nasty short circuit

Hello I just finished overhauling my Passat 1781cc model 1993. After some good days of work finally all was set in place. Running the starer, to fill more oil, without the plugs and without the distributor sensor connector, my colleagues near the car said that there is some sparks near the cable harnes, near the motor. it disappeared later. After fitting the plugs the car didn't start... No spark. The brown wire on the coil plug looked melted and odd. The coil's connector was very hard to remove. After it gave up it was seen that the left pin (brown wire) was burnt and the plastic around it melted and caused the gluing of the connector... At some time this week I wrapped all the wiring harness, which was once wrapped with the original black cloth. Probably some wires were already exsposed and by tightening them together some short was happening??? I am going to untie the wrapping and look for the shortcircuit. Does anybody have any lead where to look? Could it have harmed the electronics somewhere? how to check? Thanks Eyal