Dash MPG different than Actual MPG different t

yes. how many fill ups have you had, and how are you calculating mpg?

 

What i normally do is fill up and then when you're filling up again, divide the current milage by how many gallons i just put in. Keep track of it for a month and then go from there.

 

Wow, that's a big difference. I have a 2013, and The display typically runs about 2.5 mpg higher than calculated (or, about 5-6% - my data is here). From other users here on PC, it seems like 5-10% is the typical gap

When you or your wife fill up, how many gallons do you typically add, and how many dots/pips are on the fuel gauge?

 

It's unfortunately typical for the dash to exaggerate mpg, but not by that much. Most report around 3-8% discrepancy, I think. Mine is consistently high by about 5%.

 

To the OP, dash mpg is always optimistic.

However, your calculated mpg is quite low.

1) Do you have low rolling resistance tires?

2) Are they properly inflated?

 

#1 and 2 address only why basic MPG may be low, not why the dash display and calculated amounts are so widely separated.

I'd ask:
(A) are you resetting the Trip meters at each fillup? If not, then the comparisons so far are meaningless.
(B) are the tires of the correct OEM size?
(C) is there any chance the fuel pump is cheating?

Please report to us the amount of fuel pumped, miles traveled, and displayed MPG for each of the next several fillups. Please give exact meter readings, not rounded estimates from memory.

 

If I take the average of both ranges, say 43.5 and 32.5, that amounts to a 34% error. The error I've settled in on is 7.5%, with over a 100 calculated fill ups, pretty much the usual. All I can think is give it a few more tanks, if it's just variation in how you fill up, it should balance out on the next tank or two.

 

Is the same pump at the gas station used? After the automatic shut off how much gas is added?

 

Could be like us: mostly doing short trips around town these days...I couldn't tell you if we have as big discrepancy as I only value the hand-calc. The dash display is indicative/high.

 

I reset trip A at each fillup too, but mainly for feedback during the tank, to get rough/inaccurate feedback on mpg during the tank, and see how far I've gone. But for calculation, I use the odometer reading at each fillup, record it, subtract value at the last fillup. Invariably this matches the trip A, but you never know: the trip meters can get accidentally reset.

Not sure if your car will work the same, but on ours at shutdown, the odometer displays, for about 30 seconds, regardless of what's displayed when the car's running.

 

Just adding my 2 cents here... I do average about 2.5-3 mpg difference between displayed and calculated milage, usually about 4 - 6% difference as my displayed mpg is 50-53 and calculated mpg averages about 48 plus to 50.

 

Yes, use the odometer to calculate distance traveled instead of relying on trip A meter. The trip A meter is easily reset when resetting the maintenance required light after a service is performed.

Create an account on fuelly.com and input your odometer readings and other information from your receipts and the calculations will be done for you. You'll also get nice graphs, etc

 

go to the gen 2 forum, and answer the questions on the sticky, 'why am i not getting expected mpg'? it sounds like there is something wrong with your car, and those answers will help us narrow it down for you.

 

I have a v and I avg 2 to 3mpg lower then the display.
Fully calculates it easily. I always use it.

For a 13 v3 I avg 46 mostly hwy and flat.
Just moved and now 98% hwy. And lots of hills I'm avg 43. Working on improving it.

If your avg is below 40 you should have it looked at.
Depends on terrain.

When I fill up I round to the next dollar. Ie shuts off at 19.32 I goto 20. 400+ miles with about 9 gallons.

Galaxy?

 

The readout in my 2012 Prius is about 5% high, besed on a few thousand miles of checks. The one in my 2010 MINI also is about 5% high, but the one in my 2016 Corvette is very accurate.

I have little doubt that Toyota and BMW deliberately made the readouts indicate high, to make people think they are getting better mpg. They held it to 5% to avoid bad press and law suits.

Posted via the PriusChat mobile app.

 

When I owned my 2 Gen 3's my lifetime variance was very close to 7% off from dash displayed mpg to calculated. As others have said I have seen as low as 4% all the way up to 9%...

On my Gen 4 it seems to be closer to 5% off. Granted I'm only on my 3rd tank

Pump up the tires for starters. Stop filling up at the first shut off click...

Report back.