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:
- a special p259-channel activated pulldown on camHall pin EC36/13
- equivalent of disconnecting HALL sensor and grounding the camHALL signal manually
- yes: it's really just that, a convenience feature (1 less step can be useful when expert's VT is connected to v3 over the internet: otherwise it's fairly easy to unplug camHALL-sensor connector)
- when sensor input is pulled down (either with the p259-channel or manually) => camHALL-inverter output is +5V and the crankhome-VR signal goes through
ECU (sectrig=auditrigger w/camhall inverter) originally ordered as assembled is set up that way (unless requested otherwise)
- v3/9467 was sold as
- 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:
- unplug cam-HALL sensor and capture triggerlog (due to internal pullup, which is hopefully installed, the EC36/13 camHALL signal will be high, appr 4V).
- With input=High: Secondary trigger pulses will show up in triggerlog if ECU is set up withOUT camHALL inverter
- assuming still no sectrig pulses seen: connect the camHALL signal to GND with a small wire, or low value resistor 0..270 Ohm and capture another triggerlog (cranking 8..9sec):
- With input=Low: Secondary trigger pulses will show up in triggerlog if ECU is set up with camHALL inverter
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)
- as a simple verification test, insert a 1.0 kOhm resistor between camHALL input and GND.
- Assuming Rpullup=2.7k internal pullup (to 5V) and 1.0 kOhm applied to GND externally during the test: 5/(Rpullup/1.0 + 1) = 1.35 V will be measured approximately.
- else you can calculate internal pullup resistance Rpullup from the measured value using this formula. Substitue the 1.0 with your actually applied pulldown resistance value (in kOhm: eg 0.27 if 270 Ohm pulldown was applied while measuring 0.13V ) : solving for Rpullup=(5/0.13 -1) * 0.27 = 10.1 kOhm
- Assuming Rpullup=2.7k internal pullup (to 5V) and 1.0 kOhm applied to GND externally during the test: 5/(Rpullup/1.0 + 1) = 1.35 V will be measured approximately.
If still no sectrig pulses in any triggerlog (captured with camHALL=hi and low), than crankhome-VR setup must be reviewed carefully.
- Eg. measure crankhome-VR sensor resistance: around 1100..1300 Ohm normally
- measure cranhome-VR signal DC voltage (+50..400mV when sensor is connected; ECU powered up but engine is off).
- internally: sectrig LM1815/pin5 can be left open (for adaptive hysteresis) or connected to +5V (fixed threshold). Possible to get it work either way, but it would be useful information to know which is applied.
- also a scopeshot (say, with an USB scope) could be helpful (perhaps the crankhome-VR signal was inverted twice ?).
- Taking note of wire colors and photo of the VR-connectors would be useful too
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.