It's a 106 gti loom into a Saxo?
I have done several 16v conversions and 106 looms do not work in Saxo's!?
Though the one we had problems with didn't work in many many ways, so it seems odd that the only problem you have is no spark!?
Technically as you have a feed and earth at your coilpack, the other 2 wires go straight back to the control unit to be actuated to create a spark so it wouldn't matter what the loom is out of!?
Have you just plugged the loom in or cut and soldered it?
If its a gti loom you should have a second white plug on it that goes into the inner wing, what did you do with that plug?
Or if it's a Saxo loom it has 2 plugs that go straight into the bottom of the fusebox to feed your ignition relay.
Is it a known good running engine and coilpack?
Do you have a fault code reader?
Where are you located?