OBD-II usefulness: Yes!

[Daniel Burk]

I get the privilige of working with the OBD-II diagnostics protocol on
my data acquisition system at work.  This protocol offers much to the
DIY'er, including a 25msec refresh rate for your data (under certain
circumstances).

On the 1997 and 1998 GM 4 cylinder applications (Excluding Saturn),
there are approximately 255 different parameters that are directly
available to the engineer.  They are accessed via "Parameter I.D."
codes, known as PID's.  You can define a "Dynamic PID", which is a
packet of six bytes worth of PID's.  Some of the PID's represent
conventional information that we are all familiar with, such as RPM,
Throttle position angle, and vehicle speed.  Other PID's that are
available include:
	Injector pulse width for each cylinder
	Ignition timing angle
	Current transmission gear
	slip angle of the torque converter
	calculated torque output of the engine.

Notice that last one:  It is calculated from the line pressure inside
the  transmission, and the slip angle of the torque converter.  Does
that sound like an in-vehicle dyno, or what!?

	Who says that OBD-II is mutually exclusive with performance?

	You just gotta know where the parameters are located!


	Cheers,
		Dan.