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Discussion Starter #1
Just thought I would pass along a few notes. Maybe this has been covered.

1. Per my conversation with Toyota "Executive Customer Service" ( :roll: ), I am informed that putting 91 octane into the Prius is "a waste of money." The engine compression is high enough that 87 octane is perfect for the car.

2. I got to this point because there was a sudden drop off in the MPG;

3. I got to "Executive Customer Service" because I had a tantrum.

Not to be a party-pooper - but, I have had enough bad experience with Toyota to warrant the "I will never do business with them again" award. This is because of their refusal to address the MPG problem (the drop-off, not the actual milage per gallon), the engine knocking and the power loos that I have had.

For those interested, out here in California, it's been mighty hot. The vent at the right of the rear seat is constantly sucking air to cool whatever it cools. When this is happening, the car bogs out. It got such that I had to ditch the car on the side of the road once.

So, after my local dealer told me that it was my imagination, the next dealer told me that it was illegal for them to fix it. (ROTFLMAO. I'm a lawyer. And, I really wasn't laughing when I heard that.) So, I had a tantrum (a lawyer tantrum with lots of expletives) and "Executive Customer Service" intervened. That was a week ago and I haven't heard anything since.

So, whatever. I'll stop trashing Toyota now. I'm sure it makes some people uncomfortable. Sorry.

At least when I get rear-ended, I'll have the right gas in the car.

Tony :)
 

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woodstock said:
1. Per my conversation with Toyota "Executive Customer Service" ( :roll: ), I am informed that putting 91 octane into the Prius is "a waste of money." The engine compression is high enough that 87 octane is perfect for the car.
Duh. Doesn't everyone know this? By the way, it's higher compresison that requires higher octane fuel to resist preignition. Your Prius doesn't require premium because the compression ratio is low enough to not need it. That's a property of Miller cycle engines, unequal compression and expansion ratios (lower compression ratio than expansion ratio).

Several other people have reported the same problem you're experiencing over on Priuschat.com. In each case the problem occurred during hot weather. Not all Priuses are affected though as many owners in Phoenix and Las Vegas have not had similar problems. Seems to be a battery overheating problem, but I don't understand why it only affects some cars. Maybe different versions of software, or a bad batch of components. Or maybe your kid has been shoving chewing gum down the battery vent.

Q. What do you get when you cross a lawyer with a pig?
A. Nothing. There are some things a pig just won't do.
 

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priusenvy said:
woodstock said:
1. Per my conversation with Toyota "Executive Customer Service" ( :roll: ), I am informed that putting 91 octane into the Prius is "a waste of money." The engine compression is high enough that 87 octane is perfect for the car.
Duh. Doesn't everyone know this? By the way, it's higher compresison that requires higher octane fuel to resist preignition. Your Prius doesn't require premium because the compression ratio is low enough to not need it. That's a property of Miller cycle engines, unequal compression and expansion ratios (lower compression ratio than expansion ratio).
Strange that you and Toyota US say this. My EU handbook, and stickers by the gas tank filler says to use 95 Octane, our "Super" mix.
 

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Victor said:
Strange that you and Toyota US say this. My EU handbook, and stickers by the gas tank filler says to use 95 Octane, our "Super" mix.
Not really.

In the US we use pump octane (R+M/2). In Europe you use RMON. Your 95 octane "EuroSuper" is about the same as our 89 octane Mid-grade. Your 98 octane "SuperPlus" is about the same as our 91 octane Premium. Typical pump octanes in the US are 87 for regular unleaded, 89 for mid-grade, and 91 for premium. I've seen regular as low as 85 octane and premium as high as 93 octane in the US.
 

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Ok that accounts for it. You dont get 100 Octane then right?
 

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100 octane is only available at race tracks for high performance engines and costs $6.00 a gallon, instead of $2.50 that 93 octane costs.The car I race gets 4-5 mpg at the track and at $6/gallon, it gets expensive.
 

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woodstock said:
So, after my local dealer told me that it was my imagination, the next dealer told me that it was illegal for them to fix it.
"Illegal"? What did they say was the problem?

We can only suggest going to another dealer. Most of our Prii are not fcuked up like that. Yours should be fixable.
 

