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Car Forum / Toyota / Prius / September 2006ECU Flash affects MPG?
There's a growing rumor that the last Engine Control Unit program update has caused the engine to operate more frequently, thus lowering the miles per gallon. I thought I had lost some miles per gallon to the hot weather until I heard this. Anyone have any support for this? Note to Toyota, I bought this vehicle because it looked like a good technological compromise to achieve higher mileage. You've released the Hybrid Highlander, the GX400h, and the Hybrid Camry with minuscule improvements in the mpg versus their gasoline only counterparts. I think you're missing a significant market if this rumor is true and you continue releasing vehicles with only minor mileage improvements. > There's a growing rumor that the last Engine Control Unit program update > has caused the engine to operate more frequently, thus lowering the miles [quoted text clipped - 7 lines] > you're missing a significant market if this rumor is true and you continue > releasing vehicles with only minor mileage improvements. Not sure where you are getting your infomation, but both our cars are fully updated and they are doing equal or better than the last time they were serviced. The older of the 2 averaged 58+ mpg on a trip from MA to NC and back. Second, it's not only about the MPG's but about greatly reduced emissions from the hybrid synergy drive as well that makes the hybrid version a 'better' car than the gas-only version. > There's a growing rumor that the last Engine Control Unit program update > has caused the engine to operate more frequently, thus lowering the miles > per gallon. I thought I had lost some miles per gallon to the hot weather > until I heard this. Anyone have any support for this? I didn't see any change in my fuel economy. > Note to Toyota, I bought this vehicle because it looked like a good > technological compromise to achieve higher mileage. You've released the > Hybrid Highlander, the GX400h, and the Hybrid Camry with minuscule > improvements in the mpg versus their gasoline only counterparts. I think > you're missing a significant market if this rumor is true and you continue > releasing vehicles with only minor mileage improvements. I call them feel-good-hybrids. They are essentially meaningless as far as conservation is concerned. I heard GM as some truly phony hybrids. ... > There's a growing rumor that the last Engine Control Unit program update > has caused the engine to operate more frequently, thus lowering the miles > per gallon. Where did you hear that rumor?! > ... >> There's a growing rumor that the last Engine Control Unit program update >> has caused the engine to operate more frequently, thus lowering the miles >> per gallon. > > Where did you hear that rumor?! From another owner who had his service performed about the same time I did and also had his mpg drop noticeably. That's why I came here, to see if it was only a small sample or a more widespread occurrence. >> ... >>> There's a growing rumor that the last Engine Control Unit program update [quoted text clipped - 5 lines] > and also had his mpg drop noticeably. That's why I came here, to see if > it was only a small sample or a more widespread occurrence. To me, "growing rumour" seems to be an overstatement. >> ... >>> There's a growing rumor that the last Engine Control Unit program update [quoted text clipped - 5 lines] > and also had his mpg drop noticeably. That's why I came here, to see if > it was only a small sample or a more widespread occurrence. After the ECU update, performed in conjunction with my 10K service, I too thought my mileage had been impacted, possibly because I had read this rumor in the Yahoo group. I checked my tire pressure to find they had seriously lowered it (low to mid 30's) in conjunction with the tire rotation. I put it back to 42/40. Over the next few tanks my mileage was as expected given the nature of the trips, wind conditions, etc. I can't honestly attribute my initial and subsequent findings to the ECU update, tire pressure or paranoia arising out of the rumor but I suspect the latter. > There's a growing rumor that the last Engine Control Unit program update > has caused the engine to operate more frequently, thus lowering the > miles per gallon. I thought I had lost some miles per gallon to the hot > weather until I heard this. Anyone have any support for this? Rumor? It's a learned ISC. Some owners have reported slightly lower MPG, while the ECUs "relearn their driving habits" (store some data over time/mileage, to help the tune the vehicle's future performance) after the 50P ECU upgrade. But it will return to normal in a little while. Most owners haven't noticed anything after the upgrades, though. The bigger culprit is that if you live in a hot