Found that this only happens when a non existing trigger setup is in use, we were both testing with a plain 60-2 wheel trigger without camsync, and tried to use more outputs than possible with this setup.


The changing behaviour is related to early_dwellstart function, and wont affect anyone in a car.


Exactly, this is OK. Without camsync, +-360 degrees cannot be detected, it's only possible to drive wasted spark! It's actually because of: multitooth.c syncronize_igncount() function

if( engine.ignstate==0 ){


IGN output behavior changes with RPM and # of cylinders.


I found this issue when attempting to functional check a unit prior to configuration. Initial reports suggested that it was a bad trigger signal (benchtop generation). Resolved this problem and now can generate a proper 60-2 wheel VAG style without any wheel count errors.

mcel.. if you change your IGN outputs to 00 01 02 03 04 05 06 07 instead of 00 01 00 01 00 01 00 01 you can recreate the behaviour with your config - yes, but 60-2 without camsync I can only use wasted spark (2 ignition transformers, not 4!)

Description of issues

Current experiment

Reflash VEMS v3.3 with new firmware 1.0.23 first then use the latest release.

Firmware version 1.0.23 as downloaded from filethingie

Problem is that the number of outputs driven changes when a factor of RPM and # of clyns and #of IGN outputs selected

Original configuration to find problem

Basic description is the Ingnition outputs were set in

Ignition Settings

Outputs to use in h[2] set to [7..0]

Yes I know this is not valid for a wasted spark BUT, it produces bad output.
  • above 41Hz(~2500rpm) with an 8 clyn setup. Note that another_trigger_tooth=1E doesn't seem good for 8cyl. Please provide all the configs you used.
  • above 29Hz(~1650RPM) with a 4 clyn setup
Symptom above these values all IGN outputs that are set are triggered else only 2 outputs are triggered.

if Ignition Settings

if Ignition Settings

if Ignition Settings

if Ignition Settings

Emils report

triggering the board at 2000 rpm, trying to reproduce GRMracers report of strange ignition outputs

2000 rpm, 60-2, tried with ignchmax = 03 or 07, same result

based on marcell's example config