This Mitsubishi has a HALL trigger on the camsync.
unfortunately
- resolution is trash (due to cambelt sloppyness)
- period is same as if it was on crank (less information than normal cam signal: not enough for fully sequential, but enough for wasted spark)
The trigger is Coil type (one pulse per event ), but alternating positive and negative to distinguish 1-4 and 2-3 cylinders (are you sure?).
Every spark belongs to a step on the figure below. DC: ~2.5V, amplitude: ~2.5V.
Somewhere we apparently have a a series capacitor (input highpass filter !!! ) that causes the very characteristic sharktooth signal.
- maybe in the notebook: I recorded the trigger signal with a notebook
The signal is currently processed with LM1815 and series condenser so it is theoretically universal considering trigger type (hall and VR). In 50% of cases, LCD displays right value, otherwise rough half of proper RPM.
if we reconstruct the original signal, we can see that
- pulse for cyl1,4 has a longer width
- pulse for cyl2,3 has a shorter width
Find the correct cyl:
- camsync
- using bothedge (no LM1815) and consider signal length (firmware modification)
Any ideas, how to condition the signal?
- try swapping the 10k pullup inside v3.x : use an 1M or even higher (eg. 1.5M) pulldown. The series cap will drop voltage very slowly with that value.
Check bottom of DocsPage to upload files to wiki.