climate, and are running the AC a lot, that energy comes from somewhere... Your engine will come on more often to help power the AC. Whether you have a Classic (unlikely, as you can't flash the Classic Prius' ECUs) where the engine has to run to belt-drive the AC compressor, or if you have a NHW20 (most likely for you) where the engine will come on whenever the hybrid battery gets low (most likely from powering the electric AC compressor). Just remember that the the governmental fuel economy tests (such as done by the EPA) are done in ideal temperatures (usually in the 70sF) and do not use the heater or AC... >> There's a growing rumor that the last Engine Control Unit program update >> has caused the engine to operate more frequently, thus lowering the [quoted text clipped - 4 lines] > > It's a learned ISC. Please expand the acronym ISC. > Some owners have reported slightly lower MPG, > while the ECUs "relearn their driving habits" (store some data over > time/mileage, to help the tune the vehicle's future performance) after > the 50P ECU upgrade. But it will return to normal in a little while. > Most owners haven't noticed anything after the upgrades, though. Are you saying the Prius' ECU uses more than atmospheric conditions, accelerator pedal position, and the state of charge of the traction battery to determine how to control the engine? Do you have a Toyota document that explains this? > The bigger culprit is that if you live in a hot climate, and are > running the AC a lot, that energy comes from somewhere... Your engine [quoted text clipped - 8 lines] > done by the EPA) are done in ideal temperatures (usually in the 70sF) > and do not use the heater or AC... This is not in regards to any governmental fuel rating. This is in relation to my personal recorded tank fillings and computer readouts. I record both and both are down about 5 mpg. I consider that statistically significant. >> Just remember that the the governmental fuel economy tests (such as >> done by the EPA) are done in ideal temperatures (usually in the 70sF) [quoted text clipped - 4 lines] > record both and both are down about 5 mpg. I consider that statistically > significant. What Michelle is telling us is that the standard does not use heater or A/C, and for that reason we can expect those to have an impact on our economy when we do use them. 5 mpg isn't unusual for A/C when the efficiency is so high initially. It's a matter of fuel used; using a liter of gasoline out of a tank of gas shows up less on a 20 mpg vehicle than t does on a 50 mpg vehicle. Mike >>> Just remember that the the governmental fuel economy tests (such as >>> done by the EPA) are done in ideal temperatures (usually in the 70sF) [quoted text clipped - 13 lines] > > Mike I am not comparing my mpg with the EPA mpg. I am comparing my mpg with my mpg. From the day I drove it off the lot I have had my air conditioning on and set to 75 degrees. So all my comparisons include the loss due to air conditioning. I was getting about 47 mpg. I am now getting about 42 mpg. The two possible explanations are a weather change (it's been what I consider hot) or an ECU flash. I am still monitoring my mpg and now that the weather is back to normal, I am still down about 5 mpg. That's why I requested the experience of others. what dealer, what other person at that dealer, check you air and emergency brake just cause:) could be a good heads up, I run my business on windows 3.1 , never crashed, have never lost data, hate to go backwards but sometimes it's the only direction that work's. >>>> Just remember that the the governmental fuel economy tests (such as >>>> done by the EPA) are done in ideal temperatures (usually in the 70sF) [quoted text clipped - 24 lines] > the weather is back to normal, I am still down about 5 mpg. That's why I > requested the experience of others. > I run my business on windows 3.1 , never crashed, have never lost data, > hate to go backwards but sometimes it's the only direction that work's. I'm not sure what this has to do with the Prius.  SignatureMike Rosenberg <http://macconsult.com/cafepress/> Net Junkie and Mac-themed shirts etc. <http://macconsult.com/cafepress/musings.shtml> Mostly muckraking <http://cafepress.com/comedancing> Ballroom dance-themed shirts & gifts >>>> Just remember that the the governmental fuel economy tests (such as >>>> done by the EPA) are done in ideal temperatures (usually in the 70sF) [quoted text clipped - 24 lines] > the weather is back to normal, I am still down about 5 mpg. That's why I > requested the experience of others. check your tire pressure, the level of the oil, and the emergency brake is fully disengaged, otherwise i have no other suggestions as i did not have your experience with our updated cars... best of luck bro! >>> Just remember that the the governmental fuel economy tests (such as >>> done by the EPA) are done in ideal temperatures (usually in the 70sF) [quoted text clipped - 13 lines] > >Mike As usual, the twit twat twins, Victor/Victoria, uh, Michael/Michelle reply with babble that the OP finds useless. They are the same person? > As usual, the twit twat twins, Victor/Victoria, uh, Michael/Michelle > reply with babble that the OP finds useless. They are the same > person? If you want to see a truly useless person, just look in the mirror you mother f.cking pedophile. SignatureStop Mad Cowboy Disease: Impeach the son of a Bush. >> As usual, the twit twat twins, Victor/Victoria, uh, Michael/Michelle >> reply with babble that the OP finds useless. They are the same >> person? > >If you want to see a truly useless person, just look in the mirror you >mother f.cking pedophile. You queers are all pedophiles: i.e. Michael Jackson. > >>> Just remember that the the governmental fuel economy tests (such as > >>> done by the EPA) are done in ideal temperatures (usually in the 70sF) [quoted text clipped - 17 lines] > reply with babble that the OP finds useless. They are the same > person? How did I get involved in this little flame war? I thought that you just stalked Mr. Pardee and Ms. Steiner across usenet. (The last time I was stalked, the police were involved.) Pretty bad when one cannot even remember who it was that they were stalking. Whomever said that a post had to be useful for the OP? Your post certainly isn't, so why should any others be? oh, do as I say, not as I do. At least my post was useful to someone, other than myself. Mr. Pardee understood the intent of my post, but it was maybe unclear to the OP, maybe because of cultural differences, or that Mr. Pardee is used to my writing style from other Prius discussion forums that he could infer my intent better. <shrug> >> >>> Just remember that the the governmental fuel economy tests (such as >> >>> done by the EPA) are done in ideal temperatures (usually in the 70sF) [quoted text clipped - 32 lines] >used to my writing style from other Prius discussion forums that he >could infer my intent better. <shrug> Let's see now...the OP was obviously NeoPhyte_Rep. Obviously, I was replying to Michael then Michelle. Since your reading comprehension disability questions how you got involved in this little flame war, unless you are a sock for either of those two nyms, you "got" involved by posting to a branch of a topic when no one was talking to you. Pretty bad when one cannot even remember who it was they were replying to...like you...and then tries to muddy the waters with some inane attributions issue. Get a hearing aid for those voices in your head. Hopefully, this is the one and only time I reply to you. :-) > Let's see now...the OP was obviously NeoPhyte_Rep. Obviously, I was > replying to Michael then Michelle. Since your reading comprehension > disability questions how you got involved in this little flame war, > unless you are a sock for either of those two nyms, you "got" > involved by posting to a branch of a topic when no one was talking to > you. Her name is Michelle, and she posted relevant information in this thread. Your "no one was talking to you" is pure baloney; this is a public forum, and anyone can participate. She posted information about EPA mileage testing in response to a message by NeoPhyte_Rep; you asked questions about what she posted, and Michael answered your questions. You then flamed like an a.shole. For the record, mrv@kluge.net (Michelle R. V.) and I are two different people, and Michael Pardee is yet another person. And Michelle R. V. is one of the most knowledgeable people about the Prius and about EPA testing on any of the newsgroups or mailing lists involving the Prius (and probably other hybrid vehicles as well). > Hopefully, this is the one and only time I reply to you. :-) Hopefully, that is the last message you ever post to this newsgroup. SignatureStop Mad Cowboy Disease: Impeach the son of a Bush. > In article <7ubgf2l0qfmp7sgv6n0iicpdmb1c7g27tp@4ax.com>, today@cup.com > Hopefully, that is the last message you ever post to this newsgroup. We can only hope, but don't get your hopes up. >> In article <7ubgf2l0qfmp7sgv6n0iicpdmb1c7g27tp@4ax.com>, today@cup.com >> Hopefully, that is the last message you ever post to this newsgroup. > >We can only hope, but don't get your hopes up. We can only hope Bill kills himself, but he's not bright enough. > We can only hope Bill kills himself, but he's not bright enough. I'm guessing you don't want to buy any of my Prius shirts or bumper stickers, but here's something someone designed specifically for you: http://www.cafepress.com/wantthatshirt/682103?pid=1629 Or maybe you'd prefer it in black: http://www.cafepress.com/wantthatshirt/1054955?pid=1629 Signature<http://designsbymike.biz/macconsultshop.shtml> Mac-themed T-shirts <http://designsbymike.biz/musings.shtml> Mostly muckraking T-shirts <http://designsbymike.biz/prius.shtml> Prius shirts & bumper stickers <http://cafepress.com/comedancing> Ballroom dance-themed shirts & gift >> We can only hope Bill kills himself, but he's not bright enough. > [quoted text clipped - 6 lines] > >http://www.cafepress.com/wantthatshirt/1054955?pid=1629 Sing it, my cheeky bitches... I'm An a.shole by Dennis Leary Folks I'd like to sing a song about the American Dream About me About you About the way our American hearts beat way down in the bottoms of our chests About that special feeling we get in the cockles of our hearts Or maybe below the cockles Maybe in the sub-cockle area Maybe in the liver Maybe in the kidneys Maybe even in the colon We don't know I'm just a regular joe With a regular job I'm your average white Suburbanite slob I like football, and porno, and books about war I've got an average house With a nice hardwood floor My wife, and my job My kids, and my car My feet on my table And a Cuban cigar But sometimes that just ain't enough To keep a man like me interested Oh no, no way, uh uhh No, I gotta go out and have fun At someone else's expense Oh yeah, yeah yeah, yeah yeah yeah I drive really slow In the ultra-fast lane While people behind me are going insane I'm an a.shole (he's an a.shole, what an a.shole) I'm an a.shole (he's an a.shole, such an a.shole) I use public toilets And I piss on the seat I walk around in the summer time sayin', "How about this heat?" I'm an a.shole (he's an a.shole, what an a.shole) I'm an a.shole (he's the worlds biggest a.shole) Sometimes I park in the handicapped spaces While handicapped people Make handicapped faces I'm an a.shole (he's an a.shole, what an a.shole) I'm an a.shole (he's a real f.cking a.shole) Maybe I shouldn't be singin' this song Ranting and raving and carrying on Maybe they're right when they tell me I'm wrong... ... NAAAHHHHH! I'm an a.shole (he's an a.shole, what an a.shole) I'm an a.shole (he's the world's biggest a.shole) You know what I'm gonna do? I'm gonna get myself a 1967 Cadilac El Dorado Convertable Hot pink! With whale skin hub caps An all leather cow interior And big brown baby seal eyes for headlights YEAH! And I'm gonna drive around in that baby At 115 miles per hour Getting one mile per gallon Sucking down Quarter Pounder cheeseburgers from McDonalds in the old-fashioned non-biodegradable Styrofoam containers And when I'm done sucking down those grease-ball burgers I'm gonna wipe my mouth with the American flag And then I'm gonna toss the Styrofoam containers right out the side And there ain't a Goddamn thing anybody can do about it You know why? 'Cause we got the bombs, that's why! Two words: Nuclear Fuckin' Weapons Okay!? Russia, Germany, Romania They can have all the Democracy they want They can have a big Democracy cake walk Right through the middle of Tienemen Square And it won't make a lick of difference Because we got the bombs Okay!? John Wayne's not dead He's frozen! And as soon as we find a cure for cancer We're gonna thaw out "The Duke" And he's gonna be pretty pissed off You know why? Have you ever taken a cold shower? Well, multiply that by 15 million times That's how pissed off "The Duke"'s gonna be I'm gonna get "The Duke" And John Cassavetes And Lee Marvin And Sam Peckinpah And a case of whiskey And drive down to Texas And- (Hey, Hey! You know you really are an a.shole) Why don't you just shut-up and sing the song, pal? You know, the whole time I thought I was that a.shole And it turns out it was him What an a.shole! I'm an a.shole (he's an a.shole, what an a.shole) I'm an a.shole (he's the worlds biggest a.shole) A - SS - HO - LE! Everybody!! A - SS - HO - LE! *dog barking noises* I'm an a.shole and proud of it! http://www.metrolyrics.com/lyrics/5742/Dennis_Leary/I'm_An_Asshole >>> In article <7ubgf2l0qfmp7sgv6n0iicpdmb1c7g27tp@4ax.com>, today@cup.com >>> Hopefully, that is the last message you ever post to this newsgroup. >> >>We can only hope, but don't get your hopes up. > > We can only hope Bill kills himself, but he's not bright enough. LOL. As if you knew anyone in this group. You are an imbecile. >>>> In article <7ubgf2l0qfmp7sgv6n0iicpdmb1c7g27tp@4ax.com>, today@cup.com >>>> Hopefully, that is the last message you ever post to this newsgroup. [quoted text clipped - 4 lines] > >LOL. As if you knew anyone in this group. You are an imbecile. LOL. Clowns like you are all the same. You deserve my contempt. >> Let's see now...the OP was obviously NeoPhyte_Rep. Obviously, I was >> replying to Michael then Michelle. Since your reading comprehension [quoted text clipped - 23 lines] > >Hopefully, that is the last message you ever post to this newsgroup. I hope you hold your breath waiting. > >> Hopefully, this is the one and only time I reply to you. :-) > > > >Hopefully, that