Paul,

Could you detail exactly what you want MS to do?  If
that's clear, then a hardware/software config can be
specified to meet those needs:

Fuel Side:
# and type of injectors (low/high impedance)
Primary/secondary staging, or batch fire all four?

Ignition Side:
Stock 2nd gen ignition?  If not, what coil/ignitor
type is to be used?
Leading/trailing timing split needed?

Sensors:
- Stock Mazda manifold air temp and coolant temp
thermistors?  If not, what type?
- Stock CAS(Crank Angle Sensor), or custom
wheel/sensor?  If custom, spec sensor type.
- TPS is optional, certainly not needed for testing
purposes.  In MS world, it is used for accel
enrichment, and for triggering flood-clear mode.
Flood clear can be handled in other manners.  Accel
enrichment can also be provided using map signal
(rate-of-change of map, rather than rate-of-change
of
tps), which eliminates the need for TPS.

There are daughterboards being used by some rotary
guys to give a true 'plug-n-play' setup for use in
2nd
gen cars.  Given your application, this can be
avoided
completely.

If your spec is open, here's what I'd suggest:

Run stock high impedance injectors, or low impedance
with the stock resistor pack.  This eliminates the
need for the extra flyback circuitry you may read
about.

Use a stock 2nd gen CAS, remove the upper 2-tooth
wheel and its VR sensor, and grind opposing teeth
off
the lower 24-tooth wheel.

Buy an MS1 V3.0 based.  MS1 indicates the HC908
processor, while V3.0 indicates board revision.  The
V3.0 board has a number of improvements, one of
which
is the integral VR (variable reluctance) sensor
conditioning circuit.  This circuit will condition
the
noisy AC signal coming VR sensor in the CAS,
providing
a clean 0-5V signal from the modified CAS wheel.
Here's links to a couple reputable kit vendors.
Hopefully Yahoo doesn't mangle the links:

http://www.glensgarage.com/catalog/product_info.php?cPath=1&products_id=30

http://www.diyautotune.com/catalog/megasquirti-programmable-system-pcb30-unassembled-p-46.html

Use stock 2nd gen leading and trailing coilpacks for
ignition.

Once ready to run, drop me a line, or follow the
links
from msefi.com for the latest stable release of
msnsextra code.  This includes support for all the
features discussed above.

This will allow full ignition and fuel control, with
the minimum of fuss.  Given your background,
soldering
up a DB37 harness and wiring a relay or two will be
trivial, but the relay board might make the job a
bit
easier.

Hope that helps a bit.
Roger.


All I need is something simple to work on the dyno.
Turbo charged 2nd gen engine. Ignition is not
mandatory as
I can lash something up that will fire both plugs 20
dgrees
BTDC. I can go with the CAS or build an RX8 style
trigger wheel and pickup. I am using stock 2nd gen
injectors.

I ordered the bare boards from DIY.

Is msnsextra code C or 68HC908 asm source?

BTW I am thinking two of these could be used in an
airplane
with a 37 pin plug on the instrument panel. Unplug
one and
plug in the other as a preflight backup check. They
are cheap.

Paul Lamar ...No rotor no motor.

msnsextra is asm.  Latest version, and source, is
available in the zip file found here:
http://megasquirt.sourceforge.net/extra/files/

Stock 2nd gen injectors can be either high or low
impedance depending on year, so you may want to check
to see what you've got.

Roger.

Thanks for your help Roger.
No problem with the injectors. I can figure it
out. Thats what ohmmeters are for. I spent 20 years
manufacturing electronic test equipment. I have some
injectors I probably need a few more.

BTW where is the s record file for the extra version?
Also where do I get the assembler. Is Motorola
giving it out for free?

Paul Lamar


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