Autosport Labs

In
http://www.bgsoflex.com/mjl/mjl_edis_summary.html
the SAW signal rising edge is aligned with the falling edge of PIP..

..but in
http://www.picotech.com/auto/waveforms/ford_edis.html
it is shown as being almost completely asynchronous

I see in the MJLJ software that 'alignment' is attempted by setting the duration of the SAW according to the last but one PIP duration. However this still means a small delay between falling PIP and rising SAW since the processor takes time to set up the timers correctly.

Does this delay matter, and how long could it be - or is it immaterial and the EDIS doesn't really care when the SAW pulses arrive (as long as they do, otherwise it goes into 'limp mode')??

The EDIS doesn't care what the delay is between the PIP and the SAW as long as the SAW occurs at least once every 6 PIPs. If the EDIS doesn't see a SAW in that time it reverts to 'limp mode' fixed timing. The Megajolt however doesn't measure this time as part of the crank period, so if the gap is too long then the RPM accuracy will be affected. The gap would have to be pretty big for this to be noticeable though.