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What is 'normal' for electric/ICE balance? Getting low MPG, trying to figure out why.

Discussion in 'Newbie Forum' started by Ashyukun, Dec 4, 2014.

  1. Ashyukun

    Ashyukun Junior Member

    Joined:
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    Location:
    Lexington, KY
    Vehicle:
    2005 Prius
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    So, I picked up a 2005 Prius a few months back to fix up (it had not been kept up well by its previous owners, and has over 260k miles on the odo) and both have as a temporary vehicle while I worked on my wife's car and then to sell after resolving its issues. It has largely been the car I've driven for the last few month as my other car is a relatively inefficient and finicky exotic that just isn't well suited to winter driving.

    It's pretty consistently gotten in the mid-30's for mileage in my mostly short-trip driving around town- the bulk of my driving of it is the 3.5 miles to and from work (most of the time I bike). It will get solidly higher when driving on the highway- I drove it about and hour and a half each way on the high way and it knocked the average MPG up into the low 40's. Everybody I know (which is very few, and none local unfortunately...) who owns a Prius is shocked at how low the mileage I'm getting is. It's still better in-town than anything else I've got or have driven (my bicycle aside), but seems to be way lower than what it should be getting.

    To me, it seems like it is far too eager to kick the ICE on and really resists running in golf cart/stealth mode, especially when starting off from a stop. Unless I'm starting with the nose pointing at least slightly downhill the the ICE will kick on almost immediately, usually not much above 10MPH. If I'm on an upward incline it pretty much does turn on as soon as I let off the brake and push on the gas. If I've managed to feather it into running electric-only at speed, it will stay there reasonably well if I'm on level ground or headed downhill, but when I encounter any kind of hill and it will take a bit more power it kicks the ICE on. This isn't always easy to show- but thankfully I have a ELM-327 and an app that lets me log data from it, so I have a plot of speed & engine RPM. Unfortunately I can't upload it from my work computer and will have to do it from home later. :/

    I've not seen any OBD codes that would indicate problems with the traction battery, and have not had the Triangle of Doom ever come on- but I also at the moment do not have a Mini-VCI to be able to really look into things, largely because I don't have a laptop that can run the software so picking up the mini-VCI alone wouldn't do me much good. Unfortunately the logging app (Dash Command) doesn't seem to have the custom PIDs for the Prius, but another one (EngineLink) that doesn't log but will show more of them lets me pull up the PIDs for the voltage out of HV Blocks 1-14, and I haven't ever seen more than a .05V or so variance between blocks.

    The current MPG doesn't bother ME that much as it is still much higher than any other options, but expect when it comes time to part with it that if it's only getting in the 30's it's going to be a concern. So, I want to figure out what the issue is- and ideally, fix it for as little cost as possible. I can do most anything I need to with regards to cars & electronics myself, so that helps a fair bit.

    So, I'm curious as to what I'm seeing indicates from everyone else's experience and what the steps to take to figure things out should be. Thanks!
     
  2. bisco

    bisco cookie crumbler

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    Plug-in Base
    how is the 12v health? there are so many possibilities besides the hybrid battery. (not to say it isn't the hybrid battery, but until you can test it, you might as well look elsewhere) has it had all the necessary services for the mileage? what tyres are you running?
     
  3. fotomoto

    fotomoto Senior Member

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    Mid 30's for a 3.5 mile drive is GREAT! The ICE never gets enough time to warm up especially now with the cooler fall temps.

    Do a little experiment: reset the meter and take a good long 20ish mile drive around town and see what mpg figure you get. You might also want to research "grill blocking".
     
  4. Ashyukun

    Ashyukun Junior Member

    Joined:
    Oct 18, 2014
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    Location:
    Lexington, KY
    Vehicle:
    2005 Prius
    Model:
    N/A
    Somewhat questionable- I'm actually waiting for a chance (hopefully will get it tonight) to try and swap the current battery out for the old battery that came with the car. It's a long story- it's already been discussed a good bit (very heatedly, at times...) in a previous thread: Time to replace the aux battery? | PriusChat


    I'm planning on resetting it and seeing what the true highway MPG is when I head out on a highway drive tomorrow, I can see about the in-town test later. The grill blocking is an interesting idea, I'll have to look more into that.
     
  5. bisco

    bisco cookie crumbler

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    rather than a highway drive, you should try 20 miles on 30-40 mph roads.
     
  6. Ashyukun

    Ashyukun Junior Member

    Joined:
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    Location:
    Lexington, KY
    Vehicle:
    2005 Prius
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    N/A
    I needed to make the highway drive regardless, so it was happening anyway. ;) Ended up averaging about 45mpg for the 80 mile or so each way drive, generally doing the speed limit (70). Haven't had a chance to take a long drive on surface streets- driving 20 miles on 30-40 MPH roads isn't the easiest here because it's herd to go that far on what one we have...

    Tried uploading the graph, but for some reason it keeps failing...
    40 mp
     
  7. fotomoto

    fotomoto Senior Member

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    I see nothing wrong with your car. Once the engine (ICE) is warm, it delivers good mpg. Short trips KILL mpg's even hybrids that's why plug-ins really work for most folks driving. You'll get better mpg on you short drives in the warmer months.
     
  8. MyBoySaturday

    MyBoySaturday New Member

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    Vehicle:
    2005 Prius
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    Hi I'm curious what you found (a year later). I used this thread and others when making my decision to buy a used 2005 Prius with 66k.
    I noticed too that I get terrible mileage on short trips (I live in a very hilly area too).

    However, I found highway mileage to be superb and of course, MPG in town improve with longer trips. (the terrain still kills my economy)

    I used Torque on my previous car, but I hadn't used any custom PIDs yet. What was your experience? (Also is there anything to Torque's warning screen on PIDs?)