I've been noticing some weird MPG readings in my Prius and my MPG has been really low (38.6). When I accelerate, not too fast, I still get 9-15 MPG readings that I don't remember getting before. Also, sometimes when I am coasting, the MPG doesn't go to 99.9 all the time, somtimes i get 70-90. This is weird because it didn't use to do this. I'm doing less freeway driving now, but the only time i see even relatively good MPG is when I get up to speed, and even then they aren't as high as usual. Anyone know what might be going on? Thanks.
Hhmmm? :roll: Haven't heard from any of my customers on this. Hope its not a big problem and I will be keeping up on this thread to see what others say.
<div class='quotetop'>QUOTE(exces6\";p=\"68915)</div> "Bad gas" sometimes does that to me. Less energy in it, somehow... Engine may not be warm enough, if the outside temp is cold enough. Some days when I finish the 15-20 minute drive to work, I can cruise at 25MPH in stealth through the parking lot, and sometimes I can't...
I've never seen coasting not hit 99.9, I must say. I know bad gas can also mess up the fuel sensor, as it happened to my parents a few months ago. I think it was a high sulfur content that screwed things up, so the gas wouldn't simply have to perform worse. Just a possibility, however.
1st Did you have to have the ecu reprogramed for a P3190 ect. 2nd Also I only use Chevron Gas 88 or higher. Thats just me you can take it for what worth. 3rd It is normal to see that go from 5mpg to 99 Remember it is not lateral it is in relation to what the injectors are doing. When you let off the gas the fuel is cut and the injectors are off so the display goes to max 99 mpg. when you floor it they are dumping in the gas display goes down 5mpg.
<div class='quotetop'>QUOTE(exces6\";p=\"68915)</div> I bet you were at Stage-3. http://www.priuschat.com/forums/kb.php?mod...de=article&k=14 Regards, Ken@Japan
<div class='quotetop'>QUOTE(ken1784\";p=\"69021)</div> I bet you were at Stage-3. http://www.priuschat.com/forums/kb.php?mod...de=article&k=14 Regards, Ken@Japan[/b][/quote] Ding, ding, ding....we have a winner!!! When the ICE is cold/in warm up it will not return to 99.9...I'm going to guess you're seeing this behavior mostly with a cold start and more than likely when you're running AC and/or defroster. Once warmed up completely you'll see 99.9 when off the gas. The drop in mpg during acceleration should not concern you at all, it is normal.
<div class='quotetop'>QUOTE(Kyle Pehrson\";p=\"68960)</div> Could you walk me through your reasoning here Kyle. I'm, frankly, suprised to hear you use something other than the recommended 87 octane and have to wonder if you're doing yourself and your Prius a disservice by doing so.
Tires might explain a sudden drop in mileage. It did in my case. Now I'm diligent. The "less than 99.9MPG coasting" might be a result of "behind the scenes" engine operation. I see this all the time. I don't know exces6's location, but when it's cold here, the engine will run to maintain the cabin heat or to warm itself after long periods of inoperability. Subsequently, even when there are no arrows on the display - or even when it shows regen - the MPG stays below 99.9. Remember, the MFD only shows the energy being used to power the wheels and the energy recharging the battery. I truly wish it would show when the engine is running to operate the A/C compressor when at a standstill, for example. [edit] The problem with opening multiple threads in multiple tabs in Firefox is that by the time I get to the latter tabs, a dozen people have already posted replies. Oh well. The more the merrier.
Tony, running the engine to operate the A/C compressor? The compressor is electric on the THSII. The engine would only operate to charge the HV battery. Now running the engine to get heat for the cabin, THAT I could understand.
Half right, half wrong. Six of one, half dozen of the other. Thanks for keeping me straight, Dan. If only to make sure that I'm not randomly confusing people.
Thanks everyone. Should I change the tire pressure from what it was when I got the car? If so, what should it be?
Evan We are at 6000 feet Sorry I forgot that most everyone else is not. The gas pumps here are mostly 88. some cust that live in Park City have to run 91 or they will ping if it is not pinging don't go up. I could get better gas mileage in summer if I used 91 than if I used 88. In the winter it will not make a difference at all. I have never had a bit of trouble.
Tire Pressure is 35 psi on front & 33 on the rear some people set them higher to improve gas mileage but you will sacrifice some handling.
http://www.priuschat.com/forums/mileage-ve...ure-vt1179.html http://www.priuschat.com/forums/dealer-had...005-vt5497.html http://www.priuschat.com/forums/the-cant-g...lub-vt2975.html http://www.priuschat.com/forums/mpg-droppe...kup-vt4648.html
just a quick question about Dan's response to Tony's response... It is the "only operate to charge the HV battery" statement I have a question with. It seems to me that as I drive around in the below freezing weather for the last several months, the ICE runs during the first 10 minutes (at least) to get itself warm and then runs to keep itself warm as it cools just by driving through cold air. Regardlesss of whether cabin heat is on or not, I do believe the ICE will be running (intermittently) to maintain this high engine temperature. This seems to be consistent with low emissions, doesn't it? The engine wants to be warm to operate most efficiently. I would posit that is what exces6 is seeing/experiencing - not low tire pressure. Once again, it's cold out there folks. You're operating an engine. Performance does have something to do with ambient temperature.
Yes, that would be to produce HEAT, not to run the AC compressor. If you are sitting there in park, the engine will not run to maintain its temperature (other than during initial turn on), but rather only to maintain HV charge. I had this experience when I first got the car in August, running the AC while playing with the NAV. Engine ran only to keep SOC at 2 bars. Now once you get going, MPG is low to warm the engine/catalytic, and to bring SOC to 6 bars. I guess Toyota doesn't figure running the engine for 30 seconds to maintain SOC is long enough to cause an emissions issue, especially since this will not be a frequent occurance. Even while driving, when I ran into stop and very slow traffic, the battery ran down. ICE started only for about 30 seconds, and usually only started if I moved. When I stopped, it stopped, but seemed reluctant.
