NO fix for Prius Gas Tank Filling Up Issues

If the Prius tank holds about 10 usable gallons, the last half of the tank is 5 gallons. Gasoline weighs about 6 pounds per gallon, so that last half of a tank adds about 30 pounds to the load.

Does an increase of 30 pounds trim off 2 mpg?

Tom

 

I absolutely agree that this is a problem. There's no way to accurately gage mileage without knowing whether you've filled the tank. I have a 2008, which I fight with at any pump, any time, anywhere I gas up. The only consolation is that now I know I'm not the only OC out there who wants to keep an accurate account of mileage.

 

An easy fix is to simply stop at a filling station when you get to two blips on the gas gauge. If you are in a desolate area then you fill up at every station possible. This is what people did before they started worrying about digital gauges and dashboard readouts.

 

It's not a "fix", it's an inconvenient accommodation to a faulty design.

 

The gas gauge on my Gen II is very consistent at the lower levels. Like most gas gauges, it's not very linear, but when it gets down to the bottom I know I need gas.

Tom

 

OK, I'm here a bit late and missed some debates, but qbee42 posted this same information back in 2/2008. I then posted, "OK, I read the document from Toyota Technical Training. I read the procedure for refilling the tank (page 11 of 18). It says, "When refueling, the engine is OFF and the EVAP VSV is CLOSED (OFF)." But Toyota says "the engine is OFF," not the car is off. Page 1 states, "A bladder fuel tank is used to reduce fuel vapors when the vehicle is parked, during refueling or while driving." So I am wondering specifically what valve is open that would be closed if the car was off. It says the Purge cycle will only occur when the engine is running, so maybe if the engine was running and it was being refueled and at the same time it decided to do a Purge cycle something unusual could happen. But other than that, and if the engine is off, I can't see any difference between having the engine off and the car off, at least as relating to refueling. "

Nobody ever answered this question, so once again I am asking.

Also, there has been misinformation posted about the Prius and Ready mode. If the Prius is shifted to N the engine will not start, and if it is running it will not stop, at least not until it runs out of gas.

 

I used to have the schematics for the fuel system. I know they have been posted before. Perhaps someone still having a copy will post them again.

Tom

 

Here is the link for the Prius fuel system:

http://www.autoshop101.com/forms/Hybrid13.pdf

(Figure 3.3 on page 3-5 Toyota Hybrid System Diagnosis - Course 072)

 

You are experiencing a difference in pressure from the gas going in and your Prius trying to control that flow and the pollution from the emissions that goes along with that flow.

This is common and it's because of two things:

1. your Prius has a specialized gas tank system that minimizes gas fume emissions

2. each gas pump is different and you will have different results using different pumps at different times of the day (even at the same station)

 

We have a 2001 Prius series 1 that has started to show 1 blinking silver bar, yet when we fill it up it only takes 6 or seven gallons. this is compared to up to 11.2 gallons for a fill with the blinking bar on morning startup and running to work and back home, filling up near home. drive distance about 12 miles round trip. We had the traction battery replaced at 122k miles and the full diagnostic recommended considering changing the gas tank due to deterioration of the bladder.
No guage problems then.
I have worked on cars for years and feel the problem is related to the bladder bag snagging the sender float in some way giving false readings. We plan to keep the car and will buy a new tank when we ship the next kid off to college.
D.

 

Silversurfertx reply
another member on the forum named Galaxee had an excellent teardown of a Prius gas tank that shows the bladder and gas gauge float are in two separate areas. My post was inaccurate. Sorry.

 

I just bought a 2008 Prius a week ago today and bought gas last night with the fuel gauge showing one pip. At first it DID only let me put a little gas in, but I kept trying and experimenting with how hard I squeezed the handle, and finally got in somewhere over 8 gallons, and the gauge showed full when I left the station. Unfortunately I didn't save my receipt, but will start saving them all so I can track this situation.

 

Our dealer told us that a smaller tank becomes an issue if you wait until the tank is really empty before you fill it. We used to be able to get more than 11 gallons in a fill up, now we're lucky if we get to 7.9. Once, even, after the nozzle shut off, gasoline started surging out of the tank. It was mildly terrifying to watch wave after wave of gasoline burp out of the tank. The dealer said it was the bladder tank doing that. I wish we'd known about the "don't wait till it's empty to fill it up" advice when we first got the car. The smaller tank is a real issue. Not everyone experiences it because they may not have waited until the tank was empty to fill it.
Who knows, maybe some of what I've just written is really true.

 

I think that is very good grounds for some sort of class action lawsuit. Gushing gas doesn't go over well in court. Can you get a statement from your dealer, ie: will he go on record?

 

That salesman doesn't work there anymore; not sure where he went. Interesting point, though.

 

I regularly get 10 to 11 gallons in my Prius and I used to top off which always would cause the tank to vomit out gas uncontrollably. So let me know what you guys come up with as I know I could put less fuel in my tank. That is not the point if I am told I have an 11.9 gas tank I expect it to hold that.

 

I've only had the gas gushing problem twice. About 3 years ago I left the pump unattended and came back to see fuel pouring out of the filler cap. After removing the nozzle, fuel continued to leak out of the filler neck for about 10 minutes.

Last night I drove for about 20 miles with the low fuel light blinking; which I never do. When I filled the tank, it's burped out a small amount of gas. I had only put 8.1 gallons in to fill it.

 

My problem is a little different...The last couple of times Ive filled up, the bars arent moving-so I assumed I have a indicator problem. But tonite, I put in 15 gallons of gas (impossible, I know)! Where did the gas go? It still showed empty, pulled into another gas station & put 3 more gallons in. Major problem here! I'm kinda freaking out, because I have 300 miles till home! Any ideas?

 

I wonder if the fuel bladder ruptured and your fuel is leaking into another area.

 

If you didn't spill 4+ gallons of fuel on the ground, then my guess is that the gas station pump cheated you.