My daily driver, Audi S6 avant -95, 2.3L inline 5, 20 valve turbocharged engine (AAN).


Installed VEMS as direct replacement of original ECU (see PlugAndPlayMotronic) using factory wiring. Extra wires are needed only for WBO2. There are some modifications with the trigger wires as well (swap secondary VR signal wires in 3pin JPT connector on firewall).

(Update 13-Jun-2007): Running now with 1.1.24 firmware, configs will follow soon.

old mcd.txt and mct.txt for 1.0.53 (09-Oct-06):

[mcd.txt] [mct.txt]

The engine is now running well, some tuning is still ahead.

Problems with trigger signals with early 55pin motronic box

In InputTrigger/AudiTrigger setup primary trigger has 135 tooth wheel and secondary trigger has single pin on flywheel. Both are detected by VR-sensors. In addition hall sensor in cam is used to synchronize engine phase.

When engine was cranking without injectors or coils connected, trigger log and scoped sensor signal looked perfect. However when either of the previous was connected, car didn't start. It was emitting a few sparks, lost trigger, few sparks etc.

After some measurements it was found out that DC level of secondary trigger signal did drop from 300mV close to 0V when ignition coils were charging or injectors firing. This is probably due the GND wiring. A small ghost signal from primary trigger wheel was enough to trigger false pulses, since LM1815 chip triggers from negative going zero crossings of the signal.

Used secondary trigger setup and measurement results are:

Primary trigger also had 22k pullup to 5V, but it's effect is very minor because of continuous and strong signal from sensor.

Some changes were applied to the trigger, recommended by MembersPage/JorgenKarlsson:

With the applied changes trigger was clean and car started immediately.

Made also some measurements with ignition advance. Ignition was forced to have constant 16deg advance (with mda40 command):

Since TDC pin is set 62 deg before TDC, advace is 62-46 = 16 deg like mde40 suggests

Going to test overlapping dwell with 135-tooth, please review configuration

# reftooth array (mod 135), traversed backwards (0, 54, 108, 162, 216)
h[1]=00 51 1B 6C 36 00 00 00
# for cyl order 5,3,1,2,4 (ignchannels 4,2,0,1,3 in Miska's wiring)
h[2]=04 03 01 00 02 00 00 00
# tooth width in quarterdegrees, 360/135 = 2.667
#  0x0B = 2.75 degrees -> the correct 2.6667 deg will be used. Important to use 0B because 0A is reserved for the volvo 142-tooth.
# with camsync, 270*11 = 2970 mod 256 = 154
another_trigger_tooth=87  # 135 tooth (NOT 0x36=54)
# 60deg
# rpmk=12000/10cyl
ign_tdcdelay=78  # 60 degrees

The h[2] and trigger_tooth, ign_tdcdelay need more thoughts.

27 tooth == trigger_tooth (0x1B) + 0 (h[1] is 0 in the same /"first"/ position where h[2] has ignch4)

Tried to crank with LEDs connected to coil outputs, looks promising; all 5 leds are blinking like expected.

New auditrigger log format - this has nice information and good for upto appr. 5000 RPM (with only 9600 baud)


Some help needed for NTC curvefitting. I'm using pre-generated clt 2063_256.hex table from and it is a pretty close match already. However there is a minor mismatch between the temperatures:

real temp MT display Fahrenheit temp_internal adc temp_internal_wanted
+4C +9C 48 88 = 0x58 157 or 158 79 = 0x4F
+84C +79C 174 214 = 0xD6 decimal 23 223=0xDF
perl </svn/firmware/firmware/branches/stable1_0/inc/ >ntc_propertherm.out 2>ntc_propertherm.err

iterate ended: 2849.40993369509 216.175797314667
SimulatedAnnealing calc_weight() started
23 => 83.1467687787838  (should be 83.8888888888889      so error=-0.742120110105063) 
158 => 4.41775074921436 (should be 3.88888888888889      so error=0.528861860325467) 

adc=23, old=232, new=222, diff=-10
adc=157, old=104, new=81, diff=-23
adc=158, old=103, new=80, diff=-23

(the old is not your old, but old standard curve)

# automatically generated by propertherm, type=clt
# modelparam = 2849.40993369509 Ohm  216.175797314667 aref
# 2252 Ohm in modelparam means that the actually used thermistor exactly matches the reference CURVE, 2297 means that the real 
thing is +2% higher resistance (at given temp) than the reference CURVE

As you see 2849.4 Ohm, AREF=216.175 was found by the simulated annealing iteration (after some tries, for first run the error-square was slightly higher. Commited to SVN so you can play with it yourself (if you measure again).

216/256 * 5= 4.22V : It seems you pullup NTC-s to less than 5V (or aref is higher than 5V). Or there is a measurement error.

Some old things below:

Some open issues to solve

(i had exactly the same thing in my typ 85 with stock motronic AAN connected to the stock coil driven tachometer,specially in higher revs.A resistor solved the problem.But i dont know what is the problem in your setup,hope you find it and share.good luck:MembersPage/NanassyPeter)

Note about the time-saving effect of wiki-written documentation

It's notable that this install was carried out before other competing installs (despite that it was done in the cold, while competing installs had a warm garage host), because documentation discipline was appr 60%.

Competing installs have 10 and 40% documentation discipline so they lost, and might struggle for a few more days or weeks.

Even for this install, 3..5 days could have been saved with 90..100% documentation discipline, the firing order alone could have saved 1..2 days.

Airtemp sensor data:

Some values to make verification easier: Note that pullup is 470 Ohm not 2700 Ohm

Note that the tables are quite steep. The MAT goes from min to max from position 0x75 .. 0x92.

For the prepared tables, look for "PTC" on EasyTherm

Flying wire adaptor for basic functionality from genboard (v3.3) towards motronic connector (pins Mxx)

Hardware changes made to V3.3 board (inside ECM)


Hallo Miska,

now your car is running well? How is the start-up, idle and warm up? How does your car behave in Part and WOT?

Do you managed to get the Knock sensors to Work?

What ignition system are you using? The same as ABY and ADU? Your cylinder head seems like the 3B one.

Can you please post your latest MT file?


Vasilis, MembersPage/Billman

Hi Vasilis,

see MembersPage/Billman/PlugNPlay page for some comments

Hello Miska,

i heard that you made a very successfull Boost Control upgrade.

Can you please make a wikipage for it ,like Gabor Racz did it with hi ALS page?


We would like to really see it in a new upcoming release,and to know what variable is for what.


Question for Miska:

See this page: MembersPage/MattiasSandgren/OskarAudiSFour