1994 VW Golf VR6 turbo


16VT’s involvement: Supplied a plug and play Megasquirt ECU to control idle, fuel and ignition, with preloaded base maps for a customer in UAE;


Chassis: stock;

Forced induction: Holset HX40, Audi external wastegate with stock spring, EIP-style split-pulse exhaust manifold, aftermarket 2.5" FMIC, 3” downpipe, 60mm intercooler piping, HKS EBC, HKS blow off valve, 1.0+ bar of boost.

Engine: 2792cc, AAA engine code, 12 valve, free-flow filter & exhaust, C2 spacer to lower CR to 8.5

Injection: Port injection, ~200cc/min stock HighZ injectors, Motronic ECU, 60-2 trigger wheel, variable reluctance crank sensor, PWM 2-wire bosch idle valve, Bosch coolant and GM intake temp sensors, coilpack with integrated module driving 3 coils in wastespark mode

Description: The objective of this install was to use the original wiring loom. To do this, an old 68 pin ECU was cannibalised and turned into an adapter. The MS was installed inside the car, with wires running to the 'ECU' box. All the original sensors and actuators were used. Shielded wires were used for the VR sensor.

MS v3 internal mods included using the CPU outputs directly to drive the VAG ignition module (+5V to trigger coil), with a 330ohm resistor placed inline to limit current drawn from CPU. A TIP122 was installed to PWM control the 4 ohm idle stability valve. Standard GM 2.49k bias resistors were used. C31 was reduced from 0.1uF to 0.001uF to cure VR sensor phase shift.

To make the install compatible with the VAG relays, the following was done:

  1. The ISV was fed +12V by jumpering a wire from T68/23 over to T68/27 through a 10A fuse to provide power to the idle valve.
  2. A relay was used to ground T68/9 when ignition was switched on. Grounding T68/9 allows the ECU relay to come on and feed the injectors, ISV and megasquirt through T68/23.  


Pin configuration:

MS GROUNDS (8,9,10,11) go to T68/1, T68/7, T68/55, T68/56, T68/58

MS SENSOR GROUND (19) goes to T68/33

MS MAT (20) goes to T68/36

MS CLT (21) goes to T68/14

MS TPS SIGNAL (22) goes to T68/40

MS O2 SENSOR SIGNAL (23) goes to T68/20

MS TACH IN aka VR+ (24) goes to T68/67

MS VR- (7) goes to T68/68

MS TPS Vref (26) goes to T68/41

MS coil A (36) goes to T68/8

MS coil B (25) goes to T68/52

MS coil C (27) goes to T68/60

MS +12V (28 ) goes to T68/23 through 5A fuse

MS FIDLE (30) goes to T68/53

MS INJ1 (32,33) goes to T68/2, T68/4 and T68/25

MS INJ2 (34,35) goes to T68/3, T68/24 and T68/26

MS FUEL PUMP (37) goes to T68/6


Options included:

MS LAUNCH CONTROL on DB37 - pin 3, JS11 - SPR1 (yellow wire)

MS Output 1 on DB37 - pin 4, JS2 - SPR2, ZTX450 transistor (green wire)

MS Tacho out DB37 - pin 29 was fed to T68/22 to drive cluster, IAC2A - JS0 

MS SWITCHABLE MAPS on DB37 - pin 31, IAC2B (blue wire)


Crank signal was decoded using MSnS-E HRcode 09a. 60-2 wheel, with 14th (15th if 0 and 1 are the missing teeth) tooth at TDC. Trigger angle 60*. Trigger position A was 5, Trig pos B 25, Trig pos C 45, Trig return pos A 14, Trig return pos B 34, Trig return pos C 54. Spark output was INVERTED since the VW module goes from 0 to 5V when it wants to trigger the coil. Using 3ms on the MS for now.