TSB Released on Fuel Gauge Innacuracies

Update on the gas gage "fix".
On my second fill up since the 2nd dealership visit (regarding troubles with the gas gage) an old problem reoccurred. The gage failed to come off the full indication until around 210 miles. As I was driving home yesterday the gage went from one bar down from full BACK TO FULL at 283 miles(reference attached photo)! I didn't know the car could "make fuel". I think I'll run a couple more tanks through to get a better idea of inconsistency.

 

living in colorado?? have any severe hills in your neighborhood?

 

Hills or no hills, I don't think he's getting 210 miles on the gas supposedly available in the first bar 'for real'

 

must be the high attitude and reduced gravitational forces not allowing the float to sink properly. in low gravity situations, the float will sit higher in the tank because of the lack of gravity pushing the float down to its calibrated level.

then again...

maybe not.

 

I believe it has to be somehow related to the tank sensor and its arraignment to the tank. At the time the gage "added fuel" we were on flat terrain and the temperature was 62°. With the previous tank of gas the gage performed normally. It will be interesting to see how many gallons it will take for our next refill.
As I stated earlier this month with the 10.3 gallons of usable fuel in the tank (according to the service manager) I have to monitor the amount of fuel I was able to put in verses the miles driven very closely. We don't want to get stranded in the foothills again. Stranded motorist along that rode get about as much attention as a dead tree in the forest.
I am definitely curious as to the physical arraignment of the sensor area of the tank and if anybody has come across any drawings or photos I truly would like to see them. I worked on a project related to measuring fluid in a flexible bag and even in a controlled environment it was difficult to attain consistent readings.
I'm feeling like the bug and not the windshield on this one. But I do feel the more information I can provide Toyota on this problem the better it will help them and us in the long run.

More to follow...

 

Second tank fillup - Gage reading half full, miles = 346, mpg = 44.5, gallons to fill = 7.914.

It appears consistency has disappeared. One more tank full and it's back to the service department.

 

Sounds normal to me. That's about what I get at half a tank, with MFD showing 55MPG.
Gallons per pip will vary a bit. I did a test on 2 tankfulls for the first 6 pips, and there was a variance by as much as .25 gallons.
Also, consider there may be a great variance on # of gallons from full to the first pip, as that depends on how 'full' the tank was.

Everyone seems to register the gauge by miles, but that is not accurate. The gauge is supposed to read gallons, not miles. One pip at 40MPG will give you less miles than at 55MPG.

Also, some have complained that the blinking pip reads too soon, as they can drive 2 gallons worth.
I believe Toyota did this to give a cushion for fuel movement at the bottom of the tank. True, the gauge has a 'tilt' sensor, but if there was a gallon of usable gas at level ground, then you go uphill, the gas may end up at the wrong end of the tank, thus ending up with no gas to the engine. Adding more gallons to the blinking pip would allow for the fuel shifting.

 

with a regular tank, that might be plausible, but with the bladder system, i think that even a severe slope and very little gas would still be pumped.

the bladder (as i understand it) has no air space so the bladder collapses as the gas is consumed. this creates a vacuum like suction that should squeeze every drop out as there will be an overall negative pressure created by the combination of the gas being sucked out by the fuel pump and the weight of the bladder collapsing in on itself.

 

We just received our 2005 last week. The first fill up was yesterday. The blinking bar came on when the odometer read 486 miles. The odometer read 502 when I fulled up. The gas pump cut off at 8.9 gal. The MPG for the tank was 51.8 on the screen.
Can anyone tell me how much fuel is in the tank when the blinking bar initially comes on?
The car was delivered at the end of October so my assumption is that it is equipped with the most up to date fuel system changes. Thanks, Mike

 

tough to say... but based on operations of previous toyotas ive had which all had low fuel indicators of one type or another in addition to the gas gauge, they usually come on at about 3/16th of a tank. from what ive noticed with other Priuses on this site, that seems to be a good guess (i have only seen the blinking bar twice albeit briefly)

 

Evan, Thanks for the info. I guess the prudent thing to do is just refuel when it starts to blink and forget about being too Type A about the whole thing. As a majority of the group users say "Just Drive it".
I must say that our Prius is something special, I have had so much fun driving and just fooling around with all the unique features. It is the best car we have ever owned from a technological point of view and also very well made. Mike.

 

I have had my car since early December 2003. I have decided not to get the fix. The way I handle it is to drive 400 miles then get gas at the next handy station. The last bar starts flashing anywhere between 325 and 370 miles, the pump usually shuts off around 6-7 gallons so I keep clicking the pump until 8 gallons is pumped. I usually have 50 - 52 MPG for tankful.

 

I live in Los Angeles and took mine to the dealership over a month ago and they still don't have the TSB parts in. Last week they told me that it was back ordered nationwide. Has anyone else heard that too?

 

I had just the opposite experience. Parts were ready in less than a week. I had to wait a few days to drive my real miles up to the replacement ododmeter setting.

 

This could get interesting...

:roll: My early '04 falls within the both Meter and Pipe range. Called the Service Manager at Richardson Toyota (Dallas TX) today who printed out the TSB and proposes to order the parts tomorrow (Tue 11/16) together with the updated DVD for the Nav System. This dealer has not done the Fuel Gauge update and did not yet have info on the DVD replacement.

I am ambivalent about having them do the Fuel Gauge TSB. Will keep the group posted on my experience.

-Charles Suitt- Dallas TX :|