Fwd: eddy current brake

[Markus Strobl]

> I believe the new Corvette engine uses both cam and crank position sensors.
> Does anyone know how many trigger points are on the crank?  It seems that
> the big boys have decided that a crank sensor is necessary, the question is
> how are they determining position for ignition timing?  me

I have a '96 GM LT1 V8. It has the following sensors:

Crank trigger: 4 positions. ONLY used for misfire detection. This was first
introduced in 1996 with OBDII. 

Low res cam driven: 4 positions. Used for ignition timing

High res cam driven: 180 positions. Used for ignition timing. 

The low & high res are really just one sensor and then there's a little box
that makes it into a high res and a low res signal. The engine will run without 
the low res but it will crank longer before starting. 

A added bonus with the crank trigger is that the PCM can compare it's 
reading with the high-res cam signal and thus know how worn the timing chain
is. Pretty neat.

The wear factor (expresed in degrees) can be read with a scantool.


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Markus Strobl                1996 Z28 6-speed. Black/Grph. Various Mods
Dallas, Texas                http://www.allinfosys.com/fbody/markus.htm