35 mpg Prius blues.

You might have learned something if you had read any of the previous posts and tried some of the recommended things. But, no, you kept whining without ever reporting back on any of the suggestions, still haven't in this thread. And we are supposed to feel sorry for you because you won't help yourself?

Yes, I would tell you the same face to face. If you ask for suggestions, then blow them all off without answering a single question, then you expect nothing but contempt. That's your problem, not ours.

Good luck, because you won't be getting any more help from me. :frusty:

 

How embarrassing.

 

You say that you've mentioned the things you've done before, but I can find no indication of that in any of your previous posts. You just mention the bad mileage and the fact that you use air conditioning. There are many suggestions and follow-up questions that you don't answer, but are still interested in having us tell you what to do or at least admit that you must have a lemon. Without further information, it's hard to give you any help. If you had posted the things you posted in your latest post earlier on in the thread (minus the attitude), I think you would have found a much more friendly response.

By the way, we're all very impressed by the picture.

 

Okay guys, let's step back and cool off a bit. There has been some attitude on both sides, but it's time to let it go. I think the OP understands why some of the responders are getting frustrated, and it's easy to see that we have the OP backed into a corner. Time to let him out.

Let's see if we can get this thread back on topic.

Tom

 

Three days a week I drive very short distances through heavy city traffic, lots of red lights not synchronized cabbies cutting me off, etc. Te mileage is dreadful. Fortunately, my long trips twice a week balance the mileage. Traveling 40 minutes to and from work, some interstate driving some suburban rolling hills hypermilng, keeps me in the upper 40's. I gas up in the suburbs and when I reset my mileage I can easily average upper 50's from the suburb back to the city. Short trips, stop and go driving just kill the MPG's. I'm sure winter won't help either.

 

Agreed.

As a public service to everyone I just wanted to point out that not everyone reads every thread (there are probably thousands of posts a day), so "cross-talk" in the threads can often lead to confusion.

So, Izza. You have your tires at 40/38, you're not blasting your A/C, you're driving gently. The one thing I wonder about is the length of your typical trip. You say you have mostly short trips but how short is "short"? Are we talking 1 mile? 5 miles? 20 miles? The first 5 minutes are going to have gas mileage in the 20 MPG - 30 MPG range, especially if you're using the A/C during that time. If most of your trips are only 5-10 minutes, then you're going to have some pretty nasty mileage.

Do you know anyone else with a Prius? Could you get them to drive your car (or you could you drive there car)? This is just try to limit the driver as a variable. If you get good mileage driving their car (or they continue to get bad mileage driving your's), then it's obviously something with the car.

 

Yep, you're right. I get low 50's in the summer (Chicago suburbs, mixed trip length), and mid 40's in the winter (more short trips (< 4 miles) because I'm not biking to work), and when a cold wave hits, like last February (pretty much all month), I'll be in the upper 30's.

But in the end, it's not the mpg that counts, its the gpm (gallons per month). And there I do pretty good by comparison.

 

Pulse and glide is a bit tricky. I tried it but you have to pay attention to the 'arrows' display. The goal is to have all the arrow 'paths' dark, meaning no power going to the wheels, no power from the wheels to the battery (charging). First you get up to speed. A good rule of thumb is not to exceed the 3 mile per second when accelerating, so you may want to stay in the right lane so not to make others behind you upset. Then just barely let off the gas so all those 'paths' are dark. It works best on a slight down hill. What you're doing is coasting, using the cars momentum to maintain speed. If you slow down a bit, repeat the above procedure. It takes a bit of getting used to and you have to be careful to keep an eye on the road and not focus too much on that screen. There's a really good link somewhere on how to get the best mileage on Priuses, or any car for that matter. Maybe someone here can provide the link. It's a bit of a read, but very interesting. I've found that after I fill up the tank, if I drive it like an 'old lady' and keep doing so the rest of the tank until I fill up next, I got right at 55 mpg, even with the a/c on.
It's a different car, and you have to learn to drive it as such. Hang in there and you'll get it... I did And careful on the hyper-miling! The hard core hardly ever use the brakes, even when going around corners LOL WHHEEE!!

Okay, here's a good article...

http://priuschat.com/forums/attachm...pa-mileage-why_dont_i_get_the_epa_mileage.pdf

 

Honestly, I'm concerned about your mileage. If you're driving gently and only getting 42-44 MPG on your long trips, that seems way too low to me. I guess another question is how fast are you going? If you're topping 80 MPH, that might explain it. Otherwise, I think it's really too low. Having trips that are between 2-10 miles should cut into your mileage, but not to the point of the mid-30s.

Have you checked the oil? Overfilled oil could lead to a problem, although I'd be surprised if it were this bad.

The dealers can be a real pain with the tire pressure. I usually just avoid the fight and go to the gas station right next to the dealer (which has free air) and pump up my tires there. Occasionally you'll find a great mechanic at the dealer (and then you should hold onto him like grim death), but a lot of times you're dealing with people who don't know as much about the Prius as a lot of people on this board. I mean, there's a thread on this board about a guy who is rebuilding a totaled Prius in his garage.