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woodstock said:
For those interested, out here in California, it's been mighty hot. The vent at the right of the rear seat is constantly sucking air to cool whatever it cools. When this is happening, the car bogs out. It got such that I had to ditch the car on the side of the road once.
I was under the impression that the vent on the side of the car was for exhaust, not intake. Doesn't it draw air from the cabin to cool/vent the battery(s)?
It's been over 100 here with 95% humidity for a week or so. I've had no problems other than heavy sweat.
 

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He said right side of rear seat. That is the intake for the cooling airflow for the traction (HV) battery.

Your traction battery is behind your rear seat, and operates optimumly about the same temperature we like, about 72 degrees. It doesn't like really hot temperatures, so if you do, and your cabin is hot and remains hot, the car will not use the battery as much as possible to prevent overheating it.

If you read your owner's manual, it states to use 87 octane. Using higher octane is indeed a waste of money and may indeed reduce performance. So move back to 87 octane, save your wallet some pain, and see how the car performs then.
Also, try to keep the cabin temperature under 90 degrees, better yet, under 80 degrees. Your performance should improve then.

For the first 5 minutes, the mileage of the car will be low compared to EPA. This is because the car sets itself up to quickly warm the ICE, O2 sensor, and the catalytic converter. After the 5 minute mark, assuming the battery SOC is at 60%, your mileage should shoot up to mid 40's to upper 50's depending on travel speed and traffic.
So if all you do is really short trips, say less than 10 miles, with an hour between trips, you will indeed get 35 miles per gallon. Even this is much better than other cars in the same driving condition.
 

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Discussion Starter #12
Thanks for that feedback, it's helpful. Frankly, I get too busy to pay a lot of attention to things I should - like my car.

Richard Schumacher:

"Illegal"? What did they say was the problem?
The service manager at Hamer Toyota in Mission Hills, CA said "It is against the law for me to do anything with the car without duplicating the problem." The conversation went such that it was up to me to duplicate the problem, then call sometime thereafter. (??) So, we got into a conversation regarding the respective consumer protection laws (to which I think he was referring) and it's always downhill from there. He never offered to have the car in for a diagnostic eval.

The problem is that these cars obviously take some effort to understand and I wonder if the dealerships feel like its a statistical white elephant.

I like the car.

(BTW - My comments regarding being a lawyer were self-depricating. On the other hand, I don't appreciate being referred to a "khazer" out of the gate, but I'm not going to get into a board war over it.)

In any event, I obviously need to pay more attention to what I am doing with the vehicle.

DanMan's comments make perfect sense. I drive a mere four miles to the office each day and there is about six hours between those trips. Therefore, the respective milage makes sense. I do get better milage on longer trips, regardless of the driving conditions.

Frankly, I'm very satisfied with the milage. I was just concerned because of the apparent sudden drop off.

FYI - I am going to take the synthetic oil out of the car. The decrease in the milage seemed to correlate with that oil change. I'll report back either way.

Thanks again.

Tony
 

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I also noticed a marked decrease in mpg when I changed to synthic oil. I can't believe there is a correlation though. I'm thinking of waiting several thousad miles before changing back to dino.
 

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2far4gas said:
100 octane is only available at race tracks for high performance engines and costs $6.00 a gallon, instead of $2.50 that 93 octane costs.The car I race gets 4-5 mpg at the track and at $6/gallon, it gets expensive.
You can get 100 octane at small airports. But don't!
 

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Hmm. Most have reported no change or better mileage with synthetic, but I haven't heard worse.
Be sure the car wasn't overfilled. That's a common practice as dealers insist on putting in 3.9 - 4 quarts. If you get every single bit of oil out, then it is supposed to be 3.9 quarts, but usually it takes less to get to the full mark, like 3.5 quarts. Some have felt that MPG suffers a bit with oil over the full mark.
Oil a little over full shouldn't cause any harm though, that's how they get shipped to the dealers.
 

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Leave the synthetic in, there is no way it could cause the mileage to drop. As just said, check the level and make sure it is not over filled. Most oil change places fail to allow enough time for all the old oil to drain, and then over fill.

I don't think the manager really choose his words correctly - when he said illegal I would bet he ment that Toyota policy does not want them messing with a car that another dealer had started working with. I had a similar experience with a BMW dealer that initially told me he would not work on my car as I did not buy it from his showroom. I explained I bought it used from an individual - he said he would make an exception, but only because I did not buy it from a different dealer.
 

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Tony,
There are a lot of factors that most service managers will not be in a postion to address that may be impacting your mileage and account for the recent decrease that you've noted.

