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Crankshaft position sensor gear

Discussion in 'Gen 2 Prius Technical Discussion' started by FirstFlight, Mar 29, 2011.

  1. FirstFlight

    FirstFlight Member

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    Location:
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    2005 Prius
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    Does anyone know how many teeth are on the gear that the crankshaft position sensor reads?
     
  2. FirstFlight

    FirstFlight Member

    Joined:
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    Location:
    New Jersey
    Vehicle:
    2005 Prius
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    Well, Hobbit's information is really great. I was kind of hoping that I could measure RPM from the crankshaft position sensor but his information states:

    The 1NZ-FXE mill in the Prius uses a "36 minus 2" crank wheel, i.e. 34 teeth
    with a gap where two more teeth are missing. This conveniently maps to 10
    degrees per tooth slot. The ECM syncs up with the base timing rate of passing
    teeth and then looks for the missing pulses as an absolute reference as to
    where the crank is. The cam "wheel" only has three teeth on it [at 90 degrees,
    thus a "4 minus 1" configuration] and works similarly. Here are some pictures
    of the real things, courtesy of Galaxee from Priuschat and her husband who
    spends his days armpits-deep in this stuff and brings home all the coolest
    discoveries.


    So, this is a problem but could also help me in another way.

    If this has power whenever the "ready" light is lit, then for sure I'd be able to get the "engine spinning" mod done.

    However, if I wanted to use this to calculate engine RPM, those two missing teeth would be an issue. If I took the measured frequency/36, there would be two pulses missing. If I took the measured frequency/34, it wouldn't be entirely accurate.

    Maybe if I take a snapshot every 200mS I can calibrate it.

    I need to think about this for a while.....