NON ZR-1 Technical Help needed

[limey]

You guys are smart and i know we have some ECU geniuses here, so i pose my dilemma.

I'm been trying to convert a lamborghini that uses Marelli 3 pin C.O.P. ignition coils to the more common and easy available VW AUDI 4 Pin coils.

For the love of me, i can't get a spark. I switch back to the 3 pin coil and fires right up.

Ive attached 2 pdf pages, the 2002 Murcielago uses Marelli 3 pin, the 2004 uses VW 4 pin coils.

On the 2002 cars, the coil wiring is as follows:

Pin 1 = 12V Power
Pin 2 = Signal Ground
Pin 3 = ECU Signal

On the 2004 cars, the coil wiring is as follows:

Pin 1 = 12V Power
Pin 2 = Signal Ground
Pin 3 = ECU Signal
Pin 4 = Chassis Ground.

So, why when i ground pin 4 on the 2002 retrofit, the car doesn't fire?