Gas gage Question

It's generally though the discrepancy between actual fuel left and displayed fuel left is to keep us from running out of fuel. Once you get a handle on it, you can pretty much use your own best judgment for when to fuel up.

 

With my previous Priuses ('04 and '11) with 11.9 gallon tanks, I used the "rule of 10" -- multiply current average MPG x 10 to determine when to re-fuel. The rationale was that (a) the current fuel consumption may be more than that tank's average to date, (b) the displayed MPG runs about 4% optimistic, and for the '04 (c) the bladder made determining "full" rather difficult.

With the smaller, 10.8 gallon tank in the PIP, I'd go with a "rule of 9." But with the PIP, the impact of EV mode may really munge any assumptions based on tank-to-date consumption. I'm still at the embryo stage of understanding my PIP's dino-fueling appetite, so take this with a grain of salt.

 

fill up when or before the last pip is blinking. the remainder is for emergency only.

 

I always fill up with two bars. I figure it's one or two more stops at a gas station a YEAR.

 

When the PiP's last bar starts to blink AND the "miles left" indicator which can you can display instead of the odometer shows ZERO, many PIPers here, including myself, have reported driving the car for another 20+actual road miles. Caveat emptor: just because this is doable is not a good reason for it to become habitual.

 

This will be my plan. I start getting nervous at this point on my other cars.

 

I remember that this was the subject of endless debate when the Prius Gen 2 came out. Many spirited discussions on the old Yahoo boards.

I wouldn't quibble with filling at 1 bar, 2 bars, or 9 x average MPG. They all should work and not result in a call for roadside service.

 

You can easily travel another 50 miles after the DTE goes to zero.

 

While certainly true in Prii (I've taken my 65 miles beyond DTE=0, and do believe it will go about 100 mi, similar to Bob Wilson's fuel range tests), I found that this is not universally true among all car models. My household's new Forester (replacing a previous Subaru) also has a DTE display, but its Zero point is about where the tank actually runs dry.

Yes, I did run it dry, in an intentional range test. I'd actually wimped out and pulled into a station to refuel, because the next stretch of road exceeded the range of my backup fuel can. The Forester sputtered to a stop seconds after I pulled up to the pump. While its DTE display is rounded to 10 mile increments, and was blanked out shortly after it dropped to 30 miles, the fuel starvation point was very close to where the display would have dropped to Zero. And the refill was less than 1% off the car's advertised tank capacity.

Maybe this different display behavior in other cars contributes to many Prius newbies being concerned about getting close to DTE=0 in Prii.

 

Does anyone know how to recalibrate this. If I fill up at 0 with mu 2012 plugin I can barely squeeze in 8.5 Gallons. I drove an extra hundred miles after it hit zero and didn't even put in 9.5gallons. It is really frustrating because the car thinks my range is only about 460 miles on a tank. The other cars in my family that aren't hybrids get much higher ranges than this. I can understand a reserve but a 2-2.5 gallon reserve is insane. Fully charged on a full tank i barely read over 470mile range.

 

After Distance to empty goes to zero, does it still continue to count? Like -1, -2, -3 and so on?

I ask because I came from motorcycle world and some motorcycle gauge does count the negative.

 

If the MTE calculation is anything like the EV range calculation, it depends on your recent driving history.

 

It is calculating fine. 470miles / 8.4 gallons = ~56mpg. What I want is my gas gage to not think the car is empty with over 2 gallons left in the tank.

 

The car maker equivalent of Tech Support doesn't want to deal with the flood of angry customer calls that will result if no safety margin is built in.

 

One way to obtain a much more accurate estimate of fuel remaining is to purchase a Scanguage II and then calibrate its fuel consumption estimates when you refuel. I have been doing that and find its "gallons remaining" estimate to be accurate to about 1/10 of a gallon. The low fuel beep and onset of the blinking pip in my Gen III hatchback occurs with more than two gallons remaining according to ny records, but pip may be slightly different .

 

That is a good plan.

There are lots of threads on this forum, people strategizing how to stretch a tank. There's no point to it, other than risking a long walk, and/or hybrid battery damage. The latter can happen if you run dry: the car will allow you to run EV, and run the battery down to point of no return.

 

You sure about that? Why would the computer programming that protects the traction battery suddenly stop protecting simply because the ICE stops due to no fuel (or for any reason)? That doesn't seem to comport with anyone's reports that I recall after 11 years on Prii fora.

 

^ I'm thinking the same thing, that it's poor engineering to allow this. But there's been a few accounts here, attesting to the hybrid battery being seriously depleted after the car ran dry. Here's the thing: if there's a very simple behaviour change that can avoid a possible horror story, however remote, I'm all for it.

This involves a second gen Prius, fwiw. Also, it's inconclusive. Personally, I'd rather not flirt with disaster

Has running out of gas killed my hybrid battery? | PriusChat