I'll say it again: you really shouldn't have to do the "pulse and glide" thing to get yourself up into the mid to high 40s. With no special techniques and moderately short trips (my fiancee is the main one the drives the car and her typical trips are ~3 miles at a time), we're at 46 MPG on this tank.

 

These things were pointed out on page one:
Post #3

Post #6

Post #8

Many of these same things were repeated later by other vigilant posters.

Finally, we have learned tha izza2me is stuck with gas containing 10% ethanol (which costs some mileage), somewhat low pressures, and mostly short trips. Being in South Florida, he is using the AC alot (perfectly understandable.)

The tire pressure issue has been addressed by izza2me IIRC. Hopefully, for the next fill he can try a Shell station or another that is reputed to have "better" gas, just to determine the hit from the gas he's been using (Hess, which has a very poor reputation based on various posters at PC.)

There might still be an alignment issue, but the above might explain much of the problems observed so far, especially in light of the 44 mpg extended highway run. At this point I'm not inclined to point at the car or the driver, but at the typical trip, the tire pressure, the 10% ethanol gas from Hess, and the climate due to AC requirements (and the last will moderate soon enough.)

And I will hedge here and suggest the OP also consider having an alignment done just to make sure the setup on the car is the best it can be. (Again, this should be free in the first 12,000 miles) This is especially important if the car has a tendency to pull left or right. If it pulls either way on the straight and flat then energy is being wasted continuously for driver steering correction as well as increased drag from offset thrust angle. The two will result in more frequent operation of the ICE to maintain speed and battery charge. (Improper alignment will also increase tire wear and result in uneven wear patterns which are even more problematic.)

It's not an inquisition, it's a set of self-help suggestions that can flag problems.

 

izza2me & Shawn,

I belive the alignment is free if done within one year [from the in-service date (not necessarily your delivery date)] and 20,000 miles (not 12,000 miles). Hopefully, izza, your car falls within these limits to allow you the free alignment.

Ken (in Bolton,Ct)

 

The 10% ethanol hurts, but not that much.

I, on the other hand, have had great luck with Hess. I'm not saying that others haven't had problems, but rather that the gas quality within a single company often varies more than the company-to-company variations.

I would be really surprised if alignment killed mileage *that* much. If he had told us that he was in the low 40s, I might tack it up to short trips, 10% ethanol, alignment, tire pressures, A/C usage, and the rest. Being down in the low-to-mid 30s for most of the time makes me wonder.

Something I asked before, but I just want to be certain: you're never using 'B' ("Engine Braking) mode, are you izza2me? You're always in 'D' ("Drive"), right? Other than that, I might worry about a semi-stuck emergency brake cable.

Maybe I'm wrong and this is just what happens to be what happens when a lot of factors combine, but it seems a little fishy to me.

 

Hi Izza,
I'm still curious what is your other car's mileage number on such same short trip conditions.
I posted a question at #20 as follows...

Ken@Japan

 

What do you consider "that" much? He said he got 44 mpg on a highway cruise to the dealer (and that might have included some previous short mileage trips in the average.) Doesn't seem unreasonable that he would see 44 mpg because of 10% ethanol. Others have reported worse hits from it. It's only 1 mpg off the window sticker for the EPA highway mode test.

Cumulative effects have always been the most likely explanation for mileage so far below the norm. I've not attributed this to any one thing, but multiple effects. When izza said he got mid 40's on a toll road (after airing up tires if I understand correctly) it seemed to confirm that his short trips are hammering his mileage. He indicated that he rarely takes trips of more than 10 miles. This is probably the lion's share of the problem, but 10% ethanol isn't helping either, nor was low tire pressure before, hot weather, etc. Alignment is the last of the "low hanging fruit."

After that comes optimizing driving technique to make use of what the Prius does best in these short commutes. Maxing out the AC is a problem as it will result in the ICE running even more often and less efficiently in short commutes. Cooler weather should illustrate a difference if this is correct.

Let's say that an average Prius owner might get 48 mpg on mixed commutes and factor in some effects:
1. Only short trips, 6-10 mpg?
2. Low tire pressure, 2-4 mpg?
3. Heavy AC use, 2-4 mpg?
4. 10% ethanol, 2-4 mpg?
Realizing that the magnitude of the changes shrink as total mileage is lower (so it really should be handled as % reduction from base), it is not hard to imagine dropping into the mid/lo 30's.

 

Shawn, 10% Ethanol will drop mpg by about 3.3% compared to a non-Ethanol blend. Works out to 1 - 2 mpg.
Calculated by google search that says petrol is 150% the energy density of Ethanol.

I'm still waiting for an mpg reading at 55 mph round trip after the engine is warm. I'm with Betelgeuse that a result less than 55 mpg is unexpected unless it is a windy day.

I may be wrong, I thought I read somewhere that max AC pull is 400 watts, or about 1.5 kW of fuel burn. 36 mpg is 1 kWh/mile of fuel consumption. 30 mph city driving, or 2 minutes/mile, is an extra 0.05 kWh or so per mile. Work out to a 5% hit at 30 mpg, or a 7.5% hit at 45 mpg.