1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Prius cold engine knock poll

Discussion in 'Prius c Care, Maintenance and Troubleshooting' started by bwilson4web, Nov 26, 2012.

  1. bwilson4web

    bwilson4web BMW i3 and Model 3

    Joined:
    Nov 25, 2005
    27,335
    15,487
    0
    Location:
    Huntsville AL
    Vehicle:
    2018 Tesla Model 3
    Model:
    Prime Plus


    I know this is the 1.5L forum but we're trying to characterize what it takes to reproduce the 1.8L Prius, cold-start, engine knock. What I don't know is whether the 1.5L engine has a similar problem . . . hopefully not!

    The engine knock is intermittent and rare but if we can come up with a protocol that reliably reproduces it, we have a chance of getting effective, corrective action. If you've had the knock, recently, please take the poll and add any additional details that might lead to reproducing this problem at will:

    Reproducable knock? | PriusChat

    Thanks,
    Bob Wilson
     
  2. tk1971

    tk1971 Active Member

    Joined:
    Jul 24, 2012
    253
    133
    0
    Location:
    SG Valley, CA
    Vehicle:
    2012 Prius c
    Model:
    One
    Got it this past weekend. Started the car up (it was cold) and started backing out of the driveway. Engine turned on and shook about 2 seconds before smoothing out.
     
  3. crebble

    crebble Member

    Joined:
    Mar 16, 2012
    176
    46
    0
    Location:
    Shohola PA
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
    Only had this happen one time. It sounded horrible. Like most everyone in the thread you linked, I had moved the car a very short distance (< 30')the day before without a proper warmup.
     
    orenji and vernon birdman like this.
  4. bwilson4web

    bwilson4web BMW i3 and Model 3

    Joined:
    Nov 25, 2005
    27,335
    15,487
    0
    Location:
    Huntsville AL
    Vehicle:
    2018 Tesla Model 3
    Model:
    Prime Plus
    This is beginning to sound like what happens when you try to start a cold engine with one of those 'engine start' sprays. I'm beginning to think:
    1. cold start engine - it is running in 'open loop' mode and may rev a little higher, pre-closed loop catalytic converter light-off.
    2. stop engine - as it coasts down, the spark is turned off but the injectors continue to run. This pumps raw gas in the manifold.
    3. cool down - all heat from the engine goes away so the residual gas vapors condense and pool in the bottom of the manifold. There might even be some in the exhaust manifold.
    4. 2nd cold start - not only is there the injected, 'open loop' gas but now the pool in the manifold leads to an excessively rich mixture. This in turn leads to the "knock" although I am not sure if we're hearing detonation knock or something else.
    Now some engines fire the spark plugs every rotation . . . I do not know if that is the case with our 1.8L engine. If so, having the cylinders, intake, and exhaust full of combustible gas vapor could easily lead to 'badly out of time' combustion and ignition.

    One of the reasons for this thread is I have an AutoEnginuity OBD system. I can hook it up and record the events of an engine knock IF I can reliably reproduce the problem. Everyone's contribution is moving us towards that goal and it is time to see if we can get this intermittent problem to become reproducible at will.

    THANKS EVERYONE!
    Bob Wilson
     
  5. markp13

    markp13 Junior Member

    Joined:
    Apr 10, 2015
    8
    1
    0
    Location:
    Vancouver, BC
    Vehicle:
    2012 Prius c
    Model:
    N/A
    This just happened to me. Car was driven normally then parked for four days. It was a pleasant spring morning - not too cold. Started up and heard loud engine knocking for around 4 seconds before it went away. Very worrying. It has not happened since resuming regular driving. I asked my Toyota service department to log the incident. I am hoping there might be a fix or recall in future under powertrain warranty.
     
  6. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    108,451
    49,290
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    not to worry, it happens to a lot of people, doesn't hurt anything, and is unfixable. try not to shut it down while the ice is running.
     
    orenji likes this.
  7. AliIzad

    AliIzad Member

    Joined:
    Aug 21, 2012
    170
    72
    0
    Location:
    Southern California
    Vehicle:
    2012 Prius c
    Model:
    Three
    It has happened to me three times; all during cold mornings following moving the car a short distance the day before. As nasty as the knock sounds, I'm not too worried about as it seems to be very common.
     
  8. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    108,451
    49,290
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    stop moving your car!:p
     
  9. markp13

    markp13 Junior Member

    Joined:
    Apr 10, 2015
    8
    1
    0
    Location:
    Vancouver, BC
    Vehicle:
    2012 Prius c
    Model:
    N/A
    Engine knocking and shaking just happened to me again after starting up having driven half a block only to move my car beforehand. Temporarily resolved when applying gas but returned again immediately. Please report these incidents to Toyota. This is not normal.
     
  10. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    108,451
    49,290
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    not normal, but so common, most have learned to live with it, or avoid it.
     
  11. markp13

    markp13 Junior Member

    Joined:
    Apr 10, 2015
    8
    1
    0
    Location:
    Vancouver, BC
    Vehicle:
    2012 Prius c
    Model:
    N/A
    If it's not normal (which it isn't) - it should be reported. Whether it's misfiring or moisture, Toyota needs to address it. Even if this is only happening every few months, it cannot be good for the engine long term. It has happened to me even when waiting for the ICE to stop running. It seems to be that very short trips and the angle of the car (whether parked on a slope) might be factors that contribute to the knocking.
     
