First thing to address is the trigger. The signal is taken from the Jacobs + distributor trigger, and here's the 0.76 Volt square-wave signal:
How to read this safely?
0.76V is a bit too low for a HALL setup. It might work, with some experimentation:
- try a strong pullup: 1kOhm to 5V
- try a voltage divider: distributor_signal - 270 Ohm - (ECM HALL input connected here) - 2k Ohm - +5V
If this does not help (try to play with the values, eg. try several values from 1k to 4k7 instead of the 2k resistor).
Shaping the signal with active components (transistor, inverter, amplifier) is probably not justified.
VR setup
VR does not require high amplitude, but requires the signal to go under 0V. A series cap is necessary. Min 10uF 25V
- eg. the 1210 size cap in the GenBoard/VerThree/RescueKit could work
- or a bigger throughole
- or several capacitors in parallel.