like 1/2 inch I think.
EVAP vent is small... Line is small and EVAP can not move the volume in filling.

Try the idea I already said.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top of every forum page...)

I remember, even if i pull back the vapor seal thing and pull the trigger very lightly it will still shut off after about a tenth of a gallon. So I dont think it is backing up in the filler neck, but thats the only explanation that makes sense. I have no idea whats going on.

I had this same problem on my last car, a 1998 Mitzsubishi Eclipse. Something was blocked somewhere, and it was a royal pain to try to fill that car up! (Almost 3 times the capacity of the Fiero) My solution (Do this at your OWN risk) I enlarged the "cap" over the fill tube that has the little "flap on a hinge" in it. This was originally added to fill tubes when Unleaded gas came out. It is meant to keep people from being able to put regular gasoline into an unleaded vehicle. The regular nozzle at the pump was too large to fit into the smaller unleaded hole. I remember as a kid, I would use dad's lawn mower gas for my car now and then I had to put a screw driver in the little hinged door to hold it open, as the gas can at that time had the larger diameter tube that wouldn't fit hahaha

Now that regular is no longer available, it really is not necessary in my opinion. The flap looks as though it would seal to prevent water and such from going in, but it does not. Pour a little gas in the top of the tube, and you will see it goes right through the closed flap with very little restriction.

Again do this at your OWN RISK, as a Spark and gasoline do not work well together! I used a pair of tin snips, and cut 4 lines from the smaller hole to the outside of the that "cap". I then bent / peeled those 4 flaps inward increasing the size of the filler opening. That was the end of that, and I never had a problem adding fuel again. I know It sounds ghetto or redneck, but I am the only person ever to see the inside of the filler tube with the gas cap off

If someone has the tank dropped, and ALL fuel and vapors from the system removed, you could use a Dremell or other power tool to get a nice clean cut and remove the "cap" completely.

[This message has been edited by JohnWPB (edited 12-27-2009).]

Look at nozzle. Look for a small hole. On bottom, 1-1 1/2 inch from end.
The small hole is the shut off hole.
That hole... position matters.

Turned nozzle up to 45* in CW or CCW.
or
Push nozzle in and Lift nozzle handle instead of resting it during pumping.
and/or
Slow the nozzle. Warning. Too slow can cause spill. Depend on Nozzle and Nozzle condition.

No Luck?
Check the fill line and it not blocking.
Check fill and vent rubber line and hard line for not crunch it/them.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top of every forum page...)

[This message has been edited by theogre (edited 12-27-2009).]

Most of the nozzles in Texas won't even go unless you push then in all the way.

And when I replaced the tank on my 84 the vent was a tiny little line, no where near a 1/2". It must be plugged up is the only thing I can think of since every pump nozzle I've tried will shut off immediately after I start pumping. Either that or my fill tube is somehow crushed.