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).
- This install has stalled: installer needs to verify polarity of primtrig VR signal (and likely polarity swap is needed) before any further progress
- a scope would be very desirable to see primtrig-VR pulsetrain
- also don't forget to upload vemscfg, see FileArea
ECU serialnumber v3/6110
Primary trigger
- VR, 5 pins on crank
- POLARITY IS UNCERTAIN, MUST BE VERIFIED
- GenBoard/Manual/VrSensor/Polarity
- InputTrigger/RunOut can be a problem if the amplitude of pulses vary by large. (the noise suppression feature of LM1815 treats a tooth with 75% amplitude as noise after a 100% amplitude peak, which is good for good pulsetrain but hurts for sloppy toothtrain... can be disabled by "allow very sloppy wheel on primtrig=VR" in order comment (R181 would be made higher).
- for sectrig that is often sloppier more room is allowed (R182 > 150k) by default, but for primtrig a relatively even aplitude is usually the case so the default noise suppression is used unless explicitely requested otherwise.
- good signal with good polarity makes falling edge cleanly pass over 0.0V as "Geber for Zündzeitpunk" on InputTrigger/AudiTrigger
Secondary trigger
- just HALL, 1 pin on cam - Audi original from AAN (behind the cam pulley).
- NOT auditrigger ( which would be sectrig crankhome-VR masked by cam-HALL)
- The trigger has been used before in the same setup without problems.
- with v3 that (LM1815) uses the falling edge of VR sensor signal ? Or with VIPEC ? It worked with VIPEC.
- in any case, we can settle with "it worked before" and stop thinking about it. Or, start to check things for both VR signals: DC voltage level, polarity (amplitude also if possible).
- (Unlike the 3B distributer), in the AAN the cam-HALL signal window is very unlikely to go away from the crankhome-VR pulse but the HALL should also be checked with scope. The HALL can also be measure with DVM (push the car in gear 5, max 4 meter needed for 2 crank rotations, take note of both 0V and 4-5V signal level and mark these 2 engine positions with a pen.)
- if sectrig signal is lost from triggerlog, cam-HALL can be disconnected and pulled constant as an experiment. (To GND if if ECU has cam-HALL inverter)
- a 135 tooth will attempt to start (at good position only about 4-5 times from 10 attempts) but a c010 will likely not even attempt to fire spark (but show sectrig pulse in triggerlog every 5th crankpulse).
- if sectrig signal is lost from triggerlog, cam-HALL can be disconnected and pulled constant as an experiment. (To GND if if ECU has cam-HALL inverter)
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.
The setup is original for the engine and the sensor is VR.
- That won't work until the trigger polarity is verified (likely needs swapping).
- for crankhome-VR it's most likely need reversing. See VemsAudiAan and InputTrigger/AudiTrigger
- for the 135 tooth the primtrig polarity does NOT matter, but for 5 pulses polarity matters and must be checked. GenBoard/Manual/VrSensor/Polarity
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?
- We benchtested V3 with 1.2.15 firmware, with these settings and it seems good.
- Note that vemscfg and vemslog wasn't provided by user, would have been reasonable to try with that.
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