  12. orenji

    orenji Senior Member

    Joined:
    Aug 17, 2013
    5,884
    3,486
    0
    Vehicle:
    2010 Prius
    Model:
    Three
    You need to let it run and only turn it off once the ICE shuts down. The ICE has to warm up, it takes about two minutes. Do this and it will not happen again. It's a non-issue, caused by driver error. Remember this is not a normal car and can't be driven like a normal car.
     
  13. vinnie97

    vinnie97 Whatever Works

    Joined:
    Mar 20, 2010
    1,430
    277
    0
    Location:
    Somewhere out there
    Vehicle:
    2018 Tesla Model 3
    Model:
    N/A
    Driver error? I disagree. Unless the manual advises against interrupting the ICE on warmup? :)

    Anyway, I noticed this on the 2010 Gen 3 liftback...as a result of the ensuing anxiety it caused and with the dealership unwilling to implement the supposed fix, I "upgraded" to the 2012 c. I *may* have noticed a slightly rougher start on occasion when recreating the required conditions in this vehicle, but it was nothing as severe as the liftback. As a result, I've been able to put it out of mind, but it sounds like some folks above are having the more violent knocking that I witnessed on the Liftback. I can't blame these folks for their dissatisfaction at all. The surefire way to prevent it is to not interrupt an ICE warmup, but that's a bit wasteful if you're only moving the vehicle a matter of feet. The other expensive solution is to upgrade to another vehicle altogether. ;)
     
    bisco likes this.
  14. orenji

    orenji Senior Member

    Joined:
    Aug 17, 2013
    5,884
    3,486
    0
    Vehicle:
    2010 Prius
    Model:
    Three
    The warm up is less then a minute during summer, maybe 3 or 4 minutes during winter, hardly wasteful.....or just don't move it around. :)
     
  15. CR94

    CR94 Senior Member

    Joined:
    Dec 2, 2014
    2,642
    1,136
    0
    Location:
    Northwestern S.C.
    Vehicle:
    2011 Prius
    Model:
    Two
    They could minimize the problem by allowing EV operation for those very short-distance moves, assuming adequate charge, etc.
     
    bisco likes this.
  16. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    108,451
    49,290
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    yes they could. do you think we'll get it on the gen IV?
     
  17. vinnie97

    vinnie97 Whatever Works

    Joined:
    Mar 20, 2010
    1,430
    277
    0
    Location:
    Somewhere out there
    Vehicle:
    2018 Tesla Model 3
    Model:
    N/A
    I'm actually able to use EV mode to move it without issue in the warmer months. Running the ICE for a few minutes in such a scenario may only be minimally wasteful, but it also contributes to further wear and tear. It's also why my next vehicle is likely to be a BEV or PHEV.
    You can switch to EV mode now actually if certain variables are met (high enough ambient temperature, adequate battery charge as you postulated, etc.). During the winter, forget about it (unless your garage is well heated).
     
  18. allquixotic

    allquixotic New Member

    Joined:
    Mar 22, 2015
    1
    0
    0
    Location:
    Maryland
    Vehicle:
    2015 Prius c
    Model:
    Two
    I made the mistake of moving my 2015 Prius C Two to a different parking spot on our two-lane driveway, and cut off the engine while it was warming up. Big mistake!!!

    Here is the sequence of events:

    Friday: back and forth to work as normal (90% highway for ~65 miles), plus a small amount of low-speed cruising around town for errands, but nothing out of the ordinary. Temps in the 80s F.

    Saturday: started up to back out of driveway and move to another parking space. I believe it is in what the Gen3 startup thread calls "S1a" (or possibly S1b, though it wasn't on that long) when I turned the hybrid system off. Temp was maybe 92 F in the sun (which the car was for most of the day). Hot day.

    There it sat, until Monday morning. when I was going to work mid-morning. The first several hundred turns of the crankshaft yielded what sounded like terrible knocking and grinding noises. Lots and lots and lots of misfires, maybe 50-80% of cylinder strokes were audibly misfiring. I can't tell if they were early ignition, late, or what... but the knock sensor seems to have worked, as you could hear that, as it started pulling the timings, the knocks became less and less frequent. By the time S1a was complete and the engine started to rev up a bit more for S1b, the knocks were basically gone. At that point, I started driving, and by the time I hit S3, there was no knocking. Temps were in the upper 80s.

    Then, on Monday night, Tuesday morning and Tuesday night, I got way fewer but still audible knocks during the first few revs of S1a. Maybe 1-5% of the revs were knocks, and they were a few seconds apart each.

    Oddly enough, the knocks have completely disappeared or are so minor as to be unnoticeable, for four cold starts of my car (Wednesday morning and night, and today morning and night).

    Seems like it's similar to what happens when water gets in your windpipe. You cough real hard for a few seconds, then for several minutes after, you feel like you could cough more, until you finally get rid of it, but it's pretty persistent.

    Wondering if I should take it into the dealer...
     
  19. orenji

    orenji Senior Member

    Joined:
    Aug 17, 2013
    5,884
    3,486
    0
    Vehicle:
    2010 Prius
    Model:
    Three
    No dealer needed, just allow the car to warm up and shut down the ICE before turning off the car. You should not experience this again. I also use 91 Premium fuel, not sure if this does anything to help or not. I have 42,000 miles and have not experienced it in the last 40,000 miles.