I was thinking about this in regard to the post about fuel octane... We've had a lengthy discussion a while back about the various ignition curves contained in the microplex but I was reviewing the posts and I didn't find/don't recall if we ever determined if the microP simply has a selection of curves built in and that one is selected for wherever the car was delivered - US or Italy, for example - or whether some of the curves are actively selected by the computer based on operating conditions. A year ago, based on Brian's (Rifledriver) info, I lifted the Microplex pin 17 ground to change the US curve to the base (Italy) curve and posted a bunch of info about that. But I still don't really know if there is any active engine management going on or if the system is just basically "hard wired" to produce whatever fixed curve is selected, just like a conventional distributer would. So...does the MPlex actively change curves based on operating conditions or does it just deliver the fixed curve determined by what wire is connected to ground or whatever?
You should say "map" not "curve". The MicroPlex map (advance vs RPM vs intake manifold pressure) is selected by the pin grounding scheme. The operating position (the advance) on that particular selected map is then determined by using those two engine parameters.
Thanks Steve - so the basic map (whichever one is selected by the grounding) can vary somewhat based on the sensed operating conditions? Also, as far as I can tell, there is no knock sensor in the system, right? So would the ability of the system extend to being able to advance/retard the timing based on the fuel being used? Modern systems can do that within limitations of their programming so that if the engine is designed to run best (most power) with 93, putting in 87 will cause the timing to be retarded. I assume the microplex has no such capability...
The map doesn't vary (when warm), just where you are on the map based on RPM and intake manifold pressure. However, there may be different maps for warm vs cold for each pin configuration. Correct, no other sensors are present than the flywheel sensor (RPM) and intake manifold pressure sensor inside the MicroPlex unit itself (I'm not sure if the WOT switch being closed vs open does something too -- i.e., WOT switch talks to injection ecu which talks to ignition ECU).
