note: a 470 Ohm 0.6W resistor also included
220 uH for RPM output "inductive pullup" (0.7A 9.5mm x 12.5mm marked 221)
If your RPM gauge originally got the input signal directly from the primary side of the ignition transformer (common for cars that originally had distributor ignition), or you know that the RPM gauge likes high voltage. Since 1989 most gauges are fine with the recommended EC36pin4 (p259/0) pulled up (to +12V with 1k .. 10k), but for example on old (older than 1989 ?) BMW was NOT sufficient to drive the tachometer gauge:
Take a free ignition output (IGBT based, not logiclevel !) and connect it to the input of the RPM gauge. Beware that injector FET or other output is not suitable, would be ruined immediately!!!.
We used EC36pin10, that is i259/7 as seen on GenBoard/Manual/DigitalOut/Table), configured tach_channel accordingly and used an "inductive pullup" to (switched) +12V made from a 470 Ohm and 220uH connected in series.
The inductor will make high enough voltage (up to appr 380..400V) to satisfy the RPM gauge. Don't touch it because either you or your family will be unhappy. The 470 Ohm resistor is to limit current if the output is enabled for too long due to misconfiguration or very low RPM.
Note: The 220uH value is NOT for the onboard "main supply filter" (could be overloaded by the 4 stepper outputs if total draw from +12V side exceeds 0.5A )
1.5 uH (5.4A 9.5mm x 12.5mm marked 1.5)
Probably only useful if you build your controller yourself and lost the "supply filter" inductor from the rescue-kit. 1.5uH value is NOT for the "RPM output inductive pullup".