Problems at the pump... only able to pump 4 gallons?

From what Ive heard, you should be setting the pump on the slowest setting. I've also heard taking the fuel cap off and letting it equalize first helps too. And to answer your question, yes there could be more fuel that is indicated as well. Ive read on the site to not let it go below 2-3 pips in the wintertime as it may be a false reading. People have run out of gas on 2 pips before.

Funny, today I was down to 1 Pip (definitely risky behavior) and fueled up, took 8.6 gallons Thats a summertime fillup!! It was 10-15f here (Michigan) today so its not like the fuel tank bladder should've been back to its normal self. Weird. Truth be told, I was probably VERY close to running out of fuel - I wont allow that to happen again.

 

This happened to me while getting full service, the attendant flipped the nozzle upside down, and then restarted the pump. He said it was an air lock int the line, and has happened several times on my 07' prius.

 

In the past, were you in the habit of going BEYOND the first click-off of the pump ??

If so, it is possible that you have damaged the vapor recovery system due to OVER-filling and it might keep getting worse and worse until you are only able to get about one gallon in.

I assume no fault lights on the dash yet ??

Probably worth a shop visit to have it checked out.

 

Here's what I would suggest:
1) Don't take it to a shop, they will take you if they can and this just allows them to take you.
2) Fill it up, reset the MFD, and drive it for 400 miles. If your really worried about it, once you get to one pip on the guage, grab a 5 gallon gas can and put it in the back (I don't want you to get stuck somewhere in this crappy weather).
3) After 400 miles, fill it up and report the results here.

I know this is easy for me to say but, I'm confident you should be able to go at least 400 miles. Obviously there is more fuel in the tank than it indicates. This 400 mile cycle should fix your problem. I personally don't believe you'll need to use the 5 gallons but, you never know.

 

ALL dealers shops are not out to screw their customers at every opportunity.
Some only do in precise situations.......after they get your trust.

And I don't think it is obvious at all that the gas gauge is off.

There are other things that can cause it too.

Paying attention to the miles travelled, similar to what you suggest should shed some more light on the problem. It does appear that gas tank senders are a problem on older models.

 

Its obvious to me because I've seen this problem so many times including on my own vehicle (although not to this extent). There is no way a 12 gallon bladder could shrink to 4 gallons.

 

You are imagining things that are not in the posts.
Nobody ever said that.

 

No, I'm putting 2 and 2 together. The tank on a Gen II is rated to hold 11.9 gallons. The OP says he can only put in four gallons when his guage says empty.

You don't need to keep being a butthead to me, I'm actually trying to help the guy.

 

I'm having a similar problem with my tank on my 06. Went to Las Vegas last weekend, which is a 270 mile drive. I started with a full tank and when I got there, only 2 pips left. Filled up and only got 5.5 gallons in. Drove back only 170 miles and I was down to 3 pips. Didn't want to risk it, put in $15 worth of fuel (about 4 gallons) and it went all the way up to full again.

 

Very common scenario in these cars.

 

Yes I read about this all the time, but what surprises me is the ones that can consistently get 500 mile tanks. If this gas tank is a restriction, how the heck can they achieve 500? I've rarely gotten even 400 on a tank full.

 

I would only go to 500 if I was achieving 50+mpg (theoretically, that would leave 1.9 gals in the tank). It does take courage to go to 500. I have done it before but only a couple of times. You will likely have a flashing pip for the last 40-80 miles. Most of those you read about are in temperate climates like yourself. Those in cold climates seem to have more issues with bladders and mpg that don't allow for 500 mile tanks.

 

I almost never get down to the flashing pip, I would be too worried about being stranded. But I mean I haven't even gotten close to 500. I would get down to 2 pips when the car is at 300 miles on a good day. I just know my mileage is consistent because my fillups are usually fairly cheap, done with 7 gallons.

 

If you're only able to put in 7 gallons, you can easily go another 150 miles or more (If you're averaging about 45 mpg of course). These gauges, are so inaccurate, they need to be "reset" once in a while. My way of doing that is to run it down as low as you can stand. I usually do it like this.

1) fill it up until it clicks off then, add another dollar after that.
2) Drive it at least 400 miles (regardless of what the guage says)
3) Fill it up again until it clicks

This is just what I do. I'm sure I will get many retorts on why you shouldn't do that. From my experience, I can tell you, it worked for me.

 

Well, keep in mind that I saw somewhere (on here and I don't know if its true but it seemed to make sense) that you need at least 3 gallons added to the tank if you run it empty (it has something to do with the fuel pump thats internal to the tank).

 

After the Prius has run out of gasoline: if you don't disconnect the 12V battery first, and add less than 3-4 gallons of gasoline, the Prius may not recognize that you've added fuel and the car will refuse to start in an effort to protect the traction battery.

By removing and then restoring 12V power, the various ECUs will reset and the fuel gauge will register the true amount of fuel in the tank.

 

There is a black cable connected to the battery in the hatch. Once you access the battery, you need to unhook the black cable from the battery, wait at least 30 seconds then reconnect.