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ICE no longer shuts off!

Discussion in 'Gen 2 Prius Technical Discussion' started by medicis, May 16, 2007.

  1. medicis

    medicis Junior Member

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    My new Prius has been behaving strangely in the past 2-3 days. Until then, everything was perfectly in line with the 5 stages as explained in the sticky. I was P&G'ing happily and my regular commute, after writing off the first 5 minutes, was averaging 3.5 to 4 l/100. Nothing has changed in traffic conditions, weather, driving style, etc.

    Here is what happens now:

    1. During warm-up stage, ICE no longer switches off when car is fully stopped. Fuel flow is stuck at 99.9l/100 until I drive off. (I sure have no more complaint about the shudder I had enquired about in an earlier thread!!!)

    2. After warm-up stage (even after 15-20 min driving at regular speeds): whether I am in glide mode (no arrows at all), in pure regen or in EV mode, the instantaneous fuel flow remains at what seems to be an idling rate (1.5 to 2.5 l/100)

    3. All that excess ICE energy, of course, causes SOC to get pretty high in the green band, so that EV mode is more frequent and lasts longer

    4. Very occasionally, I have seen the ICE shut off as expected but the funny condition returns later

    5. My regular commute averages now well above 5l/100. Today, I got a 3 consecutive 5 minute segments maxed out (i.e. above 10 l/100). My usual pattern was: 1st segment maxed out or between 7.5 and 10, then down to below 4.

    I do think something is wrong. Any idea? Wild guess: if the engine temp sensor were faulty, could Prius believe she is still in warming up stage?

    I am not making this up.. will try to post some pictures. I'm also going to get a ScanGauge.

    Thanks, all.
     
    #1 medicis, May 16, 2007
  2. qbee42

    qbee42 My other car is a boat

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    Has it been colder outside? What you describe sounds like cold weather operation, where the ICE has to make heat to stay warm and keep the catalytic converter hot.

    Tom
     
    #2 qbee42, May 16, 2007
  3. Tideland Prius

    Tideland Prius Moderator of the North
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    Hmm... doesn't sound right (btw 3.5-4L/100km is awesome!)

    I'll just throw out some possibilities for you to consider.

    1. Make sure you weren't in B (although if it's been happening, I'm sure you couldn't have selected B every single time but I'm just saying it to double check)

    2. Did you park your car outside instead of the garage? The engine cools quite quickly

    3. Did it suddenly get colder? (you don't say which prov. you're in)

    4. Perhaps it's bad gas? Run the tank down and refuel it again

    5. Did you check your climate control? It might be at 22.5°C or higher

    6. Front defroster on?

    7. Fan on hi?

    That's all I can think of.
     
    #3 Tideland Prius, May 17, 2007
  4. bulek

    bulek Junior Member

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    CO2, first of all thanks for posting this... right now at least I don't feel alone with my problem (which is exactly the same as yours). I tried to describe it on the forum some time ago but just got usual advices like it is normal because it's "too cold", "too hot", "AC on", "strong wind", etc. I can understand these replies because it's hard to explain to all "normal" Prius owners that it's not just imagination. Well... the best advice was to have fun with driving and stop watching MFD and this is what I actually did (almost) :D.

    Just to give some background my car was "normal" for the first two weeks after purchase and then it started working as you described. I connected this point of time to my first visit in autowash station but I can't be sure that that was the reason. So on short city trips (10km) from cold start I am not able go below 6-7l/100km. During such trip I am trying sometimes to release slowly gas pedal and fuel consumption goes down to 6l/100km and then directly to yellow or green arrows mode (while ICE is still running). No way to enter glide mode. When sometimes the car works properly I can go down to 2l/100km before the ICE goes off and then battery, glide or regen mode appears on the screen.

    I noticed also that I can drive very very slowly for 5 min (in whatever mode) and ICE will not go off but as soon as I stop it also stops after a few seconds. Sometimes even after driving with fully warmed car for 30 min ICE enters warming up mode again.

    Out of the city trips seem to be ok in general. Maybe with this exception that I saw here and there reports about getting 50-55 MPG without even trying to P&G. If I drive in this style I get no better than 5.3l/100km (44 MPG).

    It's interesting what you said about temperature sensor. Maybe my visit in wash machine "broke" it somehow?

    - Piotr
     
    #4 bulek, May 17, 2007
  5. brick

    brick Active Member

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    The temp sensor was my first thought because that plays a big role in the Prius "stages" of warmup. My other thought is that if the ECU has changed its programming for some reason you might want to try resetting it by disconnecting the battery negative cable for a period of time. That should reset it back to its original state.

    Once in a while my Prius acts flakey for a mile or two but it always resumes normal engine shutdown once it's had time to warm back up/heat the cat/feed the hamsters/whatever.
     
    #5 brick, May 17, 2007
  6. dmckinstry

    dmckinstry New Member

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    <div class='quotetop'>QUOTE(Tideland Prius @ May 16 2007, 11:57 PM) [snapback]443984[/snapback]</div>
    Actually your profile doesn't indicate your province either. Is that a secret, or have you already mentioned it elsewhere?

    If you're in BC, as some of the PC members, I'd like to know.

    Dave M.
     
    #6 dmckinstry, May 18, 2007
  7. medicis

    medicis Junior Member

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    <div class='quotetop'>QUOTE(Tideland Prius @ May 17 2007, 02:57 AM) [snapback]443984[/snapback]</div>
    Surprise!

    After 3 days of consistent misbehaviour, as described, everything is now back to 100% normal: ICE shuts off when car is stopped and after warmup during glide, regen and EV. My tank average, which had been steadily deteriorating, is now creeping back down (in l/100km). Outside temp is marginally higher (15C) but I am pretty sure it was just as high when the problem started. So, maybe she was just in one of her moods!

    For the record, I'll answer Tideland's questions for future reference. It may help someone else:

    1. I wouldn't have made it in time to the office... anyway, I have never used it.

    2. It's always outside.

    3. First bad day was about 15C then it did cool down (5-10C). I doubt this was it.

    4. Regular unleaded major brand. Problem has disappeared before refueling.

    5. Air cond was off. Temp selection approx 20.

    6. No defroster

    7. Fan on low.
     
    #7 medicis, May 20, 2007
  8. F8L

    F8L Protecting Habitat & AG Lands

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    Could your AUX battery have been low or having charging issues? That would cause the ICE to come on more often or even stay on if the battery wasn't holding a charge right?
     
    #8 F8L, May 25, 2007
  9. Khardan

    Khardan New Member

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    Ten years later I just managed to acquire a Prius (2006), and experience exactly the same issue. Even the local servicemen have no idea. I am wondering if you ever figured out what caused the problem and how to solve it? That would be a huge help.
     
    #9 Khardan, Sep 15, 2017
  10. Prodigyplace

    Prodigyplace Senior Member

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    You should start a new thread. You cannot expect people from 10 years ago to still be here and remember that far back.
     
    #10 Prodigyplace, Sep 15, 2017
  11. bisco

    bisco cookie crumbler

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    have you checked the 12v health?
     
    #11 bisco, Sep 15, 2017
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