GM Optispark

[Jody Shapiro]

On Sun, 17 May 1998, Bruce Plecan wrote:

>   On the optispark how many pulses are there per crank revolution?.
> Is there a reference pulse?.  

There's a hi-res and a low-res signal that comes from the Optispark.  The
Opti is driven off the cam and there's 4 pulses per crank revolution
(low-res) and 180 pulses per crank rev (hi-res).

> Anu one know of an on-line picture of this set up, "wheel" sensor,
> or what ever they got in there for crank posistion.

http://www.charm.net/~mchaney/optisprk/optisprk.htm

The 96/97 cars have a seperate crank position sensor on the crank itself
for measuring crank velocity (for OBD-II misfire detection).  One neat
thing is that the PCM can detect timing chain wear/slack by comparing the
the crank position sensor to data from the Optispark. 

-Jody
--
97 Blue Vortech Z28 -  Best ET: 13.100  Best MPH: 111.24 (Goodyear RS-A's)
361 rear-wheel hp @ 6000rpm,  359 rear-wheel ft-lbs @ 4400rpm
http://www.bit-net.com/~jshapiro/z28/