Audi URs4, 20VT, AAN engine with non-factory assembled v3/9467 (purchased as mainboard and custom-assembled, non-standard in a couple of ways)

Installed camHALL inverter and [car finally started, without any problems] CONGRATS.. Thanx for cooperating and thematically sorting it. Have fun with your project (tuning, idle, power, gizmos, whatever...). If you happen to order another VEMS v3 ECU (econoseal, motronic55 or other type before 2016-07) (with your real name/addr we know from elsewhere), write in the order comment: "-150 EUR ... and refer to this URL."

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

Information from Peep (who was involved with assembly):

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 is normal.

• I tested again camHALL sensor, made some silly mistakes before testing it. As it turns out camHALL sensor is fine. Power feed stayed at 5V, ground is fine and signal changed from 0V to 5V. Tomorrow I will take a scopeshot to verify alignment.

  • forgot to say, that it's also possible to verify camHALL sensor output with DVM (DC voltage measurement), eg. moving the car in gear 5, and noting the position of window (and relating that to TDC, or the crankhome-VR pulse).
  • But of course scopeshot is the best: if captured with 2 channel scope, with crankhome-VR signal (alternatively with 1 channel scope 2 resistors, say 10kOhm each, can be used to mix the 2 signals).

● Engine won't start

Got solution for my trigger problems, (non-factory assembled) ECU was missing 10k pullup and that's fixed now, although it's still giving me sometimes errors less pr. trigger and tooth length bad even with injector and ignition fuses removed. There were no trigger errors when I removed spark plugs. I'm pretty sure this is not the issue anymore cause as long as I have reviewed other similar projects, engine should still start.

Tested my ignition order in vems test mode and it was 1-2-4-5-3 like it should. Also injectors were tested in test mode and they all open and close. Pulsewidth while cranking is about 14 to 15 and they are set to open individually. Req. fuel is 8,7. Used timing light to verify that 1-st cyl is firing at TDC. I'm not quite sure about my tooth reference table cause I couldnt find any logic in this. Also spark plugs are wet after crancking. I can hear some puffs in the exhaust while crancking, but it won't start. Here's my latest config:

Hello Iwbs,

I have reviewed your trigger, it seems you are still having some hardware issues, your spark events are causing noise on your secondary trigger. That said, does your board have the cam-hall inverter applied or not ?

I suspect you are firing in the wrong phase, so yes, cyl#1 spark lines up with tdc but in exhaust stroke, not compression stroke. Adjust your config accordingly so your cyl#1 spark lines up with cyl#1 in compression phase (offset 360 degrees by adjusting ign out rotation, triggertooth and tdc_delay) and you should be good to go.

Best regards, Dave