Hello

It seems my leading ignition coil died (im running old-school distributor setup as I have a FB). It seems I was very unlucky in that it died as I changed from ms2 standard firmware to ms2/extra which is why I thought it was the firmware giving me problems. I swapped the leading coil for the trailing and she fired right up . Ill be getting a new coil asap for the trailing. Im running fuel only so im using a coil- tach signal to trigger the MS. I'm getting some rpm spikes. I see on the site that for rotaries running OEM coils I should use a 50k ohm resistor for coil- tach signal to prevent spikes. Where must I use this resistor or which resistor must I replace? From what I can see on the assembly guide it is either R12 or R13 if a resistor needs to be replaced. Or must I just run it in series into the tach input wire to Db37 pin#24?

Also, I have a 47k Ohm (1/8 watt 5% carbon) resistor left over from the MS assembly. Could I try this first before trying to source a 50k one?

Thanks

 

The resistor goes in series with the ignition pickup. 50K is not always the ideal value. Generally in my experience between 20 and 30K does nicely. Just make a little sub harness that connects between your coil and ignition pickup wire so you can easily experiment with different values.

There's not a whole lot of current in the tach circuit, but 1/8W is too small.