Need help to get this “nice” jap trigger working
Cas distributor 4 spots on shaft
- tooth width == 180 crankdegrees ?
Primary trigger input setup
- input DC voltage measured with input open ?
- input DC voltage measured with input pulled to ground with 1kOhm resistor ?
- ECU serialnr ?
- can you temporarily place a magnet on a crankwheel and use a HALL sensor as reference, confirm with scope ?
- it's sometimes difficult to make a proper permanent sensor mount but perhaps not very demanding to temporarily mount for verification in the garage
Ign output setup
When setting up ignition to 17 degrees BTDC at 1000 RPM, its only 7 degrees at 5-6000 rpm so its sliding almost 10 degrees. Measured how ?
- Seen this problem long time ago but due not remember what caused it.
- capacitance on input causes appr 278 usec delay on input ? - this can cause the said delay at higher RPM. Can you try the primary trigger falling edge ? Can you scope the input signal ? If this is the case, you can decide to shape input signal properly, or if it's perfectly reproducible, just compensate
- wrong edge of output ? No, that would be too MUCH sparkadvance at higher RPM
- tooth width?
- 180 crankdeg, seems good
- does validate warn about strange values ?
- apparently nothing relevant
- is RPM smooth (or fluctuating) ?
- MAYBE TIMING LIGHT triggering on wrong edge ?
- is it a smart timing light ?
- Logiclevel coil ? Maybe the coil firing on the wrong edge ?
- maybe the wheel changes position ?
- cambelt sloppyness + mechanical hysteresys ?
We scoped on bench, ignition is exactly as shown, no "sliding" at higher RPM.
Write (above) about coils, check carefully that
- coils fire on the edge when output is deactivated (after dwell), not automatically earlier (eg internal current-limit ??)
- that strobelight measures actual spark (not the dwellstart ~ activation of ign output) and that
- strobelight does not have some special compensation (it actually lights up exactly at spark, no compensation)
- is the input not sharp enough ? Fill in above
Triggerlog 1 17 degrees
Triggerlog 2 27 degrees
Log (Config missing)
Bench Testing Results
We benchtested your setup today with 1.2.6 firmware and scope. It behave perfectly, we didn't find any "ignition sliding"'. Ignition seems to fire at good times at any RPMs.
For example at 1000,3000 and 5000 RPM (with sparkadv locked to 25 BTDC), ignition angle is ~55 degrees (TDC after the trigger is 80, so 80-25=55) as calculated.