My 2018 Prius Three is draining gas FAST

Hi

Depends on how deep you want to go. There are some L-O-N-G explanatory YouTubes by WeberAuto (like 1½ hr) showing the intricacies of the "gearbox" and the High Voltage systems - fascinated me, but you mightn't be into the technical details like I am.

There are other YouTubes by Prius owners on various aspects of driving. One who did quite a few, but none recently is " jettlash1000 " - call up his name in the YouTube search - and search for PRIUS in the search from his page.

Another PriusChat member, Jimmipri did a number of videos on his PRIUS including a conversion for camping - his YouTube channel is " Wonderful Wandering Topics ".

One thing you might like to do is set the ECO DIARY - it shows the avg MPG for each day (and you can scroll down if you want more than 4 days - it's not as "active" as most other screens - as it only changes once a day!!


If you're into reading - there is the Manual. I found it was good bedtime reading - a few pages and I'd doze off. But did eventually read most of it.

Tony Schaefer has done some videos on "hypermiling" worth watching - might help with MPG:
Videos about Hypermiling | PriusChat

 

Please don't take this as negativity. But I'm still not sure you are doing what IMO you need to do. Which is hand calculate your MPG based on total miles driven between fill ups-not trips, and amount of gasoline added at the pump. Going by how many gallons of gasoline the pump say's has been added at fill up...and how many miles you've driven since your last fill up.

At least until you get this nailed down, you kind of want to ignore any average MPG the Prius is telling you, you are averaging. Also Distance to Empty or Range, won't really help you calculate your MPG. That's really just a tool to help you NOT run out of gasoline.

This means resetting your trip A odometer, when you pull in to fill up. Fill up to when the pump shuts off. Do not top off. When you pull out of the gas station, trip A should start counting exactly how many miles you are driving from that exact point.

Then drive until you feel you want to fill up again. BUT...when pulling in to refill...note how many miles the trip A meter say's you have driven since your last fill. Write this number down, because once you fill again, you will want to reset your trip A meter again.
Do the same process when filling...getting a receipt (most receipts tell you how many gallons were pumped into your tank ) or noting on the pump, how many gallons of gasoline has been added to the tank.

Take the total amount of miles you've driven since the last fill up, and divide it by how many gallons of gasoline you've added. That gives you a Non-Prius computer, hand calculated MPG average since your last fill up.
This is IMO the most accurate way to really determine what your MPG is averaging between fill ups.

If this is what you are already doing? Accept my apologies before hand. Do not want to sound negative. But IMO, if the problem is being advanced as abnormal fuel usage...poor gas mileage. Then this can't be determined by things like " A bar, or pip disappeared on the fuel gauge while the vehicle was in EV mode".

The only way to determine if your Prius is "Draining Gas Fast"....is to absolutely know, and figure out what your MPG actually is.

 

If the trip meters are tripping you up: just record the odometer when refilling, and the gallons you put in. Do the same thing next time, and subtract the old odometer reading from the latest. The remainder is the miles you travelled for that tank. Divide that number by the gallons; that is the miles per gallon.

Repeat, always recording the odometer and the gallons added. The odometer is the ONE value that cannot be messed up.

Does 4th gen still display odometer when the car's shut off, for about a minute? This is regardless of any of the display settings.

 

Yes, AFAIK. Odometer mile will also display when you enter the car before you START..

 

I’m up in Fairfield.

If your up for a drive, I could spend some time showing you the ropes .

We also do meet ups:

Possible Monthly install meets. Bay Area-Fremont

Good luck and keep us posted .

 

As you open the door, it shows.

 

I'm thinking that Chime must be topping up, at least some of the time, maybe really overfilling it which could somehow contribute to the loss of gas while the trip computer shows good mileage.

The fuel tank capacity of the 2018 Prius is 11.3 gallons. Chime put in nearly 10.9 gallons. That means that Chime either drained the tank to a very low level, over filled it or the pump at the 7-11 is inaccurate. So, I agree, do not top off after the pump automatically shuts. (Although I must say that this doesn't explain why the fuel gauge seemed to drop quickly. The mystery continues.)

 

Absolutely true.
For me, I always found it easier (more convenient) to simply reset the trip A meter, from fill to fill. BUT...whatever is easier.
You simply want to know exactly how many miles you've driven since the last refill. And simply going by the main odometer is 100% valid. I just always found it easier, to simply reset the trip A meter when I pulled in to fill up.

