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low mileage on start-up?

4K views 7 replies 7 participants last post by  gamatt 
#1 ·
Hi
Had it a week and a half now & have been surprised that the 1st couple of miles [all down-hill] register such poor mileage on the consumption screen. Other times coasting downhill the level goes up toward a hundred, but not right away. The first 5 minutes graph has always been just around 25, when later on in the drive with coasting, the graph goes higher. Avg mileage spot on the screen, about 47, which the salesman says is low because I'm drivng too fast. The mileage for startup is low whether it's in the 30's out or 40's. Is there hope of that improving after a while? [Only at 400+ miles now]
Thanks
Greg
04 white #6
 
#2 ·
If I'm reading your question correctly, you're wondering why the first few minutes of your drive register low MPG?

The Prius has a "warm-up" period of a few minutes. The ICE kicks in almost immediately, even in reverse, I've found, in the first few minutes of driving. (Hence, Toyota and most users recommend combining trips and not going on many short start-and-stop trips - it defeats the purpose of owning a hybrid, since you're never really "warming up" enough to run on just the electric motor.)

I'm sure there are folks who will be able to give you a more scientific explanation, but just know that you won't get your best fuel economy until the car's been running a few minutes.

And it does get better with time. Each tankful has been getting better and better for me, and I'm only at 1200 miles. I read somewhere that you really shouldn't even focus on your mileage that much until you hit about 6,000 - that's apparently when the car starts hitting its stride.
 
#4 ·
gamatt said:
Had it a week and a half now & have been surprised that the 1st couple of miles [all down-hill] register such poor mileage on the consumption screen.
I've noticed this as well. I live at the top of a hill and the first part of my drive in the morning is 2 blocks down a steep hill.

My mileage for the first bar is rarely over 25 MPG. The temps here are around 60 in the morning.

I am noticing in the evening during my commute home when it's about 80 sometimes that the first bar will be about 35 or 40, so "warm-up" can definitely be helped by warmer weather.

Short drives will always reduce your overall mileage. My commute is 4 miles ... so I only get about 44 for that trip and have been averaging about 47-48 when I mix in my other longer driving per tank. I've got 2K miles at the moment.
 
#5 ·
LOWEST EMISSIONS is the primary goal of Prius, not HIGHEST MPG.

Heat is needed to make the chemical reaction in the catalytic-converter work. So, the engine is run to create that heat, which means some gas is actually sacrificed for the sake of cleansing exhaust.

As a consequence of that design choice, you will notice reduced MPG whenever the engine is still cold.

In other words, avoid short trips. Take advantage of a warm engine.
 
#6 ·
I am recording the run log in every time from March 18, 2003.
I have run the various distance from short to long distance at 2023 times since then.
These are the average value classified with mileage.
These show the influence of the mpg for 5 minutes of the beginning.

short-dIstance........42.00MPG....3 miles or less at 897 times
mIddle-dIstance......51.68MPG....3 to 10 mIles at 550 times
long-distance ..........61.50MPG....10 miles or more at 576 times

The ratio of the total mileage of the long-distance classification to the whole total mileage is 80%.

Under a traffic rule of Japan, usually, the limits of a running speed are 31mph or less on many ways, are 37.5mph on the national way of the suburbs, and are 62.5mph on a highway.
I run at the speed of 40mph or less, and make many the run of a motor drive.
And I run at around 53mph at the slow lane on a highway.
Prius runs a motor drive with an accelerator work very easily. 2004 models are still easier and adding to coasting.
The EV button is not required.

_______________________
USK Bordeaux mica 2001
22,140.08 miles / 379.05 gallons = 58.4 mpg 3/29/04
 
#7 ·
Every car gets terribly bad gas mileage when its engine is cold, including the Prius, because the engine needs to be hot to operate properly, even regardless of pollution issues. Oil viscosity, among other things, is much higher when the engine is cold and is responsible for more friction.

What the Prius is trying to tell you when it displays the 5-min consumption bars is : "What the hell do you need me for a 3 mile trip ? You'd better walk or take your bicycle instead ! That would be better for your health too..."

It's not only a car, it's a learning device. :wink:
 
#8 ·
Thanks for all the replies

Hi
Had it 2 weeks today,always trying for the higher mpg, but have resigned, thanks to hearing from all of you, that the 1st 5 minutes will always be low -- 25 mpg or so. SUVs should be so lucky. Somewhere somebody got the idea I'm doing lots of short trips. Almost never; I just look at the first 5 miles and see low mpg. Now I understand why. Thanks
Greg
04 white #6
 
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