This Audi 5 cyl (20VT) engine has a home-made custom 10+1 trigger (5 pins on crankwheel).

Such installs are usually problemfree (and installers don't care to document publicly).

Page created to summarize that (thematically, not chronologically).

ECU serialnumber v3/6110

Primary trigger

Secondary trigger

During cranking the [trigger log] looks really good with 10 pulses on primary and 1 on secondary

but when it starts it gets "missing tooth" signals, too many pr tr and too less primary trigger. I've logged the two events.

I'd took some pictures for you to see. Could it be that the crankshaft puts out the signal when the engine starts?

Not impossible, but would be nice to see 2 occasions captured (a triggerlog and a vemslog also). VR trigger is primary candidate, check polarity (both primtrig and sectrig) at least with the DVM DC mode and "pull-away metal" method, or best with oscilloscope !

The car was running with VIPEC before (same trigger? Yes, and no. The Sec trigger is the same, but the primary was changed due to badly treated sensor and no trigger signal) and no problems, so it has to be in the ECU or maybe just some tuning problems?

coil option is good

> Number of teeth = 10

> first trigger tooth = 0

> next trigger tooth = 2

> Angular width = 72

> Reference tooth (order of arrow)

> 0

> 2

> 4

> 6

> 8