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Strange engine and battery usage

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by adam_d, Jun 5, 2015.

  1. adam_d

    adam_d Junior Member

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    Hi guys,

    My car has been doing odd things the last couple of days on my commute to work. I thought it was a one off at first, but they have both happened in the same circumstances over the last couple of days.

    First issue I have noticed is that on the latter part of my commute, for the last 20 minutes or so I'm in a stop-start traffic jam every day, speed is around 0-20mph. During this time over the last few days, the car will fire up the engine and then leave it on, even when the MFD is showing I'm only using the battery to drive. No charging status appears, I can only tell because I hear it and the instant MPG is not 99.9. It's been around 13 degrees in this situation the last few mornings, so I have no A/C on, and the car has usually been going for around 45 minutes/26-27 miles at this point so is quite warmed up.

    The second issue is to do with the battery charge when the car is off. The battery seems to be dropping charge when parked outside of work. The car is in the sun most of the day, temperatures get up to about 18-20. Again just over the last few days, it seems to be losing 2-3 bars over the course of about 7-8 hours. The first time this happened I returned to one purple bar, and it took about 3 miles with the engine on and reduced performance before the charge started to increase. Again, I left the A/C off to try and help it out.

    Besides these occurences, the car is fine. Once it's picked it's charge back up it goes fine and hovers between mid blue bars and the first green bar. I have no warning lights, and fuel consumption has only dropped a couple of MPG because of the morning part where it leaves the engine on in traffic.

    The car is a 2007, just coming up to 66k miles, 14k of which have been with me. I replaced the 12v battery 3 months ago with a genuine Toyota battery. I'm charging my laptop now and I'm going to put the Techstream on to see if anything looks strange there, is there anything specifically it sounds like I should look at? As I say, outside of these two situations the car is working perfectly as it always has, so I'm still unsure if this is just a temporary blip and will sort itself out.

    Thanks. :)
     
    #1 adam_d, Jun 5, 2015
  2. bisco

    bisco cookie crumbler

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    on the first issue, what level is the battery gauge?
     
    #2 bisco, Jun 5, 2015
  3. ExMachina08

    ExMachina08 Junior Member

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    Could also be the "idle dance" or your engine dropped out of the optimum heated range. Do you have a scan gauge or other OBDII reader? Check engine temps when this occurs.
     
    #3 ExMachina08, Jun 5, 2015
  4. adam_d

    adam_d Junior Member

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    It has been on the highest blue bar each time it has happened.

    I have an ELM327 and Torque, I only thought to use when I got home today. I will run it over the next few days and log temperatures. Just seems a little strange it stays on for so long, and any forward movement it seems to want to use the engine rather than the battery, you have to be very gentle to get it to just use battery when it's running like this.

    Thanks.
     
    #4 adam_d, Jun 5, 2015
  5. bisco

    bisco cookie crumbler

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    i hope your battery isn't going south.:unsure:
     
    #5 bisco, Jun 5, 2015
  6. ExMachina08

    ExMachina08 Junior Member

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    Sounds like you are dropping out of S4 mode and into S3 which would react similar to how you describe it. Having to feather the throttle to keep it electric. Log the temps and see what you think. I would suggest taking a look at ccdisce's ECT spoofer if you have long runs at low speed it will keep your engine in S4 by feeding the ECU a false temp. Great little addition to the Gen II and makes a huge difference, especially during cold starts and low speed cold days.
     
    #6 ExMachina08, Jun 5, 2015
  7. adam_d

    adam_d Junior Member

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    So do I! I have been keeping up the Hybrid Health Checks at Toyota though, so I should still have a bit of warranty left on it yet...

    That looks a good idea, didn't know it existed. I will record the temps and see how it goes. I might look into that but as I say, I should still be inside the warranty, so if anything is going bad I don't want to void it just yet.

    Thanks
     
    #7 adam_d, Jun 5, 2015
  8. dolj

    dolj Senior Member

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    I agree with ExMachina re dropping back into S3(b). You can read about the 5 stages of hybrid warm up by clicking on the second link in my sig below, if that interests you.

    Also, you say that you have the A/C off, but I am picking that, at 13℃, you have the heater going. If that is the case, it will keep the ICE running if the engine temp drops too low, which can happen in cooler temps and in stop/go traffic. That is easily verified by turning the climate control completely off using the steering wheel button. If the engine stops almost immediately after that then it is the request from you for heating that is keeping the ICE running.

    If you are driving your car by "encouraging" it to run on the electric motor for the last couple of miles before parking up, it can give this illusion. I say illusion because there is a delay with the battery SOC (state of charge) on the display. The illusion is caused by the fact that the HV battery has a lower charge than that displayed when you come to rest, as the display has not had time to refresh to the reflect its true SOC, but when you start up again at the end of the day, it does now show the correct SOC. If you do find yourself with purple bars on start up, you should remain stationary and allow the car to complete its stage 1 warm up, which only takes about 50 sec (although it seems longer), before moving off. If you drive off immediately this puts further drain the HV battery (by design) as it performs S1 warm up while you drive, to keep emissions low during initial warm up. You can force the ICE to start immediately after the READY light comes up by pressing the go-pedal momentarily, thereby saving waiting a further 7 secs for the car to do this of its own accord.

    The outside air temperature of 18-20℃ will not be a problem unless over the course of the day the interior temp is getting above ~35-40℃ for a prolonged period, such that the battery modules are getting warmed. The only thing you can do is try and mitigate that by parking in the shade or using one or more sun screens on the window(s). Although I don't believe it is an issue, if you can park out of direct sunlight, you should do so anyway.

    Hope that helps somewhat.
     
    #8 dolj, Jun 5, 2015
    Last edited: Jun 5, 2015
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  9. adam_d

    adam_d Junior Member

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    Well, I've been keeping tabs on the car since I've posted this and everything seems fine, it hasn't exhibited either of the above behaviours, so I'm going to put it down to something with my driving in these situations I think that I've now become more concious of.

    The last few miles I do tend to encourage it yes, but this is just due to slow traffic. The last 1-1.5 is quite quick again so it gets a little boost, so that was probably what I was seeing. Infact, the week after I posted this I got my best fill to fill MPG value of 68.7 Imp. MPG, so I'm pretty happy with that.

    Thanks for the helpful pointers with regards to the varying states and the ECT spoofer. Up to now I've just been driving the car normally, I haven't tried to learn any techniques deliberately to try and improve things, so I'm going to start looking into better learning how the car is working, and try to get the hang of things like pulse and glide.

    Thanks. :)
     
    #9 adam_d, Jun 23, 2015
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