is the last message you ever post to this newsgroup. > > I hope you hold your breath waiting. Nah, I know that you're too full of yourself/sh.t (same thing) to refrain from continuing to prove that you really deserve the shirt that Mike recommended to you. Every newsgroup has its a.shole, and you're ours. SignatureStop Mad Cowboy Disease: Impeach the son of a Bush. >> >> Hopefully, this is the one and only time I reply to you. :-) >> > [quoted text clipped - 5 lines] >refrain from continuing to prove that you really deserve the shirt that >Mike recommended to you. Oh, Michelle is one of THOSE who thinks she's blood brothers with a bunch of morons because she owns the same car as they. I bet you were the same kind of idiot who made friends with only Goths because they were the only ones with FEELINGS like you. LOL. >Every newsgroup has its a.shole, and you're ours. a.sholes seem to be on the tip of your tongue a lot, darling. :-) > Please expand the acronym ISC. good question. For some reason, I had ISC stuck in my head. Basically, I meant that the ECU does store information about your driving and external parameters and adjusts accordingly. > Are you saying the Prius' ECU uses more than atmospheric conditions, > accelerator pedal position, and the state of charge of the traction > battery to determine how to control the engine? Do you have a Toyota > document that explains this? Hm, buried in ome of these technical threads is the answer... http://autos.groups.yahoo.com/group/Prius_Technical_Stuff/message/17408 http://autos.groups.yahoo.com/group/Prius_Technical_Stuff/message/17164 http://autos.groups.yahoo.com/group/Prius_Technical_Stuff/message/17454 but unfortunately, I'm having trouble searching back in my archives far enough for when the ECU upgrade was released, or when the Classics had the battery resealing done (where many more people noticed/complained)... > This is not in regards to any governmental fuel rating. This is in Just a reminder about the governmental ratings - they don't take into account heater or AC use, which both will lower fuel efficiency. > relation to my personal recorded tank fillings and computer readouts. I > record both and both are down about 5 mpg. I consider that > statistically significant. other thoughts: 1. It's summer in the northern hemisphere, and winter in the southern hemisphere. Temperatures are more extreme than a few months ago, which means that the gasoline engine will be running more to provide for the added climate control for these extremes. 2. did any change in fuel occur since your upgrade? summer/winter blend? addition of ethanol? 3. did you have anything else done at the same time as the upgrade? dealers are notorius for using the wrong grade of oil, oil overfill, and not setting tire pressures correctly. 4. have you checked your parking/emergency brake? sometimes they do get a little sticky. 5. have you hit a pothole or curb, that may have knocked your alignment out? >> Please expand the acronym ISC. > [quoted text clipped - 39 lines] > 5. have you hit a pothole or curb, that may have knocked your alignment > out? 1. As I said I first suspected more use of the air conditioning, but that is back to normal and the mileage isn't. 2. I don't remember if the service occurred at the same time as the seasonal mixture change, but that would affect more than my Prius, which is why I came here for the experience of others. 3. I think I'm going to research these possibilities deeper. I haven't been in the habit of checking the dealer's employee's work, but maybe I should be more careful. 4. I'll dig into this one, too. 5. No potholes of significance. Lot's of small bumps since there's a growing lack of road maintenance to save budget. Thanks for your suggestions. > > It's a learned ISC. > > Please expand the acronym ISC. Found it. ISC = idle speed control. It was stuck in my head from reading the TSBs for the Highlander Hybrid: http://www.alldata.com/tsb/Toyota/1141027200000_1141718400000_EG026R-05/index.html http://www.alldata.com/tsb/Toyota/1155711600000_1156489200000_EG050-06/index.html where if the 12v battery is disconnected or drops below 7 volts, there is a procedure to reinitialize the idle speed control. to quote those TSBs: "If this procedure is NOT performed, the following customer complaints may occur: Engine runs too long or more frequently than normal Reduced fuel economy Transmission gear "clatter" noise at idle is more pronounced" >>> It's a learned ISC. >> Please expand the acronym ISC. [quoted text clipped - 14 lines] > Reduced fuel economy > Transmission gear "clatter" noise at idle is more pronounced" Thanks. I'll see what the service manager has to say about this information. I saw no indication that the battery had been disconnected, but you never know. |
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