Spark Ionisation to determine Combustion Characteristics

[MaxBoost at aol.com]

>As far as I know, this is a current (no pun intended!) method for 
>misfire detection for OBDII, although I don't know who or if anyone is 
>using it.

>Andrew Rabbitt
>Orbital Engine Company
>PERTH, Australia

FWIW, On OBD-II cars Nissan uses a secondary crankshaft position sensor on
the outer lip of the flywheel to watch the crank speed to detect a misfire.
 There is a second row of teeth (360) next to the ring gear.  By watching for
a smooth pattern it can detect when a cylinder drops out by the change in
speed.  It also knows which cylinder misfired  by the #1 reference at tdc for
#1 cylinder.

Max.