Hello, for the past 2 weeks or so I've been chasing a dreaded no spark issue with my recently acquired Audi 80 b4 2L 8V ABK with Digifant 1. The car was running fine and etc when i bough it and brought it home and stuff. But 2 days later when I started it up, it started up just fine but then it died in about a min or so, I've tried restarting it but to no avail, so I took off the battery negative or something I did but next day it started up again fine until it died the same way every since then I couldnt start it up no matter what, this was like 2 weeks ago, ever since I've been trying to figure what is up with this thing.
So I tried service manual with the checks on full ignition system etc. but before that I've replaced : Distributor ( the whole thing) , Ignition coil with module ( the newer style 6N0 xxx p/n) , Spark plug wires, and spark plugs.
The distributor is fine and so is the supply and wires to ecu connector which is a Digifant 1 with 38 pin connector not the newer 45 pin one.
On coil connector I get flashes between pin 2 and pin 3 ( + ) as it should be, but I cannot get it to flash between pin 1 ( ground) and pin 2 ( signal) but according to manual it should but ever since then I figured out that the signal /trigger wire is not a 12V but rather a frequency modulated lower voltage like 2V, 2.5V or so running at 30hz when engine is idle ( 800~ rpm) so my 12v Led tester wont flash there, so I connected multimeter to check voltage but it stays on 0 all the time. Also all the wires have proper continuit and supply specially the signal wire. to ECU
It also doesnt flash if i check between terminal 1 and terminal 15 on the coil and it also should. Also I've been trying to manual fire the coil with 12 supply and it works kind of. But still Im trying to figure out what kind of trigger signal is coming in to trigger it with constant 12v to pin3 and constant ground on pin 1 since I cannot manually discharge it like that.
The only thing that should be left is the ECU, but I also opened the ECU and there is no physical damage that I can see unlike other digifants that like to burn up tracks and stuff. So how couldve it gone bad.
I'd much appreciate some help with this issue its driving me crazy.