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HELP! Concerns about mpg,hybrid battery and or CVT

Discussion in 'Gen 2 Prius Main Forum' started by Frost32, Jul 9, 2012.

  1. Frost32

    Frost32 Junior Member

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    I just bought a 2009 Prius from a dealer and the last 2 weeks I have noticed the hydrid batteries reads in the blue 3-4 bars down most of the time even after driving for awhile it goes up to the 2nd bar down (green) then when I drive for a couple of minutes it goes right back down. I also notice that I am NEVER using just hybrid motor power The gas engine is constantly showing and the only time the power returns to the battery is when I take my foot off the gas completely or hitting the brakes. When I am at a stop if I don't hold the brake down hard the hybrid motor shows running until I press further down on the brake pedal. I can't seem to get the car to a glide so I can less power to maintain speed and it seems like the CVT is in B mode. Also at higher speeds trying to pass it feels like the cvt is slipping?.? I try to use a feather touch on the gas but can't see to find a point where the car will not use gas power constantly. I drove my bosses 07 and his gets like 4-5 mpgs better than my 09. His car has 130k and mine only has 95. His car can run and glide on hybrid motor and the gas engine is not constantly powering the vehicle like mine does. I get only 38-39 mpgs he gets like 44. We both drive about the same time on the road. My commute to the job is about 1/2hour and then I am on the road off and on to appointments. Did I get a lemon or maybe just a bad sensor? Any help or advise is greatly appreciated
     
    #1 Frost32, Jul 9, 2012
  2. Frost32

    Frost32 Junior Member

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    Btw I have pics of screen and a video I will upload later
     
    #2 Frost32, Jul 9, 2012
  3. fuzzy1

    fuzzy1 Senior Member

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    #3 fuzzy1, Jul 9, 2012
  4. edthefox5

    edthefox5 Senior Member

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    Yeah thats not right. You seem to know how it should run too so thats helpful. Since your not throwing CEL's I would suspect the 12 volt boot battery in the trunk and tune of motor. I can almost garantee you need a new 12 volt battery.
    There's a easy method to check it on the MFD but I am at work so do not have the link. Someone will be along soon and post it. Anything below 12 volts on step 3 Under Load and the battery is toast. It will kill the mileage. Around $180 for a Optima Redtop. Much better battery than stock.

    Next pull the air cleaner out an look down the throttle body throat and see how dirty it is. I bet its very sooty. That really affects mileage and driveability. Search back my old posts as I have an easy & detailed method to clean it. Do those and report back.
     
    #4 edthefox5, Jul 9, 2012
  5. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    This part seems normal.

    You need a reserve in the HV battery so you can absorb the energy when you hit the brakes. If you brake slowly from about 80 MPH or down a long down hill you may fill the HV Battery, in which case the car switches from regenerative braking to friction braking as then there is no 'room' to put more electricity.

    Here is a link like EdtheFox5 promised:
    Weird stuff happening? MPGs dropping? Test The Battery | PriusChat
     
    #5 JimboPalmer, Jul 9, 2012
  6. scotthershall

    scotthershall New Member

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    Definitely sounds like a 12v battery issue. That's a simple fix if you have very modest mechanical ability.

    It's really hard to "top off" the battery unless you're going down hill. If you live in a flat area it might be difficult to achieve. What you want to keep an eye out for is fast drops in the number of bars. That could indicate a bad traction battery. Using the AC will use up the juice quick, BTW.

    Keep playing with the accelerator... the point at which the car "glides" is really difficult to find, for me at least. It shouldn't, however, be difficult to accelerate in all-electric mode. Find a flat spot (parking lot?) and give it no more than 10% throttle. Unless the traction battery is in the purple zone, you should be able to achieve EV driving until it hits purple.

    Scott
     
    #6 scotthershall, Jul 9, 2012
  7. Frost32

    Frost32 Junior Member

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    Thanks guys. I had aleady been on here and suspected the 12v battery at first. I did change the battery to the optima yellow top already and changed the air filter (it was filthy)and put about 48psi in the front tires and 44psi in the rear. I am still getting only about 39mpg. I have not checked Throttle body and was thinking of new plugs and fuel filter I would like to see the car get at least 45 mpg. I can't even touch the gas pedal without the gas engine showing it is on. maybe slipping is the wrong word for the feeling and noise I hear from cvt. it seems like a straining when I accelerate harder to get on highways and the mpg monitor goes way down to like 8-9mpg even slight acceleration from 45 mph to get to 55 will drop mpgs in half and I am not accelerating hard at all. As far as the regen battery I was not aware that battery would be ok in the upper range of the blue bars I never even knew there was a purple. I would have freaked if it went that low. I was concerned because it does seem like the bars drop quickly. When I start up I am in the green , not topped off EVER but second bar down and it goes pretty quickly to first or second blue bar in minutes then as I drive it will come back a bar and sometimes back to green bar but does not hold there even while driving. You guys are the best! Gotta see how to clean the throttle body.
     
    #7 Frost32, Jul 10, 2012
  8. uart

    uart Senior Member

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    Ok, so by the way you're counting them, the second bar down is the 1st green (7th bar) and the 3rd bar down is the top blue (6th bar). In this case what you are seeing re the state of charge is 100% normal.
     
    #8 uart, Jul 10, 2012
  9. uart

    uart Senior Member

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    Frost32, what's the temperature like there at the moment. You could have either the inverter or HV battery running too warm, in which case it may rely too much on the engine and not allow you to use full electric mode.

    After driving around for a while stop the car (stay in ready mode) and turn off all fans and stereo, do you hear the battery fan running in the back (vent near the right side back seat).

    You should also check that the inverter coolant is circulating correctly. If you search the forums you'll find several posts outlining how to easily do this.
     
    #9 uart, Jul 10, 2012
  10. usnavystgc

    usnavystgc Die Hard DIYer and Ebike enthusiast.

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    It seems to me you are not putting the car in S4. This is a simple fix. You just need to read up on the stages of Prius operation. Here they are.

    To get the car in S4, you need to come to a complete stop (after the engine is warmed up) for 7-10 seconds. When you come to a stop in S3b, the engine will be running. You must stay stopped until the engine shuts off. This will def increase your gas mileage and allow you to get into a glide/full electric mode. All of what you describe is typical of S3a or S3b operation.

    Try it and report back.
     

    Attached Files:

    #10 usnavystgc, Jul 10, 2012
  11. dorunron

    dorunron Senior Member

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    Hi Frost,

    Take a look at post #3 in this string. There is a link there to a questionaire. If you can fill out the form and then post the results, it should help to determine why you are getting 39 MPG.

    FYI, I have seen worse mileage than that in various conditions with the 09 Prius that I drive. I normally get around 45, but I can actually get a lot worse if I really try to. There are many factors that effect mileage in the Prius.

    As far as your comments on the traction battery, I think what you are seeing is normal. It is normal for the battery SOC to be blue most of the time. It can be green at times due to a lot of regeneration, and can get purple at times due to heavy usage. Toyota designed the Prius to maintain the SOC between 40-80% and the readings that I mention fall into those ranges.

    I will say this without even looking at your answers to the questionaire right now. If your trips are short, and ambient temps are very cold or very hot, 39 MPG would not be considered extremely bad. Poor yes, but bad No.

    It would really help if you would take the time to fill out the form and post the results here in this string.

    I have reposted the link for you directly below this paragraph.

    Fuel economy complaints/queries? Please copy, paste & answer these questions, esp. if you're new | PriusChat

    Ron (dorunron)
     
    #11 dorunron, Jul 13, 2012
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