No 555 circuit required in the end... as for exact details I'd have to leave that for Matt... It took a few attempts to get the ECU to talk with turning the ignition off and on. But really I was too busy holding my breath and crossing my fingers to pay attention to the entire process. There were many cheers when it started writing.
I did attempt making and hooking up the 555 circuit, I didn't have an oscilloscope to test it, but I was getting roughly the right readings off a multimeter... after I soldered into the ecu board and then resoldered some connections that i'd mangled in moving from my kitchen table to my car... I wasn't getting the right readings anymore, i.e. should see roughly 2.5~3.5V on the timing output and I was getting 0.7V~0.9V
. Also of note, I was bastardising my possibly (probably) dodgy VAG-Com cable not using the FTDI USB-> serial circuit.
So after borrowing a Hyundai Excel, Skoda Scout, Toyota Corolla and a Ford Territory over the last 3 weeks... its sooooooooooooo good being back in the Liberty.
Kudos to Matt once again! Mucho Thanks!
And no more frozen body parts riding the bike to work in canberra winters! (Ok I lie, I probably will still ride the bike, but at least now it won't be because I have to)