VW Golf Mk3 Cabrio won't start

[Trubshoe]

This started with the oil in coolant. 2L 8v ADY engine. I have now changed the head gasket, replaced the oil cooler, and the engine speed sensor (still don't know what it does, apart from sensing speed of course)

Now it won't start. The timing has been set, the engine turns over, there appears to be fuel, but no spark, when I hold the HT lead from the coil against the block, I don't get any spark. After fiddling around, with connectors, I did get a healthy spark, then put the lead back into the distributor and tried to start with no luck. Pulled the lead out again and have not seen a spark since. I have replaced the coil once before a few years ago when the car suddenly stopped running. Although this would seem to be too much of a coincidence that it would suddenly fail now!

Does any one know what I should have on the three wires going into the coil, I would imagine one would be -ve one 12v and the other for switching, i.e. 12v on and off with the ignition timing. Any ideas appeciated.

Thanks

Angus

[Trubshoe]

I decided that the engine speed sensor was the only thing I had really changed. I tested the old one by putting a 12V battery between terminals 1 and 3 (1 +ve) and putting a meter between 1 and 2. When I waved a screw drive across the front of the sensor, the meter indicated a pulse of about 9v. I made the same connections to the new sensor in the car, and turned the engine over by had, the meter indicated sod all. I replaced the cable on the old sensor and used RTV and self vulcanising tape to cover the soldered wires. Fitted it to the car and now it starts. I'm very happy, not very happy about the alleged new sensor I bought on ebay.

Regards

Angus