Hey chaps


Im hoping you can help me, I should have checked before i took the car off the road.

I need to know what the Tach/RPM output (blue wire) signal looks like from the igniter...

Can anyone tell me;

Voltages, freq (at RPM), what type of wave .etc, preferably a waveform if available! Thanks in advance!!!


Chris

 

Okay, answered my own question.

The RPM signal comes from the ignitor as you may know. Its output is a 12v (weird huh) square wave- had to proper screw with my function generator to offset the voltage that high. See table below;


1000RPM = 30Hz
2000RPM = 60Hz
3000RPM = 90Hz
4000RPM = 120Hz
5000RPM = 150Hz
6000RPM = 180Hz
7000RPM = 210Hz
8000RPM = 240Hz
9000RPM = 270Hz


The vehicle speed signal comes from the VSS itself. I replicated it with a 5v sine wave, i didnt test for a square wave as it didnt matter to me..

10MPH = 20Hz
20MPH = 30Hz
30MPH = 40Hz
50MPH = 60Hz
70MPH = 80Hz

As you can see it is Actual Speed + 10..

 

Hahaha a post that answered itself!