Paul,

I am doing research on megasquit and am trying to understand how the 2nd gen
is set up for ignition as well as fuel injection.  The 2nd gen CAS setup has
2 wheels and 2 sensors that supply crank angle 26 teeth wheel and ingnition
2 teeth wheel to the ECU.  Megasquirt uses these signals also.  I cannot use
the CAS as I need the space.  How does the 3rd gen trigger wheel set up
work?  Can I duplicate the 2nd gen CAS on the crank hub? Thanks for any help

Joe Berki
Limo EZ

The second gen CAS runs at half e-shaft speed so it has two
trigger tits. That means it puts out one pulse per revolution
just like the 3rd gen and RX8 engines.

It also has another signal the 2nd gen computer uses for
spark timing. The 3rd gen and RX8 computers don't need that
data. All they need is one pulse per rev. The computer decides
when to fire the plugs and inject fuel.


"Okay, now that MegaSquirt® knows how much fuel to inject, how does it know when to inject the fuel? That is a function of the ignition input circuit. A signal is taken from the distributor or negative terminal of the coil. Ideally, there is one spike each time a cylinder fires. MegaSquirt injects fuel on even multiples of these signals."

As far as I can tell without reading the code it needs a trigger
every time a spark plug fires. That means it is dependent on
the ignition system used. I think. Perhaps some one on here
can clarify.

Looks like the first thing you need to do is decide on an ignition system.

Here is a simple system that will work for an ignition system compatible
with the mega squirt.

It is manual advance like the Model T. All you need is two Hall
Effect sensors one for the front rotor and a second 180 degrees
out for the second rotor. You need a buffer amp on the hall effect
sensors (CD4050) so they  can send a pulse to both RX8 coils and to the Mega squirt.


Paul Lamar