 

It is confusing what she means by "Previous:" but my guess is that odometer reading of 927.2 miles and "Current Fuel-UP of 10.895 gal are the record taken today (9-11-18). If you believe that to be true, and if this is her 4th fill-ups since she purchased the car. Her previous fill-ups from her bank record shows 1st $15.65, 2nd $35.67, 3rd $21.17. Assuming gas price of ~$3.50/gal in her area, the amount of gas for those 3 fill-ups are 4.5gal, 10.2gal, 6.0gal, totaling ~20 gal. If we ignore the 1st fill-up of $15.65 as top-up of the tank, then 10.2+6.0+10.9=27.1gal of gas have been used for at most total of 927.2miles or 34.3mpg. If the car had been driven some distance before her 1st top-up, the actual distance driven is shorter than odometer reading of 927, making actual mpg lower than 34.3mpg.

From those numbers, car's average mpg is substantially lower than what the display is showing and IMHO too low for a brand new Gen4 Prius under normal driving condition OP has described.

One possibility as @royrose has suggested is that gas pump is skimming some unpumped amount of gas and adding into the bill. It is strange that she put almost 11gal of gas yet "Remaining mile" is still showing 10. With my experience for PRIME, even when remaining mile reaches to 0, I could pump less than 10 gal, meaning there are still more than gal of gas left in the tank.

 

Just wait till she fills up tonight - I think we worked out that the first fills weren't well recorded - we'll see what today's fill shows. I suspect it'll show there isn't a problem at all.

 

I think she said she just filled today and her car is now at dealer for tinting. It will be another few weeks before we have conclusive report on mpg.

 

By Previous, she meant that's what she wrote down right before her current fuel up. She also said at the last fuel up, she reset Trip A (to 0). The "Remaining Miles" was displaying 10 before she got this fill. After this fill (with full tank), it showed 497 miles.

 

Hi - with today's fill - did you take an odometer reading?

 

Yes. The odometer reading right before the fill was 927.2 Miles.

What's obvious to me is not always obvious to others. Maybe it takes a "she" to understand her. (reference)

 

She actually said that was "Previous" reading.


She said she's going to "... drive the car for another 2-3 weeks, keep the receipts and track my miles per trips inbetween." And she's opened up a Fuelly Account - which will keep definitive data.

 

i spose in a week or so we'll get the same vague response

 

I do both, odometer and Trip A: belts and braces. Trip A might be accidentally reset, or a battery failure could reset it. Or someone using your car decides to top you up*. So many scenarios can mess it up, so yeah I use trip A, but just for a check. At fill up I note the odometer reading, trip A (then reset it), and the liters per 100 km's the car claims I did. The latter just to track the "error" percent.

* When this happens, as long as they hang onto the gas receipt, you're good. Just wait till the next fillup, lump it in. This is where odometer readings shine.

 

I don't have too much of a dog in this hunt. If it's easier for anyone just to use the odometer, and they are willing to do the 1 step subtraction between fill ups? Then go for it.

The pain for me? Is I live in Oregon, which archaically does not allow "Self Serve" gasoline. I fight a never ending battle trying to NOT have attendants top it off while I'm not looking.
Despite stickers all over the pump saying "Vapor Recovery System Do Not Top Off" and even evidently laws concerning NOT topping off...attendants still do it.

If I pull up and ask them to NOT top it off? I ALWAYS get this dirty look and usually an exclamation that they NEVER top it off.
If I pull up and say nothing? Most of the time they will top it off.

I use to be a proponent of Oregon's non-self service laws. But I've changed. I really wish Oregon would allow me to pump my own gasoline.

Just this last fill up, I was upset because I think the pump shut off at 20-40 cents away from an even dollar amount. I saw the kid going to "bump it up"....I was tired and thought...OK this once...I'll let him even the total. BUT then I watch as he "accidentally" goes over the next dollar amount. He then proceeded to pump in gas up to the NEXT full dollar amount.

I think it's worse for me, because I usually pay cash, and I think these guys don't want to make change.

But in any case, in Oregon, you have to be very aggressive about making sure your gasoline is ONLY pumped until the pump shuts off.

I'm going to try making a sticker that says...."Do Not Top Off".....and put it on the inside of my gas cover. Maybe a passive, non-accusatory sticker will help?

 

i use trip a for trips and trip b for tanks. simple enough, even for my puny brain.

 

Our "city", Coquitlam, is one of the last bastion against self-serve. Luckily every adjacent city, and virtually all of Greater Van, is self-serve. We moved here nearly 30 years ago, and filled the tank in our unenlightened city maybe twice that I can recall.

One thing, vagaries in fill up technique always even out, cannot persist over multiple tanks: no matter if it's underfilled, overfilled, two or three tanks and it all balances out.