my first ms turbo3 attempt required me to spoof a 6 cylinder tune as 3 cylinder operation is very limited on the ms2extra firmware.
i deleted the distributor and ran a 3 channel ignition using outboard ignitors from the suzuki g13b dohc 16 valve system and 3 cop units from a ford v8. the ms was set up for batch fire and initially i used the typical crank mounted 36-1 trigger wheel and v/r sensor.
i ran into problems with the v/r sensor as it acts like a generator and would produce a signal at idle that was pretty much low enough to be "in the mud" while producing a nearly 70 volt amplitude signal at 6000 rpm. the high amplitude produced false triggers and resets that were very dangerous for a boosted application. i attribute that to the failure of my friend's 'squirted turbo3 - it threw a rod through the block and brought his project to an end.
i started researching this timing failure and came up with several things. to effectively use a larger set of injectors, 460 cc/min, to get the fueling headroom needed to produce my desired hp output i had to move things to sequential injection. to keep a v/r sensor from generating higher and higher voltages as engine speed increased i switched over to hall effect devices.
i came up with a hall effect gear tooth sensor for the crank and another proximity hall effect for the cam. i maintained the 36-1 trigger wheel on the crank and embedded a neodymium magnet into the cam gear with the hall effect sensor to set the valve timing phase with one pulse per revolution of the cam. i also used a couple of really tiny outboard hall effect signal conditioning boards. those allowed me to depopulate the ms board of all it's signal conditioning components and connect the digital (4.35 v) outputs directly to the ms2 daughter board's processor pins.
i used the jbperf 4 channel board to allow for 3 channels of injection drivers and as throughput for the 3 channels of ignition output to the outboard ignitors. that also allowed me to delete a lot of other ms main board components including the oscillator crystal. removing all those components from the main board allows the ms controller to operate at a much lower temperature as the heat that would normally be dissipated is gone from the enclosure.
that also allowed me to change the ms2extra firmware to sequential injection mode with direct 3 channel ignition retaining the 3 ignitors and 3 cop units. i blanked off the distributor drive port. now i can control the injection with a squirt at the proper valve timing instead of a batch firing arrangement which helps a lot to manage the engine's idle point. another benefit is that sequential injection opened up some previously grayed out tuning applets allowing me to apply trim to individual cylinders. that lets me provide fuel enrichment for the #2 cylinder which generally runs hotter than the 2 outboard cyclinders. overall, fueling is more precise and idle control is way better.
indeed, the simple injector mounted on the intake manifold is a cold start injector. on some of my turbo3 engines i used that injector to provide extra fuel at wot. on my current turbo3 engines using ms2extra management, i have removed the cold start injector and installed a blanking plate. you do not need the cold start fuel enrichment injector with the ms controls. the simple 2 wire idle speed solenoid driven by the basic onboard idle circuit works fine along with the basic cold start fuel enrichment provided with the tuning software. i installed a small hose nipple in the blanking plate and use that as a port from which a better average of manifold boost/ vacuum can be read. i use a hose from that port to a block type manifold to distribute the same boost/ vacuum signal for the ms2's onboard map, my vaccum assist on the bov, and my afr gauge. using the manifolded single point port makes all my instrumentation operate off of the same signal as a standard.
i use tuner studio with the $40 licensing to open up the logging and auto-tune functions.
so, i recommend designing initially to run sequential injection, hall effect sensors with outboard signal conditioning, and a distributorless ignition.
if you are hell bent on using the distributor, i highly recommend our member fainya as a source for rebuilding your distributor. he has a fully complemented machine shop and can perform all of the service required to bring back your worn out distributor. and his service is really affordable.
i documented a lot of my megasquirt/ turbo3 stuff in my blue monster thread. it's a lot to read but.....
good luck with your project.