MoTeC Global Forum

With my 20yo 2-Group, which was wasted-spark & for which I wasn't using REF+SYNC, you couldn't set the ignition timing such that the cylinder would spark before the timing-signal the ECU was getting. Or at least, this was what I was told.

Looking at the M84, and I think I have this right, the CRIP is the number of degrees of crank rotation to TDC from the first REF signal the ECU gets after it's SYNC signal. So say CRIP is 40 degrees. Is there a limitation that I therefore can't set timing to 41 degrees BTDC? Or can the ECU know from the frequency of the REF signal that the next revolution would be 41 degrees BTDC and hence calculate such that the spark will be triggered 1 degree before that "first REF signal the ECU gets after it's SYNC signal"?

To answer you question there is no limitation on firing point. The ECU works out which crank tooth is nearest to the required firing position and then times from there in the case of the 2- group.

For the M84 Ignition firing is worked out different ways based on the REF/SYNC mode is used.