MembersPage/Iwbs (2015-06-17 12:09:37)

Audi URs4, 20VT, AAN engine

Problem is that triggerlog shows no secondary trigger or spark events. As well as no RPM while cranking. Primary trigger seems fine.

At the moment everything is stock, besides VEMS V3.6 and NTC type IAT sensor. Running firmware 1.2.2

Thanks for the [vemslog, config. and triggerlog], we reviewed. See below.


Hello Iwbs,

I have reviewed your config and triggerlog, indeed no secondary triggers present.

Lets start with the basics, how have you wired up the trigger part of the ecu (e.g. which sensor is connected where)?

My investigation shows this board (not assembled ecu but main board only) with serial v3_u009467 was sold to a reseller who must have manually assembled the ecu himself, i would advise you to contact the person you bought the ecu from, most likely there is some board setup error; in any case he should be able todo bench trigger testing for you to confirm good ecu operation.

Best regards, Dave


Just INFORMATION (in this chapter nothing to do): auditrigger HALLscope is a convenience feature of v3 when sold as [VEMS ECU]

Only available with auditrigger w/camhall inverter:

ECU (sectrig=auditrigger w/camhall inverter) originally ordered as assembled is set up that way (unless requested otherwise)

[mainboard] (assembled by reseller) so we cannot tell if the auditrigger-HALLscope feature is available (internal p259 channel wired for camHALL-scope feature ; or even if it was assembled with auditrigger-camHALL-inverter or without)
  • it does NOT effect normal operation at all; just debugging: cam-HALL sensor needs to be unplugged (as a test, if no sectrig pulses in triggerlog, and new triggerlog captured), read below

IMPORTANT: Before sending device anywhere:

in case of any auditrigger sectrig issue, capture 2 triggerlogs : one with camHALL sensor disconnected; and one with camHALL sensor disconnected, and one with signal wired to GND:

That is very easy, and either it confirms the ECU has camHALL inverter, or if it is without camHALL inverter (both will work for an AAN, unless the flywheel is alien, donated from a 7A engine which has some "ghost ferromagnetic anomaly").


optional (but useful): Verification of internal pullup (with DVM: 5 minutes)


If still no sectrig pulses in any triggerlog (captured with camHALL=hi and low), than crankhome-VR setup must be reviewed carefully.

Thank you for your help!

Today I tested camHALL sensor itself with DVM and scope. Scope showed me no trace of it. Measured voltage between sensor signal and ground while cranking the engine and it stayed 0V. Absolutely no changing in voltage like there should be.

I will try another HALL sensor and see how it goes. Also I have camHALL sensor mounted right under the exhaust cam pulley, so there's no way it could've turned away from the crankhome position.

Power feed to the HALL sensor was 4,9V. That should be enough, right?