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Starts then stalls

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by turboj91, Jul 23, 2008.

  1. turboj91

    turboj91 Junior Member

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    Vehicle:
    2012 Prius
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    II
    2002 model. Runs and drives great with 149K. Usually 48 mpg. Starts fine and runs for approx 10-15 seconds and then stalls. It will immediately restart and then stall. The cel is on at this point.

    If I start the ice then shift to neutral, I notice a change in rpm and the car will not stall. After a second or two in neutral, I can shift back to park or into reverse or drive and it will not stall. Who would have ever thought that shifting into neutral avoids a stalling problem.

    Also, if immediately after starting I shift into drive and accelerate hard enough to get the ice rpm above the idle speeds it will not stall when I let off the gas

    From what I have been able to determine, it's an ecm issue. Any thoughts? Thanks in advance for your opinions.
     
  2. doubleg2005

    doubleg2005 Member

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    it's supposed to do that?
     
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Vehicle:
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    I suggest that you obtain the DTC logged, to see what codes appear. I also suggest that you perform an engine tune-up, just to rule out the following issues:
    • replace iridium spark plugs (using only the correct model plugs), which have a 60K mile service interval
    • replace engine air filter if dirty
    • clean throttle body interior and throttle plate (black gunk tends to accumulate, which doesn't help the engine to run smoothly)
    • ensure that engine oil is 5W-30 viscosity and the oil level is not above the top dimple on the dipstick
    If all of the above is good and you still have a problem, then the engine ECU might be the issue. It is very interesting that the engine will stall, then restart on its own... I haven't heard that before. However given the market value of your car, it probably is not worth spending $$$ to replace the ECU - unless you can obtain a salvage unit.

    See the attached TSB that provides the current engine ECU part number 89661-47054. If you decide to obtain a replacement, I suggest you ensure it has that part number.

    That TSB also suggests checking fuel line pressure. The fuel tank and circuit opening relay are items to check.
     
  4. turboj91

    turboj91 Junior Member

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    2012 Prius
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    Patrick,
    Thank you very much for the informative reply. I will check on all mentioned. I know the oil situation is proper for now.

    Just to clarify a couple of things. When it stalls, it seems like it runs out of gas as it stumbles as it is shutting off. It will restart (not on its own like it is cycling) if I turn off the ignition, wait a few seconds and then restart. If I do not wait at least 5 seconds with the ignition off, it will not attempt to restart so I figured it may be an ignition relay that needs time to reset. I did not think of a fuel relay since if it is immediately attempted to be restarted, the engine will not even crank over. I am assuming that the ice will turn over and attempt to start even if there is no fuel pressure.

    This problem is the same no matter what temp the engine is or the outside temp. When started the engine goes to a high idle and then settles down. If I click to neutral the idle comes right down and the car does not stall. I do not need to leave it in neutral for a long period of time. Shift to neutral and then back to park and it is fine. I am assuming that the ECU reads the shift indicator going to neutral and what ever problem exists is bypassed.

    Other than this stalling issue, the car runs fine all day. Idles smooth, mileage has not suffered, power has not decreased ect... Simply no issues.

    I will do what is needed to be able to read codes. I will simply start the car and leave it in park and let it stall and see what codes come up.

    Again, thanks for your help. I will monitor if there is any more info posted and ultimately let you know when it is figured out.
     
  5. echase

    echase New Member

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    If you punch the gas after it has stalled what happens?
     
  6. turboj91

    turboj91 Junior Member

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    2012 Prius
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    Nothing. No restart. The ignition needs to be off for at least 5 seconds before it will restart.

    On thing I did not mention is if I start the ICE and then put it into drive ( or reverse) and accelerate slowly, it will stall and not restart unless I stop and turn off the ignition even if the gas pedal is "floored" after it stalls. Once it stalls, that's it. But... as mentioned, if I start the ICE, place it in drive and punch the gas and get the rpm's up past idle speeds, it will not stall and will continue to run fine.

    The ironic thing is, punching the gas gets the rpm's above the idle speeds and placing the shifter into neutral immediately brings the idle speed down to a low level and both of these scenario's bypass the problem.:faint:
     
  7. Flying White Dutchman

    Flying White Dutchman Senior Member

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    did you look at the HV battery state?
    is it dropping fast when driving .... maybe its keeps startig to recharge the HV battery because it bad?
     
  8. echase

    echase New Member

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    This may be a bad idea... but after a stall what happens if the HV battery drops below 2 bars?