Prius 09 Fuel Indicator Question

If you've read any of the Stickies in this Forum, you've found out that the gas gauge really is more of a "guess gauge." The reason is the bladder in the tank.

You never really know exactly how much gas you have left, so you need to be cautious.

One safe way to measure where you are at in terms of gas in the tank is to multiply the last fill-up quantity by the current MFD FE reading (assuming you reset it during the fill-up). In your case, you put in 9.265 gallons. If your current MFD reading is 51.5 MPG (as was the case at your previous fill-up), then you could expect to have 477 miles available from that fill-up (9.265 gal. x 51.5 MPG = 477 miles).

Because you've reached 475 miles, that means you are, basically, at the same point you were when you last filled up the tank.

A real danger is to assume that because you put in 9.265 gallons, you still have 11.8 - 9.265 left in the tank. The bladder makes such calculations and assumptions unreliable. I've never been able to put in more than 10.1 gallons -- even when the final pip was flashing.

You can go ahead and push it at this point, but if that last pip starts flashing, I wouldn't waste any time trying to get to 500 miles. Go to the nearest gas station ASAP.

 

Why would anyone want to push it?

Opportunities come up with friends & family. Last thing you want to do is have to stop for gas when it's inconvenient... or worse, have no where to stop available.

Why isn't a range of 450 miles enough?
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Go for it! Life is all about taking risks for a good cause.

 

You need to add a sarcasm smiley. I use this one: :madgrin:

 

Buy gas. Heroes don't get out of tight situations, they avoid them. Get stuck in tunnel traffic with a purple battery, the ICE cycling on & off, and a flashing pip and you'll experience a real thrill.

 

When you get the flashing pip fill it up at your regular station. That's what we started doing after the initial several months of shakedown.

 

put fear to bed, buy fuel at your earliest convenience.

 

I would trust the trend shown by the MFD. The apparent drop from the calculation is probably due to the bladder.

 

Hahaha that happened to me a couple weeks ago with 2 pips left and I was sweating a little. That tunnel was steaming hot, too.

 

I thought I'd revisit this post since I now have 8K on my '09, and I've never been able to "use" more than 8.4 gallons between "full" and the "last blinking PIP." So I'm a little envious that you can get more than 400 miles on a "tank" of gas. I was wondering if there's a technical calibration the dealer could perform to my fuel gauge system? Simple math, if I'm always averaging 47-48MPG, seems like I ought to be able to drive more than 325 miles... Based on reading these posts, I've never taken it below the blinking PIP stage, but I sure don't get the range I'd like to.

 

That's approximately the same amount of gas when I fill up. So I think your fuel gauge should be OK.

 

It is not a fuel gauge issue, but a bladder tank issue.
A dealer technician can't solve the problem, but a warm weather can.

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Even in a CA winter with morning temps in the 40's, I've gone as far as 30 miles with a blinking pip ... but not on purpose, rather the next gas station was farther away than I'd hoped. This is averaging mpg's in the mid 50's. I've never gone more than 20 miles via blinking pip since then, and normally refill as soon as it hits one solid pip. Still ... it's nice to know what the limits are.

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I have the same distance limits whether it's summer or winter. I'm used to it, but again, I'm envious of the folks that can go 450+ miles on their bladders. My last PIP starts blinking at only 325 miles, even though I average 47-48 MPG. Boohoo, it's just not fair