01-03-2018, 01:54 PM
Happy New Year Fixkick!
My question today is about the old 89 Sidekick ECU which uses a tachometer monitor input.
When I looked at your tachometer circuit explanation page, you showed that the tachometer signal wire, from the - coil and after passing through the noise suppressor circuitry, still produces a signal waveform with a 50V back EMF spike.
Does this mean that:
(1) the tachometer in a 89 Sidekick is able to measure the frequency of 50V spikes, and this signal directly makes the analog tach gauge needle move?
(2) Or is the tachometer equipped with some sort of additional digital filter circuitry that converts the spiky signal into some sort of 12V square wave for a digital tach gauge to process and move the needle?
Thanks for reading!
My question today is about the old 89 Sidekick ECU which uses a tachometer monitor input.
When I looked at your tachometer circuit explanation page, you showed that the tachometer signal wire, from the - coil and after passing through the noise suppressor circuitry, still produces a signal waveform with a 50V back EMF spike.
Does this mean that:
(1) the tachometer in a 89 Sidekick is able to measure the frequency of 50V spikes, and this signal directly makes the analog tach gauge needle move?
(2) Or is the tachometer equipped with some sort of additional digital filter circuitry that converts the spiky signal into some sort of 12V square wave for a digital tach gauge to process and move the needle?
Thanks for reading!