Wiring on my mini was tricky due to it having and engine conversion. Had some trouble getting the tachometer to work, as it was second hand off eBay, was wondering if it was the wiring or the part.
Testing a tach with a signal generator is possible but they are pretty expensive so I did it using an Arduino. Can read more about them here.
I used a Arduino Mega 2560 which costs about £6 from either eBay or Aliexpress, cheaper ones like the Uno R3 would also work.
Load the following code onto your Arduino
void setup() { pinMode(9, OUTPUT); } void loop() { tone(9, 33.3333333333333); delay(2500); tone(9, 66.66666666666667); delay(2500); tone(9, 100); delay(2500); tone(9, 133.3333333333333); delay(2500); tone(9, 166.6666666666667); delay(2500); tone(9, 200); delay(2500); tone(9, 233.3333333333333); delay(2500); tone(9, 266.6666666666667); delay(2500); noTone(9); delay(2500); }
Then ideally wire your tach to 12v and ground, and then pin 9 on the Arduino to the signal wire for your tach.
If you don't have a 12v power supply available you can use the 5v and ground on the Arduino, it will just read too low, that what I did.
And here's what it did youtube