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Engine misfire when starting with low hybrid battery

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by BradC, Jun 2, 2019.

  1. BradC

    BradC Member

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    I have a 2014 Prius with about 126K miles on it. Just had the oil and engine coolant replaced on Friday. Did the spark plugs when specified, at 120K miles.

    On Saturday, I started it up and noticed the hybrid battery was very low. The gas engine kicked in and did this weird misfire a few times. It didn't happen again, and hasn't happened since, but it was odd.

    No check engine light or anything else came on. Any thoughts on what it could be? Thanks.
     
  2. fotomoto

    fotomoto Senior Member

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    Very vague description; more detailed info will help.
     
  3. Raytheeagle

    Raytheeagle Senior Member

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    Did you park it with the battery low?

    Usually when the battery is low, the engine has to rev up to charge it.

    I wouldn’t pay it too much mind, but keep an eye on the levels just in case.
     
  4. BradC

    BradC Member

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    The charge level on the hybrid battery was very low, so it needed to recharge. That's why the gas engine kicked in.

    I didn't notice the battery level when I parked. I was going to the grocery store, and when I drive around town, I typically use the hybrid battery more because I try to drive with just the electric motor as much as I can.

    So when I started the car, the gas engine kicked in because the hybrid battery level was so low. Then I heard the gas engine do some kind of misfire 3 times. After that, it seemed to run fine, and it was okay after that. No issues since.

    It made me a bit nervous, though, because I work out of town, so I do a lot of driving. I don't want to get stuck in the middle of nowhere, so I'm very careful about keeping up on my maintenance.
     
  5. CR94

    CR94 Senior Member

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    !! That practice is tough on the battery, and probably your mpg too. I don't see why it would cause misfiring, though.
     
  6. CR94

    CR94 Senior Member

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  7. BradC

    BradC Member

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    Why is that tough on my MPG? I’ve had trips around town where my MPG has been 60 or 70, if I stay below 40 MPH as much as I can and drive on the electric motor as much as possible. I thought that was a useful trick.
     
  8. Mendel Leisk

    Mendel Leisk Senior Member

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    Ever checked the Exhaust Gas Recirculation system, intake manifold, looked into Oil Catch Can?

    Clogging of the EGR system and intake manifold, coupled with a steady diet of oil/water/gas dreck to the intake manifold via the Positive Crankcase Ventilation system is causing a couple of common problems:

    1. As the EGR system inexorably clogs the engine runs hotter.
    2. The PCV system dumps sludge into the intake and likely more just flows through (as an aerosol) into the combustion chamber, carbon coating the piston rings and the EGR passages.

    I would lift off the throttle body (leave coolant lines attached, no need to disconnect), clean it with carb cleaner on a cloth, check the condition of the intake manifold directly below. It's pretty much a slam dunk that it will be a swimming pool. That's the stuff an Oil Catch Can will catch.

    Also, remove the EGR pipe (the connecting pipe between EGR valve and intake manifold) and check it's degree of clogging. This is just the tip-of-the-iceberg of the EGR system, but easy to get to, gives you some idea what to expect for the remainder. The EGR cooler, connecting to the exhaust, is likely to be weekest link, most clogged. There are EGR passages in the intake manifold as well, and it all clogs over time.

    Some info:

    Nutz About Bolts Prius Maintenance Videos | PriusChat

    Good thread:

    EGR & Intake Manifold Clean Results | PriusChat

    Another:

    Oil Catch Can, Eliminate that knock! | PriusChat
     
    #8 Mendel Leisk, Jun 3, 2019
    Last edited: Jun 3, 2019
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  9. mjoo

    mjoo Senior Member

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    That's a classic symptom of PCV liquid in the intake manifold. The IM design pools the liquid at the bottom of the manifold near the throttle body and then gets sucked into the cylinders on startup. The dealer "fixes" it by replacing the IM with a newer part number which mitigates the problem but doesn't eliminate it (plus the clean new IM helps).

    Until @danlatu came along we had no recourse except to avoid a quick startup/shutdown:
    Oil Catch Can, Eliminate that knock! | PriusChat
    (mods this thread should be stickied)
     
    #9 mjoo, Jun 3, 2019
    Last edited: Jun 3, 2019
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  10. BradC

    BradC Member

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    An update: I took it to my mechanic today. He said no codes appeared when he hooked it up.

    He suspects it's probably an engine coil going bad. Our Honda Odyssey has exhibited similar behavior in the past and has needed a couple engine coils replaced, so that makes sense.

    However, he can't determine which coil it might be, so he said to wait until the check engine light goes on.

    He said it would cost $500-$600 to replace all 4 coils, so I might just do that as soon as I can afford to do so. Since I put ~400-500 miles on the car each week, I'd rather be safe than sorry.
     
  11. Mendel Leisk

    Mendel Leisk Senior Member

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    The coils (item 1) are $73 apiece plus shipping here:

    Ignition System for 2014 Toyota Prius | McGeorge Toyota Parts

    Put 4 coils in a basket and fill in your info, see what the shipping would be.

    Watch @NutzAboutBolts video #13 here:

    Nutz About Bolts Prius Maintenance Videos | PriusChat

    It takes you step-by-step through the labourious but straight forward wrenching involved. It's not that hard, and all-in I think you could easily DIY it for around $350.

    To be fair to your mechanic, maybe he's stuck with the full retail price? It's noted in the above link, $109 apiece. That would make his quote reasonable, but still: it's an easy DIY, saves $150~250.

    If the plugs are going to be replaced, they require a 14 mm (or 9/16") spark plug socket, and the torque is 15 foot pounds with clean/dry threads. If you use anti-seize, I'd say use it very lightly, maybe put it on and wipe off, just leave some in the threads. And reduce torque to maybe 12 foot pounds. Use a 3/8" drive torque wrench, not 1/2", it's quite a low torque value.
     
    #11 Mendel Leisk, Jun 21, 2019
    Last edited: Jun 21, 2019
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  12. BradC

    BradC Member

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    He said they were around $100 each, so I guess he has to pay full retail. I just replaced the spark plugs at 120K miles (I’m close to 130K miles now), so I can’t imagine those need to be switched out.

    TBH, I’d rather pay him to do it and ensure it’s done properly. I can change my oil and do a few other things, but I’d rather leave something complicated like this to a pro.

    Thanks for the info.

     
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  13. Mendel Leisk

    Mendel Leisk Senior Member

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    Yeah or buy them yourself and supply to him. (y)
     
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  14. cnc97

    cnc97 Senior Member

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    Aftermarket coils are 229 for all 4, or 81.49 each. Since I work at a parts store, I opened a box of 4 just as a check. Three of the 4 coils in the box had a Toyota part number on them. I then opened the two single coils that my store also had in stock and found another one with a Toyota part number. That tells me the main supplier for my store chain is the same as OE. Someone will get the benefit of a 4 pack of OE coils for the price of 3 from the dealer. If you know your parts guys, they should be willing to let you do this. I make more money taking care of customers like that.
     
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  15. Raytheeagle

    Raytheeagle Senior Member

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    You can always stop by my place on your travels and we could gave this done in less than an hour;).

    Not a hard job at all and the windshield wiper cowling isn’t that bad of a job to remove(y).
     
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  16. BradC

    BradC Member

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    I’ll PM you. Thanks!

     
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