Engine runs, but config needs review.
Engine Type
- SR-20 DET, Nissan GTI-R, Pulsar in USA
"Nissantrigger 360+4"
4cyl
- secondary trigger: 360 pulse
- HW divider was NOT used, simply connected the 360 pulses to sectrig HALL input.
- primary trigger: 4 pulse
- the length of pulses on this engine is something like 2,2,2,8 which DIFFERS from the original specs (the wheel we got and the patent) the 360 tooth trigger was made for originally .
- So we were lucky that we could still get 1.1.x firmware to sync (perfectly): even without sectrig HW divider, we had to enable the "divby 4" flag in config which means "sync to a primtrig tooth that is longer or equal >= 3 sectrig pulses" even though we did not use divider on sec
- was triggerlog captured with primtrig rising or falling ? (write rising or falling in the filename next time).
symptoms:
- Fw-97 no rpm doesnt work
- Fw-98 RPM-reading fluctuates (same result on all 4 cases: prim, sec rising, falling edge).
- cyl1,4 ign is OK,
- but cyl2,3 ign is 20 degrees off (advanced?)
- with per cyl spark delay it can be fixed, but RPM-reading still fluctuates
To check:
- primtrig rising or falling edge
Most likely edge related
- Either the choice of primary trigger edge
- or the assumption (from available descriptions and patent) at the time of implementation was wrong
- even with a real disk, the direction of rotation can be wrong and the polarity of nissan HALL also could be uncertain.
We're investigating this but still no proper info:
- primtrig scopeshot would be highly welcome
- even with soundcard
- even DVM voltage measurement of primary trigger (with running engine) would be some info about polarity.
[1.1.99 2012-03-15] has firmware mod to apply for all known types of 360 sectrig-pulse nissan triggers
- polarity
- primtrig=rising must be configured in config of course
- always count sectrig pulses when primtrig=high
- secignore to adjust window-toothcount threshold.
- recommended threshold values: >4, >9, >13, so start with secignore=4 for this engine
- because max window can be 8, 12 or 16
- in safe mode (eg prohibit byte screwed or ibutton not touched), corr.air shows the detected peak window-length+128 to aid the user count window-length without scope (VemsTune developers might make a wizard for it).