Oskar Nilssons Audi S4

Technical data

Audi S4 2,2t -92, AAN-engine without modifications so far, VEMS v3.3 with Motronic connector, box no. 1045.



The stock IAT is now changed to a standard sensor of NTC-type. The pull-up is changed back to standard 2,7kohm and it seems to works just fine now. EGT is now working as well, it was bad connection between cable and the board which is now fixed. The idle-valve still neeeds some tuning, maybe a diode is the only way to get the valve to function correctly as described on

Q: Since the installation of VEMS I've got a annoying noise in the car-stereo. It appears when the car is running and don't follow the rpm of the car like alternator or ignition noise mostly do. It appeared after the installation of VEMS, haven't changed anything else in the car or cable-harness. Does anyone have a solution for this?


Have fixed the idle problem. It was an old spark plug connector which caused misfiring. Idle air valve still needs some tuning.

The car is now tuned and runs with 1,7bar in boost, have to install an extra fuel pump before I can get more boost. Up next is to replace the stock IAT to a sensor of NTC-type to get faster response and more accuracy.


The FET for that particular injector was dead. The FET driver had survived and was deemed still useful by the experienced engineer who replaced the FET.

The problem was most likely caused by a bad injector connector that had cracked causing an unreliable contact point. Should this kill the FET? Should that depend on what side of the injector had the worst connectivity?

Other than that, the car now runs fine but needs tuning of the idle air valve. After being at high revs and the throttle closed, the engine falls through and stops. Other Audi enthusiasts: please share your IAC settings.


After a couple of months in the garage the car is now updated with a new turbo, injectors and exhaust manifold. I've changed the injectors from the original 349cc/min injectors to Siemens Deka 630cc@3bar. Just changed the req.fuel-value from 13ms to 7.2ms. The engine started with no problem and ran smoothly. After 10km of driving without problem the car started to run on only 4 cylinders.

After some fault-finding I discovered that the injector on cylinder number one was open all the time and filled the cylinder with gasoline quickly. Tried with the old stock injectors but the same thing happened on cylinder number one again. Something has to be wrong in the VEMS-box.

What can have caused this to happen? I'm using the original cable harness and haven't modified anything on the engine besides a new turbo and larger injectors. Since the install of VEMS I've been driving approx. 300km, no problem at all with the old setup with completely stock-engine. Would be grateful if anyone could help me out with this annoying problem.

The engine has been started and given a base VE tune up to 0.6 bar boost, this process took less than 15 minutes after engine was warmed up using the wideband.

The installation was very smooth and it started up right away thanks to great configuration tips and files from MembersPage/MiskaPeippo and MembersPage/TeppoKalske.

More work is needed on the boost controller settings and idle control. Both worked out of the box but two things needs work with the settings:

The boost-problem is solved. It was caused by a huge leak in the rubber hose between the turbo and the intercooler. Tried with open loop to control the boost solenoid manually and with the solenoid completely closed to get maximum boost I still only got 0.6 bar boost. So Miskas configuration for the boost control seems to work. I'll test it when I've fixed the leaking hose.

08.04.03. Have fixed the leaking hose and now the boost is fine when I use open loop for boost-control. With closed loop the boost was very instable. The boost pwm table for closed loop was messed up, just need to fix the table with the values that worked in open loop. The quick response in boost impresses me, full boost comes much quicker now compared to my original 280 hp chip-tuned ECU.

Software configuration

I used 1.1.27, it is the latest stable version to use (as of 2008-03-12). The tables are 12x12, which seems more stable and gives good control over this very easy to tune engine (stock cams).

With some documentation I hope this can be pre-loaded in the pnp Audi boxes delivered.

Latest config 2008-05-06

  • Stock engine tuned to get most power
  • Changed ignition map to get higher advance and more power
  • Cold start needs tuning
  • Runs well for daily driving
  • Open loop boost control works ok, closed loop not so ok

Config 2008-04-22

  • For a stock engine
  • Cold start needs tuning
  • Overall runs well for daily driving, but not tuned for max power
  • Open loop boost control works ok, closed loop not so ok
  • Idle air control valve works adequately

I made up a start configuration from various sources :

  • I have config/tables from Jörgen:
  • An MSQ from an RS2 from one of the Finnish guys:
  • The lambda table uses AFR (In my opinion wrong) and the spark map seems to use (too) high advance on load.
  • Miska Peippo sent an MSQ for AAN using firmware 1.1.27:
  • Very nice config with boost control and idle air valve control
  • One must use a special vemsv3.ini to get control of the special boost control settings that Miska has set up.


In the majority of installations it's very probable that the stock IAT sensor which is of PTC type will be replaced by the web shop IAT that uses standard NTC type. This requires changing the on-board pull-up on the analog input for the IAT back to the standard 2.7K.

This makes the installation less pnp but everyone seems to agree that the stock PTC can be replaced with favourable gains in response and accuracy.

The stock PTC sensor is used for now, but will be changed when the engine is upgraded (intercooler, turbo, exhaust manifold).

Wiki links to Audi information