Current status: Igniton EMI from 1986 distributor causes driveability issues. Currently upgrading to coil-on-plug to mitigate EMI.
Firmware Build tools:
- Visual Studio Community 2013 (free) with Visual Micro.
Interface to the Firmware:
- The Arduino serial monitor
Engines supported:
- 1984 VW vanagon gasoline "digijet" (in development)
Control Inputs:
- Stock 1986 distributor for hall-effect signal without mechanical ignition timing
Control outputs
- Injectors : Batch-fire (same as 1984 stock)
- Ignition: ECU controls timing of single coil (with distributor)
- Currently developing: Coil-on-plug system
Auto-tuning
- Adjusts engine map while running (this is unusual among aftermarket ECUs)
- Both global and local (on the map) fuel adjustments happen simultaneously.
- Map changes not permanent unless saved.
- O2 sensor type: narrow-band (1984 stock) O2
I see this is a couple of years old and I hope I'm not out of line here because I'm new to Arduino so much that I know almost nothing but I do something about engines. I don't know if anything you are doing with your project could be part of your "missing" problems but everything you've written along with your smog sheets indicate a classic vacuum issue. Your VW uses a return fuel system and experience would have me starting there. Its parameters are not forgiving and your project is about fuel. From there I would test the block gases recirculating to the intake. If you have AC consider if there is any possible relationship to your missing and AC. Off hand I don't know of any OEM ECU where AC monitoring\sensing isn't integral to fuel delivery. You also mention coming out of curves. Your VW power steering also effects vacuum. Off hand I can't tell you anything about the testing involved but it's based on the greater the steering wheel rotation, the more drastic effect on vacuum along with a more adverse effect on engine performance. Cost effectiveness has led to a lot of system integration that really should not have been used. Vacuum is an obvious cost saver with integration but it also leads to a lot of obscure sources for creating problems.
You've also brought up heated oxygen sensors. You haven't mentioned how much access you have to OEM program parameters but there are some controls here you can play with to fool or cheat OEM programming to accept out of range temperatures as normal. This will not be acceptable for your emission testing requirements though.
Just some thoughts here for your project.