As others have suggested be sure to check the oil level...if they just dumped in a full 4 quarts you could, indeed, be over filled. I would NOT dump the synthetic. If anything it should be improving your mileage if at the proper level.

Second, go out, today, and check your tire pressures. Often when they do oil changes they adjust tire pressures for you as part of the 'service'. If they found the pressures to be high they probably decreased the pressure to factory specs. The problem is that the tires would have been hot and once they cooled down the pressure would be too low.

I strongly encourage you to increase the (cold) pressure to the 42f/40r level and see if that doesn't have a positive impact. If you find the ride too harsh you can always dial it back later.

It has been hot, as you mentioned. What do you have your AC set at? If you have it set low (like less than 75 degrees) and only drive about 4 miles each way that's going to majorly impact your mileage. Over a longer drive such A/C use will have a relatively minor impact, but on short trips it'll be a killer. Case in point, I usually get around 58-60mpg in summer driving. Yesterday with a very hot car, stop & go driving I had 2 sequential 5 minute bars below 15mpg and the third was only around 35mpg...at about 4 miles into the trip!! But, by the end of the 15 mile trip I'd gotten the mileage back up to around 60.3. I'd started the day at 60.5. I had my family of 5 in the car on roads with top speeds of 45mph and low speed of 35mph.

I would encourage you to do yourself a favor that should put your mind at ease. Take the car for a nice casual 50 or 100 mile drive through the country this weekend. Set the AC at a comfortable level (maybe 77 or 78 degrees), pick a road without a lot of traffic or frequent stops and an average speed of around 45mph. Start with a full tank of gas or reset the mpg calculator. Check the tire pressures and oil level as above. And have a good time. Betcha a nickle you get over 50mpg.

--evan

woodstock said:
Thanks for that feedback, it's helpful. Frankly, I get too busy to pay a lot of attention to things I should - like my car.

Richard Schumacher:

"Illegal"? What did they say was the problem?
The service manager at Hamer Toyota in Mission Hills, CA said "It is against the law for me to do anything with the car without duplicating the problem." The conversation went such that it was up to me to duplicate the problem, then call sometime thereafter. (??) So, we got into a conversation regarding the respective consumer protection laws (to which I think he was referring) and it's always downhill from there. He never offered to have the car in for a diagnostic eval.

The problem is that these cars obviously take some effort to understand and I wonder if the dealerships feel like its a statistical white elephant.

I like the car.

(BTW - My comments regarding being a lawyer were self-depricating. On the other hand, I don't appreciate being referred to a "khazer" out of the gate, but I'm not going to get into a board war over it.)

In any event, I obviously need to pay more attention to what I am doing with the vehicle.

DanMan's comments make perfect sense. I drive a mere four miles to the office each day and there is about six hours between those trips. Therefore, the respective milage makes sense. I do get better milage on longer trips, regardless of the driving conditions.

Frankly, I'm very satisfied with the milage. I was just concerned because of the apparent sudden drop off.

FYI - I am going to take the synthetic oil out of the car. The decrease in the milage seemed to correlate with that oil change. I'll report back either way.

Thanks again.

Tony
 

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DanMan32 said:
He said right side of rear seat. That is the intake for the cooling airflow for the traction (HV) battery.

Your traction battery is behind your rear seat, and operates optimumly about the same temperature we like, about 72 degrees. It doesn't like really hot temperatures, so if you do, and your cabin is hot and remains hot, the car will not use the battery as much as possible to prevent overheating it.

<snip>
So on hot days, it would be best to run the AC set to recirculate, rather than try to get by with just open windows?
 

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Sid said:
DanMan32 said:
He said right side of rear seat. That is the intake for the cooling airflow for the traction (HV) battery.

Your traction battery is behind your rear seat, and operates optimumly about the same temperature we like, about 72 degrees. It doesn't like really hot temperatures, so if you do, and your cabin is hot and remains hot, the car will not use the battery as much as possible to prevent overheating it.

<snip>
So on hot days, it would be best to run the AC set to recirculate, rather than try to get by with just open windows?
I usually run with windows down for a bit to get the cabin down to the ambient air temperture. But yea, once you hit that point it's probably a bit more beneficial to run the A/C for battery cooling purposes...and more comfortable to boot. Not necessarily on recirculate though....let the car decide.
 
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