So, I've been busy selling off some of my cars, and haven't really been giving this project as much time as I'd like. But, I managed to finish the wiring harness and start the engine this week. I've updated the wiring diagram in the first post to reflect the current configuration. After the successful start, I'm taking some time to reconfigure my engine stand set-up so that it will be less ad hoc during the tuning phase.
Here is an overview shot of the engine as it sits this evening:
I ended up going with pencil coils on plug from a 2003-04 Honda CBR600RR motorcycle. I used a Bosch 0 227 100 211 igniter from a late '90s / early 2000s Volkwagon to fire the coils based on logic-level waste-spark signals from the MicroSquirt board. They are so low-profile:
For injectors, I used 19#/hr units that are much cheaper when you buy the rebuilt "Ford" versions on eBay (p/n 0280150943). I discovered that you can't re-pin the OEM AMP connectors in the BMW harness, so I bought new AMP Junior Timer Power connectors and terminals from Mouser for both the injectors and the ECU temperature sender:
Here is the PWM-driven idle air control valve, from a Geo Metro / Suzuki Swift 1.0L engine, mounted to a boss under the intake manifold. I am honestly not sure if it's working. The open-pipe first run was very loud and necessarily brief as I have no radiator installed. it remains to be seen whether this can move enough air to control the idle:
Here you can see the throttle body, TPS with adapter from 02again, and GM air temperature sensor (next to the dip stick):
I had the wiring tidy for the start, but then jumbled it in moving the engine around the shop this morning. I need to create a little panel/console to mount everything to so that everything remains orderly:
That's the news for now. The first start was so easily achieved, but the real work is really in this next phase of tuning. Especially given that while I am experienced with building wiring harnesses, I know next to nothing about tuning MegaSquirt.